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https://hackaday.com/2025/05/16/wireless-doorbell-extension-features-home-wound-coil/ | Wireless Doorbell Extension Features Home-Wound Coil | John Elliot V | [
"home hacks"
] | [
"coil",
"ding-dong doorbell",
"solenoid",
"wireless doorbell"
] | Today in the it’s-surprising-that-it-works department we have a
ding dong doorbell extension
from [Ajoy Raman].
What [Ajoy] wanted to do was to extend the range of his existing doorbell so that he could hear it in his workshop. His plan of attack was to buy a new wireless doorbell and then interface its transmitter with his existing doorbell. But his approach is something others might not have considered if they had have been tasked with this job, and it’s surprising to learn that it works!
What he’s done is wrap a new coil around the ding dong doorbell’s solenoid. When the solenoid activates, a small voltage is induced into the coil. This then gets run into the wireless doorbell transmitter power supply (instead of its battery) via a rectifier diode and a filter capacitor. The wireless doorbell transmitter — having also had its push-button shorted out — operates for long enough from this induced electrical pulse to transmit the signal to the receiver. To be clear: the wireless transmitter is fully powered by the pulse from the coil around the solenoid. Brilliant! Nice hack!
We weren’t sure how reliable the transmitter would be when taken out of the lab and installed in the house so we checked in with [Ajoy] to find out. It’s in production now and operating well at a distance of around 50 feet!
Of course we’ve published heaps of doorbell hacks here on Hackaday before, such as this
Bluetooth Low Energy (BLE) doorbell
and this
light-flashing doorbell
. Have you hacked your own doorbell? Let us know on the
tips line
! | 12 | 6 | [
{
"comment_id": "8128334",
"author": "Bob the builder",
"timestamp": "2025-05-16T08:26:23",
"content": "That’s a neat solution.One of the first projects I built was a copy of this one:https://frenck.dev/diy-smart-doorbell-for-just-2-dollar/Connected it to home assistant and have these google homes a... | 1,760,371,546.155188 | ||
https://hackaday.com/2025/05/15/not-a-sewing-machine-a-multimedia-briefcase/ | Not A Sewing Machine: A Multimedia Briefcase | Al Williams | [
"Teardown"
] | [
"cassette",
"filmstrip",
"Singer"
] | When you think of Singer, you usually think of sewing machines, although if you are a history buff, you might remember they diversified into calculators, flight simulation, and a few other odd businesses for a while. [Techmoan] has an unusual device from Singer that is decidedly not a sewing machine. It is a 1970s-era multimedia briefcase called the
Audio Study Mate
. This odd beast, as you can see in the video below, was a cassette player that also included a 35mm filmstrip viewer. Multimedia 1970s-style!
The film strip viewer is a bright light and a glass screen with some optics. You have to focus the image, and then a button moves the film one frame. However, that’s for manual mode. However, the tape could encode a signal to automatically advance the frame. That didn’t work right away.
Luckily, that required a teardown of the unit to investigate. Inside was a lot of vintage tech, and at some point, the auto advance started working somewhat. It never fully worked, but for a decades-old electromechanical device, it did pretty well.
We do, sometimes, miss what you could pull off with
35mm film
. | 11 | 7 | [
{
"comment_id": "8128339",
"author": "CJay",
"timestamp": "2025-05-16T08:58:21",
"content": "Nice n all but damn, that Swiss Army knife…. Who has pockets that big?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8128358",
"author": "Shannon",
... | 1,760,371,546.048969 | ||
https://hackaday.com/2025/05/15/voyager-1s-primary-thrusters-revived-before-dsn-command-pause/ | Voyager 1’s Primary Thrusters Revived Before DSN Command Pause | Maya Posch | [
"Space"
] | [
"Voyager 1"
] | As with all aging bodies, clogged tubes form an increasing issue. So too with the 47-year old Voyager 1 spacecraft and its hydrazine thrusters. Over the decades silicon dioxide from an aging rubber diaphragm in the fuel tank has been depositing on the inside of fuel tubes. By switching between primary, backup and trajectory thrusters the Voyager team has been managing this issue and kept the spacecraft oriented towards Earth. Now this team has performed another amazing feat
by reviving the primary thrusters
that had been deemed a loss since a heater failure back in 2004.
Unlike the backup thrusters, the trajectory thrusters do not provide roll control, so reviving the primary thrusters would buy the mission a precious Plan B if the backup thrusters were to fail. Back in 2004 engineers had determined that the heater failure was likely unfixable, but over twenty years later the team was willing to give it another shot. Analyzing the original failure data indicated that a glitch in the heater control circuit was likely to blame, so they might actually still work fine.
To test this theory, the team remotely jiggled the heater controls, enabled the primary thrusters and waited for the spacecraft’s star tracker to drift off course so that the thrusters would be engaged by the onboard computer. Making this extra exciting was scheduled maintenance on the Deep Space Network coming up in a matter of weeks, which would have made troubleshooting impossible for months.
To their relief the changes appears to have worked, with the heaters clearly working again, as are the primary thrusters. With this fix in place, it seems that Voyager 1 will be with us for a while longer, even as we
face the inevitable end
to the amazing Voyager program. | 43 | 8 | [
{
"comment_id": "8128261",
"author": "M",
"timestamp": "2025-05-16T02:10:50",
"content": "board computer -> onboard computerswhich would troubleshooting – > which would make troubleshootingchanges appears -> changes appear",
"parent_id": null,
"depth": 1,
"replies": [
{
"co... | 1,760,371,546.480643 | ||
https://hackaday.com/2025/05/15/automatic-transmission-for-manual-transportation/ | Automatic Transmission For Manual Transportation | Bryan Cockfield | [
"Transportation Hacks"
] | [
"automatic transmission",
"bicycle",
"bike",
"gear ratio",
"torque converter"
] | The drivetrain of most modern bicycles has remained relatively unchanged for nearly a century. There have been marginal upgrades here and there like electronic shifting but you’ll still mostly see a chain with a derailleur or two. [Matthew] is taking a swing at a major upgrade to this system by
replacing the front derailleur with a torque converter
, essentially adding an automatic transmission to his bicycle.
Most of us will come across a torque converter in passenger vehicles with automatic transmissions, but these use fluid coupling. [Matthew] has come up with a clever design that uses mechanical coupling instead using a ratchet and pawl mechanism. There are two gear ratios here, a 1:1 ratio like a normal bicycle crank and a 1.5:1 ratio that is automatically engaged if enough torque is applied to the pedals. This means that if a cyclist encounters a hill, the gear automatically shifts down to an easier gear and then will shift back once the strenuous section is finished.
[Matthew] machined all the parts for this build from scratch, and the heavy-duty solid metal parts are both impressive but also show why drivetrains like this haven’t caught on in the larger bicycling world since they’re so heavy. There have been some upgrades in internally geared hubs lately though, which do have a number advantages over traditional chain and derailleur-based bikes with the notable downside of high cost, and there have been some other interesting developments as well like
this folding mechanical drivetrain
and
this all-electric one
.
Thanks to [Keith] for the tip! | 31 | 12 | [
{
"comment_id": "8128226",
"author": "HaHa",
"timestamp": "2025-05-15T23:11:30",
"content": "NO.Slushboxes were a bad idea for cars.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8128246",
"author": "TG",
"timestamp": "2025-05-16T00:59:40",
... | 1,760,371,546.401805 | ||
https://hackaday.com/2025/05/15/laced-peeling-back-pcb-layers-with-chemical-etching-and-a-laser/ | LACED: Peeling Back PCB Layers With Chemical Etching And A Laser | Maya Posch | [
"Reverse Engineering"
] | [
"etching PCBs",
"laser engraving"
] | Once a printed circuit board (PCB) has been assembled it’s rather hard to look inside of it, which can be problematic when you have e.g. a multilayer PCB of an (old) system that you really would like to dissect to take a look at the copper layers and other details that may be hidden inside, such as Easter eggs on inner layers. [Lorentio Brodeso]’s
‘LACED’ project
offers one such method, using both chemical etching and a 5 Watt diode engraving laser to remove the soldermask, copper and FR4 fiberglass layers.
This project uses sodium hydroxide (NaOH) to dissolve the solder mask, followed by hydrogen chloride (HCl) and hydrogen peroxide (H
2
O
2
) to dissolve the copper in each layer. The engraving laser is used for the removing of the FR4 material. Despite the ‘LACED’ acronym standing for
Laser-Controlled Etching and Delayering
, the chemical method(s) and laser steps are performed independently from each other.
This makes it in a way a variation on the more traditional CNC-based method, as
demonstrated by [mikeselectricstuff]
(as shown in the top image) back in 2016, alongside the
detailed setup video
of how a multi-layer PCB was peeled back with enough resolution to make out each successive copper and fiberglass layer.
The term ‘laser-assisted etching’ is generally used for e.g.
glass etching with HF or KOH
in combination with a femtosecond laser to realize high-resolution optical features,
‘selective laser etching’
where the etchant is assisted by the laser-affected material, or the related
laser-induced etching
of hard & brittle materials. Beyond these there is a
whole world
of laser-induced or laser-activated etching or functionalized methods, all of which require that the chemical- and laser-based steps are used in unison.
Aside from this, the use of chemicals to etch away soldermask and copper does of course leave one with a similar messy clean-up as when etching new PCBs, but it can provide more control due to the selective etching, as a CNC’s carbide bit will just as happily chew through FR4 as copper. When reverse-engineering a PCB you will have to pick whatever method works best for you.
Top image: Exposed inner copper on multilayer PCB. (Credit:
mikeselectricstuff
, YouTube) | 9 | 2 | [
{
"comment_id": "8128183",
"author": "Lorentio Brodesco",
"timestamp": "2025-05-15T21:08:39",
"content": "I’m Lorentio Brodesco, the creator of LACED, and I feel compelled to leave a response because, frankly, this article significantly underrepresents the essence and technical depth of the project.... | 1,760,371,546.104277 | ||
https://hackaday.com/2025/05/15/mylar-space-blankets-as-rf-reflectors/ | Mylar Space Blankets As RF Reflectors | Jenny List | [
"Radio Hacks"
] | [
"antenna",
"HF",
"mylar",
"reflector"
] | Metalized Mylar “space blankets” are sold as a survivalist’s accessory, primarily due to their propensity for reflecting heat. They’re pretty cheap, and [HamJazz] has performed some experiments on their RF properties. Do they reflect radio waves as well as they reflect heat? As it turns out,
yes they do
.
Any antenna system that’s more than a simple radiator relies on using conductive components as reflectors. These can either be antenna elements, or the surrounding ground acting as an approximation to a conductor. Radio amateurs will often use wires laid on the ground or buried within it to improve its RF conductivity, and it’s in this function that he’s using the Mylar sheet. Connection to the metalized layer is made with a magnet and some aluminium tape, and the sheet is strung up from a line at an angle. It’s a solution for higher frequencies only due to the restricted size of the thing, but it’s certainly interesting enough to merit further experimentation.
As you can see in the video below, his results are derived in a rough and ready manner with a field strength meter. But they certainly show a much stronger field on one side resulting from the Mylar, and also in an antenna that tunes well. We would be interested to conduct a received signal strength test over a much greater distance rather than a high-level field strength test so close to the antenna, but it’s interesting to have a use for a space blanket that’s more than just keeping the sun away from your tent at a hacker camp.
Perhaps it could even form a parabolic antenna
.
Thanks [Fl.xy] for the tip! | 11 | 9 | [
{
"comment_id": "8128143",
"author": "TG",
"timestamp": "2025-05-15T18:55:15",
"content": "They make mylar umbrellas as well. Wonder how one of those would perform.. Or if you could tweak it with different springy ribs or positions for the latch so that it better approximates a parabola",
"paren... | 1,760,371,546.200253 | ||
https://hackaday.com/2025/05/15/remembering-more-memory-xms-and-a-real-hack/ | Remembering More Memory: XMS And A Real Hack | Al Williams | [
"Hackaday Columns",
"Retrocomputing"
] | [
"8086",
"8088",
"ems",
"pc",
"protected mode",
"unreal mode",
"XMS"
] | Last time we talked about how the original PC has a limit of 640 kB for your programs and 1 MB in total
. But of course those restrictions chafed. People demanded more memory, and there were workarounds to provide it.
However, the workarounds were made to primarily work with the old 8088 CPU. Expanded memory (EMS) swapped pages of memory into page frames that lived above the 640 kB line (but below 1 MB). The system would work with newer CPUs, but those newer CPUs could already address more memory. That led to new standards, workarounds, and even a classic hack.
XMS
If you had an 80286 or above, you might be better off using extended memory (XMS). This took advantage of the fact that the CPU could address more memory. You didn’t need a special board to load 4MB of RAM into an 80286-based PC. You just couldn’t get to with MSDOS. In particular, the memory above 1 MB was — in theory — inaccessible to real-mode programs like MSDOS.
Well, that’s not strictly true in two cases. One, you’ll see in a minute. The other case is because of the overlapping memory segments on an 8088, or in real mode on later processors. Address FFFF:000F was the top of the 1 MB range.
PCs with more than 20 bits of address space ran into problems since some programs “knew” that memory access above that would wrap around. That is FFFF:0010, on an 8088, is the same as 0000:0000. They would block A20, the 21st address bit, by default. However, you could turn that block off in software, although exactly how that worked varied by the type of motherboard — yet another complication.
XMS allowed MSDOS programs to allocate and free blocks of memory that were above the 1 MB line and map them into that special area above FFFF:0010, the so-called high memory area (HMA).
The 640 kB user area, 384 kB system area, and almost 64 kB of HMA in a PC (80286 or above)
Because of its transient nature, XMS wasn’t very useful for code, but it was a way to store data. If you weren’t using it, you could load some TSRs into the HMA to prevent taking memory from MSDOS.
Protected Mode Hacks
There is another way to access memory above the 1 MB line: protected mode. In protected mode, you still have a segment and an offset, but the segment is just an index into a table that tells you where the segment is and how big it is. The offset is just an offset into the segment. So by setting up the segment table, you can access any memory you like. You can even set up a segment that starts at zero and is as big as all the memory you can have.
A protected mode segment table entry
You can use segments like that in a lot of different ways, but many modern operating systems do set them up very simply. All segments start at address 0 and then go up to the top of user memory. Modern processors, 80386s and up, have a page table mechanism that lets you do many things that segments were meant to do in a more efficient way.
However, MS-DOS can’t deal with any of that directly. There were many schemes that would switch to protected mode to deal with upper memory using EMS or XMS and then switch back to real mode.
Unfortunately, switching back to real mode was expensive because, typically, you had to set a bit in non-volatile memory and reboot the computer! On boot, the BIOS would notice that you weren’t really rebooting and put you back where you were in real mode. Quite a kludge!
There was a better way to run MSDOS in protected mode called Virtual86 mode. However, that was complex to manage and required many instructions to run in an emulated mode, which wasn’t great for performance. It did, however, avoid the real mode switch penalty as you tried to access other memory.
Unreal Mode
In true hacker fashion,
several of us figured out something
that later became known as Unreal Mode. In the CPU documentation, they caution you that before switching to real mode, you need to set all the segment tables to reflect what a segment in real mode looks like. Obviously, you have to think, “What if I don’t?”
Well, if you don’t, then your segments can be as big as you like. Turns out, apparently, some people knew about this even though it was undocumented and perhaps under a non-disclosure agreement. [Michal Necasek] has
a great history about the people who independently discovered it
, or at least, the ones who talked about it publicly.
The method was doomed, though, because of Windows. Windows ran in protected mode and did its own messing with the segment registers. If you wanted to play with that, you needed a different scheme, but that’s another story.
Modern Times
These days, we don’t even use video cards with a paltry 1 MB or even 100 MB of memory! Your PC can adroitly handle tremendous amounts of memory. I’m writing this on a machine with 64 GB of physical memory. Even my smallest laptop has 8 GB and at least one of the bigger ones has more.
Then there’s virtual memory, and if you have solid state disk drives, that’s probably faster than the old PC’s memory, even though today it is considered slow.
Modern memory systems almost don’t resemble these old systems even though we abstract them to pretend they do. Your processor really runs out of cache memory. The memory system probably manages several levels of cache. It fills the cache from the actual RAM and fills that from the paging device. Each program can have a totally different view of physical memory with its own idea of what physical memory is at any given address. It is a lot to keep track of.
Times change. EMS, XMS, and Unreal mode seemed perfectly normal in their day. It makes you wonder what things we take for granted today will be considered backward and antiquated in the coming decades. | 28 | 7 | [
{
"comment_id": "8128116",
"author": "George",
"timestamp": "2025-05-15T17:12:46",
"content": "We used 8088 and 8086 a lot for embedded systems we designed. IAR compiler had a banked memory model. Easy to turn on. Then each memory area (RAM and ROM) has a section that was always present and anoth... | 1,760,371,545.952745 | ||
https://hackaday.com/2025/05/15/fpv-drone-takes-off-from-a-rocketing-start/ | FPV Drone Takes Off From A Rocketing Start | Ian Bos | [
"drone hacks"
] | [
"3d printing",
"amateur rocketry",
"DIYdrones",
"drone fpv"
] | Launching rockets into the sky can be a thrill, but why not make the fall just as interesting? That is exactly what
[I Build Stuff]
thought when attempting to build a self-landing payload. The idea is to release a can sized “satellite” from a rocket at an altitude upwards of 1 km, which will then fly back down to the launch point.
The device itself is a first-person view (FPV) drone running the popular Betaflight firmware. With arms that swing out with some of the smallest brushless motors you’ve ever seen (albeit not
the
smallest motor
), the satellite is surprisingly capable. Unfortunately due to concerns over the legality of an autonomous payload, the drone is human controlled on the descent.
Using collaborated efforts, a successful launch was flown with the satellite making it to the ground unharmed, at least for the most part. While the device did show capabilities of being able to fly back, human error led to a manual recovery. Of course, this is far from the only rocketry hack we have seen here at Hackaday. If you are more into making the flight itself interesting, here is a record breaking one from
USC students
.
Thank you [Hari Wiguna] for the great tip! | 24 | 6 | [
{
"comment_id": "8128102",
"author": "JJ Alpha",
"timestamp": "2025-05-15T16:24:59",
"content": "Awesome, MIRV FPVs, if the war keeps up it will be 20% more horrific in a few months",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8128441",
"author": "... | 1,760,371,546.330375 | ||
https://hackaday.com/2025/05/15/falling-down-the-land-camera-rabbit-hole/ | Falling Down The Land Camera Rabbit Hole | Jenny List | [
"chemistry hacks",
"Featured",
"History",
"Interest",
"Slider"
] | [
"edwin land",
"photography",
"polaroid"
] | It was such an innocent purchase, a slightly grubby and scuffed grey plastic box with the word “
P O L A R O I D
” intriguingly printed along its top edge. For a little more than a tenner it was mine, and I’d just bought one of Edwin Land’s instant cameras. The film packs it takes are now a decade out of production, but my Polaroid 104 with its angular 1960s styling and vintage bellows mechanism has all the retro-camera-hacking appeal I need. Straight away I 3D printed an adapter and new back allowing me to use 120 roll film in it, convinced I’d discover in myself a medium format photographic genius.
But who wouldn’t become fascinated with the film it should have had when faced with such a camera? I have form on this front after all, because a similar chance purchase of a defunct-format movie camera a few years ago
led me into re-creating its no-longer-manufactured cartridges
. I had to know more, both about the instant photos it would have taken, and those film packs. How did they work?
A Print, Straight From The Camera
An instant photograph reveals itself. Akos Burg, courtesy of
One Instant
.
In conventional black-and-white photography the film is exposed to the image, and its chemistry is changed by the light where it hits the emulsion. This latent image is rolled up with all the others in the film, and later revealed in the developing process. The chemicals cause silver particles to precipitate, and the resulting image is called a negative because the silver particles make it darkest where the most light hit it. Positive prints are made by exposing a fresh piece of film or photo paper through this negative, and in turn developing it. My Polaroid camera performed this process all-in-one, and I was surprised to find that behind what must have been an immense R&D effort to perfect the recipe, just how simple the underlying process was.
My dad had a Polaroid pack film camera back in the 1970s, a big plastic affair that he used to take pictures of the things he was working on. Pack film cameras weren’t like the motorised Polaroid cameras of today with their all-in-one prints, instead they had a paper tab that you pulled to release the print, and a peel-apart system where after a time to develop, you separated the negative from the print. I remember as a youngster watching this process with fascination as the image slowly appeared on the paper, and being warned not to touch the still-wet print or negative when it was revealed. What I was looking at wasn’t a negative printing process as described in the previous paragraph but something else, one in which the unexposed silver halide compounds which make the final image are diffused onto the paper from the less-exposed areas of the negative, forming a positive image of their own when a reducing agent precipitates out their silver crystals. Understanding the subtleties of this process required a journey back to the US Patent Office in the middle of the 20th century.
It’s All In The Diffusion
The illustration from Edwin Land’s patent US2647056.
It’s in
US2647056
that we find a comprehensive description of the process, and the first surprise is that the emulsion on the negative is the same as on a contemporary panchromatic black-and-white film. The developer and fixer for this emulsion are also conventional, and are contained in a gel placed in a pouch at the head of the photograph. When the exposed film is pulled out of the camera it passes through a set of rollers that rupture this pouch, and then spread the gel in a thin layer between the negative and the coated paper. This gel has two functions: it develops the negative, but over a longer period it provides a wet medium for those unexposed silver halides to diffuse through into the now-also-wet coating of the paper which will become the print. This coating contains a reducing agent, in this case a metalic sulphide, which over a further period precipitates out the silver that forms the final visible image. This is what gives Polaroid photographs their trademark slow reveal as the chemistry does its job.
I’ve just described the black and white process; the colour version uses the same diffusion mechanism but with colour emulsions and dye couplers in place of the black-and-white chemistry. Meanwhile modern one-piece instant processes from Polaroid and Fuji have addressed the problem of making the image visible from the other side of the paper, removing the need for a peel-apart negative step.
Given that the mechanism and chemistry are seemingly so simple, one might ask why we can no longer buy two-piece Polaroid pack or roll film except for
limited quantities of hand-made packs
from One Instant. The answer lies in the complexity of the composition, for while it’s easy to understand how it works, it remains difficult to replicate the results Polaroid managed through a huge amount of research and development over many decades. Even
the Impossible Project
, current holders of the Polaroid brand, faced a significant effort to completely replicate the original Polaroid versions of their products when they brought the last remaining Polaroid factory to production back in 2010 using the original Polaroid machinery. So despite it retaining a fascination among photographers, it’s unlikely that we’ll see peel-apart film for Polaroid cameras return to volume production given the small size of the potential market.
Hacking A Sixty Year Old Camera
Five minutes with a Vernier caliper and openSCAD, and this is probably the closest I’ll get to a pack film of my own.
So having understood how peel-apart pack film works and discovered what is available here in 2025, what remains for the camera hacker with a Land camera? Perhaps the simplest idea would be to buy one of those One Instant packs, and use it as intended. But we’re hackers, so of course you will want to
print that 120 conversion kit I mentioned
, or find an old pack film cartridge and stick a sheet of photographic paper or even a Fuji Instax sheet in it. You’ll have to retreat to the darkroom and develop the film or run the Instax sheet through an Instax camera to see your images, but it’s a way to enjoy some retro photographic fun.
Further than that, would it be possible to load Polaroid 600 or i-Type sheets into a pack film cartridge and somehow give them paper tabs to pull through those rollers and develop them? Possibly, but all your images would be back to front. Sadly, rear-exposing Instax Wide sheets wouldn’t work either because their developer pod lies along their long side. If you were to manage loading a modern instant film sheet into a cartridge, you’d then have to master the intricate paper folding arrangement required to ensure the paper tabs for each photograph followed each other in turn. I have to admit that I’ve become fascinated by this in considering my Polaroid camera. Finally, could you make your own film? I would of course say no, but incredibly
there are people who have achieved results doing just that
.
My Polaroid 104 remains an interesting photographic toy, one I’ll probably try a One Instant pack in, and otherwise continue with the 3D printed back and shoot the occasional 120 roll film. If you have one too, you might find
my 3D printed AAA battery adapter
useful. Meanwhile it’s the cheap model without the nice rangefinder so it’ll never be worth much, so I might as well just enjoy it for what it is. And now I know a little bit more about his invention, admire Edwin Land for making it happen.
Any of you out there hacking on Polaroids? | 24 | 11 | [
{
"comment_id": "8128132",
"author": "Mike",
"timestamp": "2025-05-15T18:26:59",
"content": "I recently bought a typewriter. Then I bought another one…",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8128163",
"author": "HaHa",
"timestamp": "2025-05-15T... | 1,760,371,546.267376 | ||
https://hackaday.com/2025/05/15/welcome-your-new-ai-lego-overlord/ | Welcome Your New AI (LEGO) Overlord | Al Williams | [
"Artificial Intelligence",
"Toy Hacks"
] | [
"ai",
"lego",
"LLM"
] | You’d think a paper from a science team from Carnegie Mellon would be short on fun. But the team behind
LegoGPT
would prove you wrong. The system allows you to enter prompt text and produce physically stable LEGO models. They’ve done more than just a paper. You can find a
GitHub
repo and a running
demo
, too.
The authors note that the automated generation of 3D shapes has been done. However, incorporating real physics constraints and planning the resulting shape in LEGO-sized chunks is the real topic of interest. The actual project is a set of training data that can transform text to shapes. The real work is done using one of the LLaMA models. The training involved converting Lego designs into tokens, just like a chatbot converts words into tokens.
There are a lot of parts involved in the creation of the designs. They convert meshes to LEGO in one step using 1×1, 1×2, 1×4, 1×6, 1×8, 2×2, 2×4, and 2×6 bricks. Then they evaluate the stability of the design. Finally, they render an image and ask GPT-4o to produce captions to go with the image.
The most interesting example is when they feed robot arms the designs and let them make the resulting design. From text to LEGO with no human intervention! Sounds like something from a bad movie.
We wonder if they added the more advanced LEGO sets, if we could ask for our own
Turing machine
? | 13 | 5 | [
{
"comment_id": "8128023",
"author": "Lightislight",
"timestamp": "2025-05-15T11:28:37",
"content": "Millions of dollars, high tech equipment, some of the worlds greatest minds, a top university, and yes we have finally done it. Children’s toys can now be constructed by robots.",
"parent_id": nu... | 1,760,371,546.004357 | ||
https://hackaday.com/2025/05/15/smart-terrarium-run-by-esp32/ | Smart Terrarium Run By ESP32 | Lewin Day | [
"home hacks",
"Microcontrollers"
] | [
"ESP32",
"plant life",
"plants",
"terrarium"
] | A terrarium is a little piece of the living world captured in a small enclosure you can pop on your desk or coffee table at home. If you want to keep it as alive as possible, though, you might like to implement some controls. That’s precisely what
[yotitote] did with their smart terrarium build
.
At the heart of the build is an ESP32 microcontroller. It’s armed with temperature and humidity sensors to detect the state of the atmosphere within the terrarium itself. However, it’s not just a mere monitor. It’s able to influence conditions by activating an ultrasonic fogger to increase humidity (which slightly impacts temperature in turn). There are also LED strips, which the ESP32 controls in order to try and aid the growth of plants within, and a small OLED screen to keep an eye on the vital signs.
It’s a simple project, but one that serves as a basic starting point that could be readily expanded as needed. It wouldn’t take much to adapt this further, such as by adding heating elements for precise temperature control, or more advanced lighting systems. These could be particularly useful if you intend your terrarium to support, perhaps, reptiles, in addition to tropical plant life.
Indeed, we’ve seen similar work before, using a Raspberry Pi
to create a positive environment to keep geckos alive!
Meanwhile, if you’re cooking up your own advanced terrarium at home, don’t hesitate to
let us know. | 8 | 4 | [
{
"comment_id": "8127998",
"author": "PatG",
"timestamp": "2025-05-15T09:24:05",
"content": "I’m doing something similar for my mushroom grow-tent :)",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8128003",
"author": "Carl Breen",
"timestamp"... | 1,760,371,546.705391 | ||
https://hackaday.com/2025/05/14/fancy-adding-a-transputer-or-two-to-your-atari-st/ | Fancy Adding A Transputer Or Two To Your Atari ST? | Dave Rowntree | [
"Retrocomputing"
] | [
"atari st",
"ATW800",
"fpga",
"inmos",
"Mega-ST",
"Tang 20k",
"transputer",
"VME"
] | Has anybody heard of the ATW800 transputer workstation? The one that used a modified Atari ST motherboard as a glorified I/O controller for a T-series transputer? No, we hadn’t either, but transputer superfan [Axel Muhr] has created the
ATW800/2, an Atari Transputer card, the way it was meant to be.
The transputer was a neat idea when it was conceived in the 1980s. It was designed specifically for parallel and scientific computing and featured an innovative architecture and dedicated high-speed serial chip-to-chip networking. However, the development of more modern buses and general-purpose CPUs quickly made it a footnote in history. During the same period, a neat transputer-based parallel processing computer was created, which leveraged the Atari ST purely for its I/O. This was the curious
ATW800 transputer workstation
. That flopped as well, but [Axel] was enough of a fan to take that concept and run with it. This time, rather than using the Atari as a dumb I/O controller, the card is explicitly designed for the Mega-ST expansion bus. A second variant of the ATW800/2 is designed for the Atari VME bus used by the STe and TT models—yes, VME on an Atari—it was a thing.
The card hosts an FPGA module, specifically the
Tang 20k
, that handles the graphics, giving the Atari access to higher resolutions, HDMI output, and GPU-like acceleration with the right code. The FPGA also contains a ‘synthetic’ transputer core, compatible with the
Inmos T425
, with 6Mb of RAM to play with. Additionally, the board contains an original Inmos C011 link adapter chip and a pair of size-1
TRAM slots
to install two physical transputer cards. This allows a total of two transputers, each with its dedicated RAM, to be installed and networked with the synthetic transputer and the host system. The FPGA is configured to allow the host CPU and any of the transputers direct access to the video RAM, so with proper coding, the same display can mix 68K and parallel computing applications simultaneously. The original ATW800 couldn’t do that!
In addition to the transputer support and boosted graphics, the card also provides a ROM big enough to switch between multiple Atari TOS versions, USB loop-through ports to hook up to a
lightning-ST
board, and a MicroSD slot for extra local storage. What a project!
If you don’t know what the transputer is (or was),
read our quick guide
. Of course, forty-year-old silicon is rare and expensive nowadays, so if you fancy playing with some hardware, might we suggest
using a Pi Pico instead
?
Thanks to [krupkaj] for the tip! | 9 | 5 | [
{
"comment_id": "8127960",
"author": "Tom G",
"timestamp": "2025-05-15T06:34:55",
"content": "The modern version of the Transputer and Occam are alive and kicking: buy them at DigiKey.They are the XMOS xCORE processors (4000MIPS/chip, expandable) and xC.Unique benefit: they givehardrealtime process... | 1,760,371,546.574687 | ||
https://hackaday.com/2025/05/14/inside-starlinks-user-terminal/ | Inside Starlink’s User Terminal | Al Williams | [
"Teardown"
] | [
"reverse engineering",
"satellite",
"Starlink"
] | If you talk about Starlink, you are usually talking about the satellites that orbit the Earth carrying data to and from ground stations. Why not? Space is cool. But there’s another important part of the system: the terminals themselves. Thanks to [DarkNavy], you don’t have to tear one open yourself to
see what’s inside
.
The terminal consists of two parts: the router and the antenna. In this context, antenna is somewhat of a misnomer, since it is really the RF transceiver and antenna all together. The post looks only at the “antenna” part of the terminal.
The unit is 100% full of printed circuit board with many RF chips and a custom ST Microelectronics Cortex A-53 quad-core CPU. There was a hack to gain root shell on the device. This led to SpaceX disabling the UART via a firmware update. However, there is
still a way to break in
.
[DarkNavy] wanted to look at the code, too, but there was no easy way to dump the flash memory. Desoldering the eMMC chip and reading it was, however, productive. The next step was to create a virtual environment to run the software under Qemu.
There were a few security questions raised. We wouldn’t call them red flags,
per see
, but maybe pink flags. For example, there are 41 trusted ssh keys placed in the device’s authorized_keys file. That seems like a lot for a production device on your network, but it isn’t any smoking gun.
We’ve watched the cat-and-mouse between Starlink and people hacking the receivers with interest. | 34 | 9 | [
{
"comment_id": "8127925",
"author": "Truth",
"timestamp": "2025-05-15T03:21:16",
"content": "41 trusted ssh keysAt a guess, they are the exact same public ssh keys on all StarLink terminals globally. I can not see anything that could possibly go wrong with that :)",
"parent_id": null,
"dept... | 1,760,371,546.657777 | ||
https://hackaday.com/2025/05/14/led-layer-makes-plywood-glow/ | LED Layer Makes Plywood Glow | Tyler August | [
"Art",
"Microcontrollers"
] | [
"bending acrylic",
"bending plywood",
"CO2 laser cutter",
"custom plywood",
"epoxy",
"PY32",
"RGB LED"
] | Plywood is an interesting material: made up of many layers of thin wood plys, it can be built up into elegantly curved shapes. Do you need to limit it to just wood, though? [Zach of All Trades] has proved you do not, when he embedded a light guide, LEDs, microcontrollers and touch sensors
into a quarter inch (about six millimeter) plywood layup
in the video embedded below.
He’s using custom flexible PCBs, each hosting upto 3 LEDs and the low-cost PY32 microcontroller. The PY32 drives the RGB LEDs and handles capacitive touch sensing within the layup. In the video, he goes through his failed prototypes and what he learned: use epoxy, not wood glue, and while clear PET might be nice and bendy, acrylic is going to hold together better and cuts easier with a CO2 laser.
The wood was sourced from a couple of sources, but the easiest was apparently skateboard kits– skateboards are plywood, and there’s a market of people who DIY their decks. The vacuum bag setup [Zach] used looks like an essential tool to hold together the layers of wood and plastic as the epoxy cures. To make the bends work [Zach] needed a combination of soaking and steaming the maple, before putting it into a two-part 3D printed mold. The same mold bends the acrylic, which is pre-heated in an oven.
Ultimately it didn’t
quite
come together, but after some epoxy pour touch-up he’s left with a fun and decorative headphone stand. [Zach] has other projects in mind with this technique, and its got our brains percolating as well. Imagine incorporating strain gauges to drive the LEDs so you could see loading in real time, or a sound-reactive speaker housing. The sky’s the limit now that the technique is out there, and we look forward to see what people make of it.
The last time we heard from [Zach of All Trades] he was
comparing ten cent micro-controllers
; it looks like the PY32 came out on top. Oddly enough, this seems to be the first hack we have featuring it. If you’ve done something neat with ten cent micros (or more expensive ones) or know someone who did, don’t forget to
let us know! We love tips
. [Zach] sent in the tip about this video, and his reward is gratitude worth its weight in gold. | 4 | 4 | [
{
"comment_id": "8128009",
"author": "macsimki",
"timestamp": "2025-05-15T10:39:34",
"content": "very elegant. without the headphone its an art piece by itself.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8128025",
"author": "TDT",
"timestamp": "202... | 1,760,371,546.929012 | ||
https://hackaday.com/2025/05/13/trackside-observations-of-a-rail-power-enthusiast/ | Trackside Observations Of A Rail Power Enthusiast | Jenny List | [
"Featured",
"Interest",
"Original Art",
"Slider",
"Transportation Hacks"
] | [] | The life of a Hackaday writer often involves hours spent at a computer searching for all the cool hacks you love, but its perks come in not being tied to an office, and in periodically traveling around our community’s spaces. This suits me perfectly, because as well as having an all-consuming interest in technology, I am a lifelong rail enthusiast. I am rarely without an Interrail pass, and for me Europe’s railways serve as both comfortable mobile office space and a relatively stress free way to cover distance compared to the hell of security theatre at the airport. Along the way I find myself looking at the infrastructure which passes my window, and I have become increasingly fascinated with the power systems behind electric railways. There are so many different voltage and distribution standards as you cross the continent, so just how are they all accommodated? This deserves a closer look.
So Many Different Ways To Power A Train
Diesel trains like this one are for the dinosaurs.
In Europe where this is being written, the majority of main line railways run on electric power, as do many subsidiary routes. It’s not universal, for example my stomping ground in north Oxfordshire is still served by diesel trains, but in most cases if you take a long train journey it will be powered by electricity. This is a trend reflected in many other countries with large railway networks, except sadly for the United States, which has electrified only a small proportion of its huge network.
Of those many distribution standards there are two main groups when it comes to trackside, those with an overhead wire from which the train takes its power by a pantograph on its roof, or those with a third rail on which the train uses a sliding contact shoe. It’s more usual to see third rails in use on suburban and metro services, but if you take a trip to Southern England you’ll find third rail electric long distance express services. There are even four-rail systems such as the London Underground, where the fourth rail serves as an insulated return conductor to prevent electrolytic corrosion in the cast-iron tunnel linings.
These tracks in the south of England each have a 750 VDC third rail. Lamberhurst, CC BY-SA 4.0.
As if that wasn’t enough, we come to the different voltage standards. Those southern English trains run on 750 V DC while their overhead wire equivalents use 25 kV AC at 50Hz, but while Northern France also has 25 kV AC, the south of the country shares the same 3 kV DC standard as Belgium, and the Netherlands uses 1.5 kV DC. More unexpected still is Germany and most of Scandinavia, which uses 15 kV AC at only 16.7 Hz. This can have an effect on the trains themselves, for example Dutch trains are much slower than those of their neighbours because their lower voltage gives them less available energy for the same current.
This Dutch locomotive is on its 1.5 kV home turf, but it’s hauling an international service headed for the change to 3 kV DC in Belgium.
In general these different standards came about partly on national lines, but also their adoption depends upon how late the country in question electrified their network. For example aside from that southern third-rail network and a few individual lines elsewhere, the UK trains remained largely steam-powered until the early 1960s. Thus its electrification scheme used the most advanced option, 25 kV 50 Hz overhead wire. By contrast countries such as Belgium and the Netherlands had committed to their DC electrification schemes early in the 20th century and had too large an installed base to change course. That’s not to say that it’s impossible to upgrade though, as for example in India where 25 kV AC electrification has proceeded since the late 1950s and has included the upgrade of an earlier 1.5 kV DC system.
A particularly fascinating consequence of this comes at the moment when trains cross between different networks. Sometimes this is done in a station when the train isn’t moving, for example at Ashford in the UK when high-speed services switch between 25 kV AC overhead wire and 750 V DC third rail, and in other cases it happens on the move through having the differing voltages separated by a neutral section of overhead cable. Sadly I have never manged to travel to the Belgian border and witness this happening. Modern electric locomotives are often equipped to run from multiple voltages and take such changes in their stride.
Power To The People Movers
The 4-rail 750VDC system on the London Underground.
Finally, all this rail electrification infrastructure needs to get its power from somewhere. In the early days of railway electrification this would inevitably been a dedicated railway owned power station, but now it is more likely to involve a grid connection and some form of rectifier in the case of DC lines. The exception to this are systems with differing AC frequencies from their grid such as the German network, which has an entirely separate power generation and high voltage distribution system.
So that was the accumulated observations of a wandering Hackaday scribe, from the comfort of her air-conditioned express train. If I had to name my favourite of all the networks I have mentioned it would be the London Underground, perhaps because the warm and familiar embrace of an Edwardian deep tube line on a cold evening is an evocative feeling for me. When you next get the chance to ride a train keep an eye out for the power infrastructure, and may the experience be as satisfying and comfortable as it so often is for me.
Header image: SPSmiler,
Public domain
. | 59 | 14 | [
{
"comment_id": "8127177",
"author": "Tyler August",
"timestamp": "2025-05-13T14:19:08",
"content": "“This is a trend reflected in many other countries with large railway networks, except sadly for the United States, which has electrified only a small proportion of its huge network.” — and Canada, w... | 1,760,371,547.172718 | ||
https://hackaday.com/2025/05/13/studying-qr-code-degradation/ | Studying QR Code Degradation | Jenny List | [
"Repair Hacks"
] | [
"cliff edge",
"error correction",
"qr code"
] | It’s fair to say that QR codes are a technology that has finally come of age. A decade or more ago they were a little over-hyped and sometimes used in inappropriate or pointless ways, but now they are an accepted and useful part of life.
They’re not without their faults though, one of which is that despite four increasingly redundant levels of error correction, there comes a point at which a degraded QR code can no longer be read.
[HumanQR] is soliciting these broken QR codes for research purposes
and inclusion in an eventual open-source database, and they’ll even have a shot at repairing your submissions for you.
It’s a problem inherent to all digital media, that once the limit of whatever error correction they contain has been reached, they arrive at
a cliff-edge at which they go immediately from readability to non readability
. The example given in the linked article is a locator tag on a stray cat, it had been rubbed away in part. Improving its contrast, sharply defining its edges, and improving the definition of its fiducials was able to revive it, we hope leading to the cat being returned home.
The idea is that by studying enough damaged codes it should be possible to identify the means by which they become degraded, and perhaps come up with a way to inform some repair software. Meanwhile if you are interested, you might want to learn more about how they work,
the hard way
. | 30 | 8 | [
{
"comment_id": "8127106",
"author": "Iván Stepaniuk",
"timestamp": "2025-05-13T11:06:44",
"content": "Sadly, many QR codes are broken before they even get printed. Someone had the brilliant idea to start abusing the data redundancy mechanism to put whatever logo in the middle of it, make them color... | 1,760,371,547.286463 | ||
https://hackaday.com/2025/05/13/simulating-high-side-bootstrap-circuits-with-ltspice/ | Simulating High-Side Bootstrap Circuits With LTSpice | Dave Rowntree | [
"Software Hacks"
] | [
"bootstrapping",
"LTSpice",
"power supplies",
"simulation"
] | LTSpice is a tool that every electronics nerd should have at least a basic knowledge of. Those of us who work professionally in the analog and power worlds rely heavily on the validity of our simulations. It’s one of the basic skills taught at college, and essential to truly understand how a circuit behaves. [Mano] has quite a collection of videos about the tool, and
here is a great video explanation of how a bootstrap circuit works
, enabling a high-side driver to work in the context of driving a simple buck converter. However, before understanding what a bootstrap is, we need to talk a little theory.
Bootstrap circuits are very common when NMOS (or NPN) devices are used on the high side of a switching circuit, such as a half-bridge (and by extension, a full bridge) used to drive a motor or pump current into a power supply.
A simple half-bridge driving illustrates the high-side NMOS driving problem.
From a simplistic viewpoint, due to the apparent symmetry, you’d want to have an NMOS device at the bottom and expect a PMOS device to be at the top. However, PMOS and PNP devices are weaker, rarer and more expensive than NMOS, which is all down to the device physics; simply put, the hole mobility in silicon and most other semiconductors is much lower than the electron mobility, which results in much less current. Hence, NMOS and NPN are predominant in power circuits.
As some will be aware, to drive a high-side switching transistor, such as an NPN bipolar or an NMOS device, the source end will not be at ground, but will be tied to the switching node, which for a power supply is the output voltage. You need a way to drive the gate voltage in excess of the source or emitter end by at least the threshold voltage. This is necessary to get the device to fully turn on, to give the lowest resistance, and to cause the least power dissipation. But how do you get from the logic-level PWM control waveform to what the gate needs to switch correctly?
The answer is to use a so-called bootstrap capacitor. The idea is simple enough: during one half of the driving waveform, the capacitor is charged to some fixed voltage with respect to ground, since one end of the capacitor will be grounded periodically. On the other half cycle, the previously grounded end, jumps up to the output voltage (the source end of the high side transistor) which boosts the other side of the capacitor in excess of the source (because it got charged already) providing a temporary high-voltage floating supply than can be used to drive the high-side gate, and reliably switch on the transistor. [Mano] explains it much better in a practical scenario in the video below, but now you get the why and how of the technique.
We see videos about LTSpice quite a bit,
like this excellent YouTube resource
by [FesZ] for starters. | 14 | 6 | [
{
"comment_id": "8127066",
"author": "RetepV",
"timestamp": "2025-05-13T08:37:32",
"content": "As a motorbike rider, I try to avoid low side and high side driving as the plague. :DBut this is what Hackaday is doing for me: as (digital) computer scientist, I am gradually learning about analog electro... | 1,760,371,546.98917 | ||
https://hackaday.com/2025/05/12/the-zx-spectrum-logic-analyzer/ | The ZX Spectrum Logic Analyzer | Al Williams | [
"Raspberry Pi",
"Retrocomputing"
] | [
"logic analyzer",
"pi pico",
"rp2040",
"Spectrum ZX"
] | We know [Happy Little Diodes] frequently works with logic analyzer projects. His recent
wireless logic analyzer for the ZX Spectrum
is one of the oddest ones we’ve seen in a while. The heart of the system is an RP2040, and there are two boards. One board interfaces with the computer, and another hosts the controller.
The logic analyzer core is powered by a common
open-source analyzer
from [Eldrgusman]. This is one of the nice things about open source tools. Most people probably don’t need a logic analyzer that plugs directly into a ZX Spectrum. But if you do, it is fairly simple to repurpose a more generic piece of code and rework the hardware, if necessary.
You used to pay top dollar to get logic analyzers that “knew” about common CPUs and could capture their bus cycles, show execution, and disassemble the running code. But using a technique like this, you could easily decode any processor, even one you’ve designed yourself. All you need to do is invest the time to build it, if no one else has done it yet.
[Happy Little Diodes] is a
big fan of the [Eldrgusman] design
. What we would have given for a logic analyzer like this
forty years ago
. | 8 | 4 | [
{
"comment_id": "8127040",
"author": "Nikolai",
"timestamp": "2025-05-13T07:11:01",
"content": "I was thinking to use ECG (EKG) as a logic analyzer. I have collected some ECG parts from surplus. It is technically a logic analyzer already, but kinda expensive if you look at original price.",
"par... | 1,760,371,547.219024 | ||
https://hackaday.com/2025/05/12/a-single-pixel-camera-without-moving-parts-using-compressed-sensing/ | A Single-Pixel Camera Without Moving Parts Using Compressed Sensing | Maya Posch | [
"digital cameras hacks",
"Science"
] | [
"compressed sensing",
"single pixel camera"
] | One of the reconstructed images, using all 4,096 matrix patterns as input, next to the original object. (Credit: okooptics, Jon Bumstead)
There’s a strange allure to single-pixel cameras due to the simultaneous simplicity and yet fascinating features that they can offer, such as no set resolution limit. That said, the typical implementations that use some kind of scanning (MEMS) mirror or similar approach suffer from various issues even when you’re photographing a perfectly stationary and static scene due to their complex mechanical nature. Yet there’s a way around this, involving a LED matrix and a single photoresistor, as covered by [Jon Bumstead]
in an article
with
accompanying video
.
As he points out, this isn’t a new concept, with research papers cited that go back many years. At the core lies the signal processing technique called
compressed sensing
, which is incidentally also used with computed tomography (CT) and magnetic resonance imaging (MRI) scanners. Compressed sensing enables the reconstruction of a signal from a series of samples, by using existing knowledge of the signal.
In the case of this single-pixel camera, the known information is the illumination, which is a
Hadamard matrix
pattern displayed on the 64 x 64 pixel LED matrix, ergo 4,096 possible patterns. A total of 4,096 samples are thus recorded, which are subsequently processed with a Matlab script. As pointed out, even 50% of the maximum possible matrices can suffice here, with appropriately chosen patterns.
While not an incredibly fast method, it is fully solid-state, can be adapted to use other wavelengths, and with some tweaking of the used components probably could cut down the sampling time required. | 18 | 7 | [
{
"comment_id": "8127012",
"author": "Ject",
"timestamp": "2025-05-13T02:53:46",
"content": "I would like to have seen him try illuminating 1 pixel at a time, and just assign the photodetector value to the corresponding pixel. That’s less time efficient than using the patterns, but I think it would... | 1,760,371,547.34225 | ||
https://hackaday.com/2025/05/12/work-eat-sleep-repeat-become-a-human-tamagotchi/ | Work, Eat, Sleep, Repeat: Become A Human Tamagotchi | Heidi Ulrich | [
"Games",
"News",
"Toy Hacks"
] | [
"dystopia",
"led",
"led matrix",
"maslow",
"pixel",
"python",
"raspberry pi",
"tamagotchi"
] | When [Terence Grover] set out to build a Tamagotchi-inspired simulator,
he didn’t just add a few modern tweaks.
He ditched the entire concept and rebuilt it from the ground up. Forget cute wide-eyed blobby animals and pixel-poop. This Raspberry Pi-powered project ditches nostalgia in favour of brutal realism: inflation, burnout, capitalism, and the occasional existential crisis. Think Sims meets cyberpunk, rendered charmingly in Python on a low-res RGB LED matrix.
Instead of hunger and poop meters, this dystopian pet juggles Maslow’s hierarchy: hunger, rest, safety, social life, esteem, and money. Players make real-life-inspired decisions like working, socialising, and going into education – each affecting the stats in logical (and often unfair) ways. No free lunch here: food requires money, money requires mind-numbing labour, and labour tanks your rest. You can even die of
overwork à la Amazon warehouse
. The UI and animation logic are all hand-coded, and there’s a working buzzer, pixel-perfect sprite movement, and even mini-games to simulate job repetition.
It’s equal parts social commentary and pixel art fever dream. While we have covered
Tamagotchi recreations
some time ago, this one makes you the needy survivor. Want your own dystopia in 64×32? Head over to
[Terence Grover]’s Github
and fork the full open source code. We’ll be watching. The Tamagotchi certainly is. | 10 | 7 | [
{
"comment_id": "8127030",
"author": "jpa",
"timestamp": "2025-05-13T05:50:09",
"content": "From the title I expected this to be an AI that gives you the commands that you would give to a Tamagotchi. No more deciding things yourself!",
"parent_id": null,
"depth": 1,
"replies": []
},
... | 1,760,371,547.389942 | ||
https://hackaday.com/2025/05/12/unwinding-an-unusual-slide-rule/ | Unwinding An Unusual Slide Rule | Al Williams | [
"Retrocomputing"
] | [
"otis king",
"slide rule"
] | If the
Otis King slide rule
in [Chris Staecker’s] latest video looks a bit familiar, you might be getting up there in age, or you might remember seeing us talk about one
in our collection
. Actually, we have two floating around one of the Hackaday bunkers, and they are quite the conversation piece. You can watch the video below.
The device is often mistaken for a spyglass, but it is really a huge slide rule with the scale wrapped around in a rod-shaped form factor. The video says the scale is the same as a 30-inch scale, but we think it is closer to 66 inches.
Slide rules work using the idea that adding up logarithms is the same as multiplying. For example, for a base 10 logarithm, log(10)=1, log(100)=2, and log(1000)=3. So you can see that 1+2=3. If the scales are printed so that you can easily add and then look up the antilog, you can easily figure out that 10×100=1000.
The black center part acts like a cursor on a conventional slide rule. How does it work? Watch [Chris’] video and you’ll see. We know from experience that one of these in good shape isn’t cheap. Lucky that [Chris] gives us a
3D printed version
so you can make your own.
Another way to reduce the scale is to go
circular
, and you can make one of those, too. | 15 | 9 | [
{
"comment_id": "8126979",
"author": "Tom G",
"timestamp": "2025-05-12T22:00:57",
"content": "Ah, the diddy pocket slide rule. Why not get a “full-size” one?The Fuller calculator has a scale that is nominally[1] equivalent to a 1000inch/25.4m scale standard straight slide rule. Over 14000 were made... | 1,760,371,547.445623 | ||
https://hackaday.com/2025/05/14/your-own-core-rope-memory/ | Your Own Core Rope Memory | Al Williams | [
"Retrocomputing"
] | [
"core memory",
"Core rope memory",
"magnetics",
"memory"
] | If you want read-only memory today, you might be tempted to use flash memory or, if you want old-school, maybe an EPROM. But there was a time when that wasn’t feasible. [Igor Brichkov] shows us how to
make a core rope memory
using a set of ferrite cores and wire. This was famously used in early UNIVAC computers and the Apollo guidance computer. You can see how it works in the video below.
While rope memory superficially resembles core memory, the principle of operation is different. In core memory, the core’s magnetization is what determines any given bit. For rope memory, the cores are more like a sensing element. A set wire tries to flip the polarity of all cores. An inhibit signal stops that from happening except on the cores you want to read. Finally, a sense wire weaves through the cores and detects a blip when a core changes polarity. The second video, below, is an old MIT video that explains how it works (about 20 minutes in).
Why not just use core memory? Density. These memories could store much more data than a core memory system in the same volume. Of course, you could write to core memory, too, but that’s not always a requirement.
We’ve seen a resurgence of
core rope projects
lately. Regular
old core
is fun, too. | 14 | 8 | [
{
"comment_id": "8127843",
"author": "Carl Breen",
"timestamp": "2025-05-14T20:05:04",
"content": "https://hackaday.com/2022/01/13/soviet-era-auto-dialler-uses-magnetic-rope-core-memory/Probably the best use that existed in civil applications you could actually buy.",
"parent_id": null,
"dep... | 1,760,371,547.494765 | ||
https://hackaday.com/2025/05/14/2025-pet-hacks-contest-automatic-treat-dispenser-makes-kitty-work-for-it/ | 2025 Pet Hacks Contest: Automatic Treat Dispenser Makes Kitty Work For It | Tyler August | [
"contests",
"home hacks"
] | [
"2025 Pet Hacks Contest",
"cat wheel",
"continuous rotation servo",
"ESP32 wroom",
"treat dispenser"
] | Treat dispensers are old hat around here, but what if kitty doesn’t need the extra calories — and actually needs to drop some pounds? [MethodicalMaker] decided to
link the treat dispenser to a cat wheel, and reward kitty for healthy behaviors
. The dispenser can be programmed to make the cat run long enough to burn the calories of its treat. Over time, kitty can be trained to run longer between treats to really melt off the pounds.
The wheel itself is an off the shelf model called “One Fast Cat”; apparently these are quite cheap second hand as most cats don’t really see the point in exercise. [MethodicalMaker] glued evenly-spaced magnets along the rim in order to track the rotation with a hall effect sensor. A microcontroller is watching said sensor, and is programmed to release the treats after counting off a set number of revolutions. Control over the running distance and manual treat extrusion is via web portal, but the networking code had difficulty on the Arduino R4 [MethodicalMaker] started with, so he switched to an ESP32 to get it working.
The real interesting part of this project is the physical design of the treat dispenser: it uses a double-auger setup to precisely control treat release. The first auger lives inside a hopper that holds a great many treats, but it tended to over-dispense so [MethodicalMaker] methodically made a second auger that sits beneath the hopper. The handful of treats extruded by the first auger are dispensed individually by the second auger, aided by a photosensor inside the exit chute to count treats. This also lets the machine signal when it needs refilling. For precise control, continuous servos are used to drive the augers. Aside from the electronics, everything is 3D printed; the
STLs are on Printables
, and the
code is on GitHub
.
If you don’t have a cat wheel,
DIY is an option
. If you don’t have a cat, we’ve also
highlighted dog treat dispensers
. If you don’t have either, check with your local animal shelter; we bet good money there are oodles ready to adopt in your town, and then you’ll have an excuse to
enter one of your projects into our ongoing Pet Hacks Contest
. | 10 | 7 | [
{
"comment_id": "8127810",
"author": "Hirudinea",
"timestamp": "2025-05-14T19:05:31",
"content": "Make it human sized and dispense donuts and you have the next new fitness fad.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8127852",
"author": "Tyler... | 1,760,371,547.547714 | ||
https://hackaday.com/2025/05/14/rtems-statement-deepens-libogc-license-controversy/ | RTEMS Statement Deepens Libogc License Controversy | Tom Nardi | [
"Current Events",
"Featured",
"Nintendo Wii Hacks",
"Slider",
"Software Development"
] | [
"gamecube",
"homebrew",
"libogc",
"nintendo",
"RTEMS",
"software license",
"wii"
] | Earlier this month
we covered the brewing controversy over libogc
, the community-developed C library that functions as the backbone for GameCube and Wii homebrew software. Questions about how much of the library was based on leaked information from Nintendo had been circulating for decades, but the more recent accusations that libogc included code from other open source projects without proper attribution brought the debate to a head — ultimately leading Wii Homebrew Channel developer Hector Martin to archive the popular project and use its README as a central point to collect evidence against libogc and its developers.
At the time, most of the claims had to do with code being taken from the Real-Time Executive for Multiprocessor Systems (RTEMS) project. Martin and others in the community had performed their own investigations, and found some striking similarities between the two codebases. A developer familiar with both projects went so far as to say that as much as half the code in libogc was actually lifted from RTEMS and obfuscated so as to appear as original work.
While some of these claims included compelling evidence, they were still nothing more than accusations. For their part, the libogc team denied any wrongdoing. Contributors to the project explained that any resemblance between libogc code and that of either leaked Nintendo libraries or other open source projects was merely superficial, and the unavoidable result of developing for a constrained system such as a game console.
But that all changed on May 6th, when the
RTEMS team released an official statement on the subject
. It turns out that they had been following the situation for some time, and had conducted their own audit of the libogc code. Their determination was that not only had RTEMS code been used without attribution, but that it appeared at least some code had also been copied verbatim from the Linux kernel — making the license dispute (and its solution) far more complex.
Permissive vs Restrictive
At first glance, this all might seem like something of a non-issue. After all, libogc, RTEMS, and the Linux kernel are all open source projects. Surely, the point of releasing these projects as open source in the first place was to facilitate and even encourage the sharing of source code. In a sense, this could be looked at as the system working as intended.
Indeed, it’s not the reuse of code that’s really the issue here. The problem stems from the licenses by which the respective projects have made their source code available, and more specifically, how well those licenses integrate with each other.
When the complaint was that libogc was using large swaths of code from RTEMS, the path towards compliance was simple as latter project was released under what’s known as a permissive license, namely, the
2-Clause BSD License
. As the name implies, permissive licenses such as this give the user broad rights on how they can reuse the code
For example, one could take BSD-licensed code, merge it as-is into a closed source project, and sell the resulting software for profit without violating the license. All the original project asks in return is that you give proper attribution. In this case, that means acknowledging you used code from said project in the documentation, and including a copy of the license.
Returning to libogc, the issue at hand could be resolved with a single commit to the project’s GitHub repository. A simple notice that the project used code from RTEMS and a copy of the BSD license is all it would take to satisfy the requirements. That the libogc developers will not make even such a simple concession in the face of overwhelming evidence that they did indeed reuse code is frankly indefensible; a sentiment expressed in the statement from the RTEMS developers:
RTEMS is open source and this means RTEMS can be copied and used as long as the license conditions are met and copyright is maintained. We are at a loss why there has been removal of license details and copyright and a general disregard to apply appropriate attributions. As a result the RTEMS license and copyright holders reserve their rights in relation to the copying of RTEMS code.
That being said, the revelation that libogc would appear to include code from the Linux kernel complicates matters considerably. Unlike RTEMS, Linux is licensed under the GPL v2 — a license that is not only far more restrictive, but viral in nature.
The Case for Kernel Code
It’s that viral aspect of the license that promises to give libogc the most trouble. If they did indeed use code from the Linux kernel, that would mean there are only two solutions. Either the offending code must be removed, or the entire project will need to be re-licensed under the GPL v2.
For a codebase as old as libogc, changing the license would be a massive undertaking, as every person who’s added code to the project would have to agree to have their individual contribution re-licensed. The libogc repository lists dozens of contributors, and that’s only since project was added to GitHub. As there appears to be no
CREDITS
file that lists the contributions before the advent of Git, there may be no way to know at this point how many contributors there actually are and what they added.
So the question of whether or not libogc uses Linux code is going to be critical to determining how the project moves forward. The RTEMS statement doesn’t go into great detail about this claim, simply stating that the “spinlock implementation is copied directly from Linux circa 2.4 or 2.6 release series.” Sure enough, when comparing the file
spinlock.h
file from the latest version of libogc to
linux-2.6.0/include/asm-ppc/spinlock.h
there are indeed functions which are nearly identical:
That said, this may not be as damning as it seems. To play Devil’s advocate, one could argue that the terse nature of assembly code means that a certain level of similarity is unavoidable between the two implementations. Of course, convention can only get you so far. It’s one thing to independently arrive at the same assembly code, but this explanation becomes harder to believe when you consider the identical variable names and comments.
What’s Next?
As of this writing, the libogc project has not made an official statement on the situation. We reached out to maintainer Dave [WinterMute] Murphy before going to press with this article, but he declined to comment, saying that he first needed to confer with the original developer of the library, Michael [shagkur] Wiedenbauer.
At the same time, our contacts within the RTEMS project have indicated they believe they have sufficient evidence to have libogc removed from GitHub if necessary. However, they’re understandingly hesitant to disrupt the Wii homebrew community over an issue that could ultimately be resolved with a simple discussion. While the potential use of Linux code does add a considerable wrinkle to the overall situation, if the libogc project would at least acknowledge the use of RTEMS code and properly attribute it after all these years, it would at least be a step in the right direction.
We’ll continue to keep an eye on the situation, and bring you updates as we have them. In the meantime, we think the final line of the RTEMS statement nicely summarizes the biggest takeaway from this whole mess:
Our goal now is to provide education on how the behavior engaged in by the devkitPro/libOGC project is a very good example of what
not
to do. | 41 | 11 | [
{
"comment_id": "8127791",
"author": "jpa",
"timestamp": "2025-05-14T18:21:39",
"content": "Relicensing libogc from permissive license to GPL shouldn’t be that much of a trouble. It may be more difficult for projects depending on it.The similarity to linux 2.4.10 spinlock.h is almost 100%. And becau... | 1,760,371,547.632514 | ||
https://hackaday.com/2025/05/14/raduga-the-retro-computer-from-behind-the-curtain/ | RADUGA: The Retro Computer From Behind The Curtain | Al Williams | [
"Retrocomputing"
] | [
"USSR",
"z80"
] | When [Kasyan] was six years old, he saw a
RADUGA computer
, a Russian unit from the 1990s, and it sparked his imagination. He has one now that is a little beat up, but we feel like he sees it through his six-year-old eyes as a shiny new computer. The computer, which you can see in the video below, was a clone of the Spectrum 48K.
The box is somewhat klunky-looking, and inside is also a bit strange. The power supply is a — for the time — state-of-the-art switching power supply. Since it wasn’t in good shape, he decided to replace it with a more modern supply.
The main board was also not in good shape. A Zilog CPU is on a large PCB with suspicious-looking capacitors. The mechanical keyboard is nothing more than a array of buttons, and wouldn’t excite today’s mechanical key enthusiast.
The computer isn’t working yet. [Kasyan] is looking for someone who has the exact schematic, although he’s found a similar one and identified at least some of the problems on the board.
The USSR did a lot of
work with early computing
, but we don’t hear as much about it. That’s surprising, as they had a very active
home computer scene
. | 7 | 5 | [
{
"comment_id": "8127740",
"author": "Joshua",
"timestamp": "2025-05-14T16:26:02",
"content": "Wonderful machine! 😃💙These computer designs have something retro futuristic to them, I think.The only thing I don’t really understand why they did bother to support color.I mean, IBM’s CGA and the ZX Spe... | 1,760,371,547.673442 | ||
https://hackaday.com/2025/05/14/version-control-to-the-max/ | Version Control To The Max | Al Williams | [
"Featured",
"Rants",
"Slider",
"Software Development"
] | [
"Rant",
"version control",
"virtualization"
] | There was a time when version control was an exotic idea. Today, things like Git and a handful of other tools allow developers to easily rewind the clock or work on different versions of the same thing with very little effort. I’m here to encourage you not only to use version control but also to go even a step further, at least for important projects.
My First Job
The QDP-100 with — count ’em — two 8″ floppies (from an ad in Byte magazine)
I remember my first real job back in the early 1980s. We made a particular type of sensor that had a 6805 CPU onboard and, of course, had firmware. We did all the development on physically big CP/M machines with the improbable name of Quasar QDP-100s. No, not that
Quasar
. We’d generate a hex file, burn an EPROM, test, and eventually, the code would make it out in the field.
Of course, you always have to make changes. You might send a technician out with a tube full of EPROMs or, in an emergency, we’d buy the EPROMs space on a Greyhound bus. Nothing like today.
I was just getting started, and the guy who wrote the code for those sensors wasn’t much older than me. One day, we got a report that something was misbehaving out in the field. I asked him how we knew what version of the code was on the sensor. The blank look I got back worried me.
Seat of the Pants
Version control circa 1981 alongside a 3.5-inch floppy that held much more data
Turns out, he’d burn however many EPROMs were required and then plow forward developing code. We had no idea what code was really running in the field. After we fixed the issue, I asked for and received a new rule. Every time we shipped an EEPROM, it got a version number sticker, and the entire development directory went on an 8″ floppy. The floppy got a write-protect tab and went up on the shelf.
I was young. I realize now that I needed to back those up, too, but it was still better than what we had been doing.
Enter Meta Version Control
Today, it would have been easy to label a commit and, later, check it back out. But there is still a latent problem. Your source code is only part of the equation when you are writing code. There’s also your development environment, including the libraries, the compiler, and anything else that can add to or modify your code. How do you version control that? Then there’s the operating system, which could interact with your code or development tools too.
Maybe it is a call back to my 8″ floppy days, but I have taken to doing serious development in a virtual machine. It doesn’t matter if you use QEMU or VirtualBox or VMWare. Just use it. The reason is simple. When you do a release, you can backup the entire development environment.
When you need to change something five years from now, you might find the debugger no longer runs on your version of the OS. The compiler fixed some bugs that you rely on or added some that you now trip over. But if you are in your comfy five-year-old virtual environment, you won’t care. I’ve had a number of cases where I wish I had done that because my old DOS software won’t run anymore. Switched to Linux? Or NewOS 2100
tm
? No problem, as long as it can host a virtual machine.
Can’t decide on which one to use? [How to Simple] has some thoughts in the video below.
How About You?
How about it? Do you or will you virtualize and save? Do you use containers for this sort of thing? Or do you simply have faith that your version-controlled source code is sufficient? Let us know in the comments.
If you think Git is just for software,
think again
. | 42 | 20 | [
{
"comment_id": "8127687",
"author": "jens",
"timestamp": "2025-05-14T14:17:05",
"content": "We use docker / podman containers that contain all the environment including external code and libraries which obviously could also disappear in the future.The docker file can be versioned as well, the resul... | 1,760,371,547.967746 | ||
https://hackaday.com/2025/05/14/a-brain-transplant-for-a-philips-smart-lamp/ | A Brain Transplant For A Philips Smart Lamp | Tyler August | [
"home hacks",
"Microcontrollers"
] | [
"ESP32-C6",
"smart light",
"zigbee"
] | As the saying goes, modern problems require modern solutions. When the modern problem is that your smart light is being hijacked by the neighbors, [Wejn]’s modern solution is to
reverse engineer and replace the mainboard.
The light in question is a Phillips Hue Ambiance, and [Wejn]’s excellently-documented six part series takes us through the process of creating a replacement light driver. It’s a good read, including reverse-engineering the PWM functions to get the lights to dim exactly like stock, and a dive into the Zigbee protocol so his rebuild light could still talk to the Philips Hue hub. The firmware [Wejn] wrote for the ESP32C6 he chose to use for this
project is on GitHub
, with the
PCB in a second repo
.
We want to applaud [Wejn] for his excellent documentation and open-sourcing (the firmware and PCB are under GPL v3). Not only do we get enough information to replicate this project perfectly if we so choose, but by writing out his design process, [Wejn] gives everyone reading a good head start in doing something similar with other hardware. Even if you’re scratching your head wondering why a light switch isn’t good enough anjymore, you have to appreciate what [Wejn] is offering the community.
We’ve covered domestic brain transplants in the past — which is easier in this sort of light than the
close confines of a smart bulb
. If you’re still wondering why not just use a light switch, perhaps you’d rather
hack the light to run doom instead
.
Before you go, can we just take a moment to appreciate how bizarre the world has become that we have a
DOOM
-capable computer to run fancy light fixture? If you’re using what might have been a decent workstation in days of yore to perform a painfully mundane task,
let us know on the tips line. | 25 | 8 | [
{
"comment_id": "8127617",
"author": "Jan",
"timestamp": "2025-05-14T11:19:25",
"content": "“Even if you’re scratching your head wondering why a light switch isn’t good enough anymore…”Ahh… you’ve read my mind. This is scary…“smart light is being hijacked by the neighbors”What… that’s even scarier!B... | 1,760,371,547.883557 | ||
https://hackaday.com/2025/05/14/turning-a-chromebox-into-a-proper-power-efficient-pc/ | Turning A Chromebox Into A Proper Power-Efficient PC | Maya Posch | [
"computer hacks",
"google hacks"
] | [
"chromebox",
"ChromeOS"
] | Google’s ChromeOS and associated hardware get a lot of praise for being easy to manage and for providing affordable hardware for school and other educational settings. It’s also undeniable that their locked-down nature forms a major obstacle and provides limited reusability.
That is unless you don’t mind doing a bit of hacking. The Intel Core i3-8130U based Acer CXI3 Chromebox that the
[Hardware Haven] YouTube channel got their mittens
on is a perfect example.
The Acer CXI3 in all its 8th-gen Intel Core i3 glory. (Credit: Hardware Haven, YouTube)
This is a nice mini PC, with modular SODIMM RAM, an NVMe storage M.2 slot as well as a slot for the WiFi card (or SATA adapter). After resetting the Chromebox to its default configuration and wiping the previous user, it ran at just a few watts idle at the desktop. As this is just a standard x86_64 PC, the only thing holding it back from booting non-ChromeOS software is the BIOS, which is where
[MrChromebox]
‘s exceedingly useful replacement BIOSes for supported systems come into play, with
easy to follow instructions
.
Reflashing the Acer CXI3 unit was as easy as removing the write-protect screw from the mainboard,
running the Firmware Utility Script
from a VT2 terminal (
Ctrl+Alt+F2
on boot and
chronos
as login) and flashing either the RW_LEGACY or UEFI ROM depending on what is
supported
and desired. This particular Chromebox got the full UEFI treatment, and after upgrading the NVMe SSD, Debian-based Proxmox installed without a hitch. Interestingly, idle power dropped from 2.6 watts under ChromeOS to 1.6 watts under Proxmox.
If you have a Chromebox that’s supported by [MrChromebox], it’s worth taking a poke at, with some solutions allowing you to even dualboot ChromeOS and another OS if that’s your thing. | 21 | 7 | [
{
"comment_id": "8127561",
"author": "shinsukke",
"timestamp": "2025-05-14T08:31:55",
"content": "Great, now I want it too! (I have no use for it, I already have a ryzen 5 3550H server running 24/7)",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8127592",
... | 1,760,371,548.094419 | ||
https://hackaday.com/2025/05/12/semiconductor-simulator-lets-you-play-ic-designer/ | Semiconductor Simulator Lets You Play IC Designer | Al Williams | [
"Software Hacks",
"Tool Hacks"
] | [
"IC design",
"semiconductor",
"simulator"
] | For circuit simulation, we have always been enthralled with the Falstad simulator which is a simple, Spice-like simulator that runs in the browser. [Brandon] has a simulator, too, but it simulates semiconductor devices. With help from [Paul Falstad], that
simulator also runs in the browser
.
This simulator takes a little thinking and lets you build devices as you might on an IC die. The key is to use the drop-down that initially says “Interact” to select a tool. Then, the drop-down below lets you select what you are drawing, which can be a voltage source, metal, or various materials you find in semiconductor devices, like n-type or a dielectric.
It is a bit tricky, but if you check out the examples first (like this
diode
), it gets easier. The main page has many examples. You can even build up entire subsystems like a ring oscillator or a DRAM cell.
Designing at this level has its own quirks. For example, in the real world, you think of resistors as something you can use with great precision, and capacitors are often “sloppy.” On an IC substrate, resistors are often the sloppy component. While capacitor values might not be exact, it is very easy to get an extremely precise ratio of two capacitors because the plate size is tightly controlled. This leads to a different mindset than you are used to when designing with discrete components.
Of course, this is just a simulation, so everything can be perfect. If, for some reason, you don’t know about the Falstad simulator,
check it out now
. | 8 | 4 | [
{
"comment_id": "8126964",
"author": "Steven Clark",
"timestamp": "2025-05-12T19:18:42",
"content": "Sothat’swhy the DAC in Successive-Approximation-Register ADCs is a C2C instead of R2R ladder.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8126971",
"aut... | 1,760,371,548.190316 | ||
https://hackaday.com/2025/05/12/keebin-with-kristina-the-one-with-the-mingkwai-typewriter/ | Keebin’ With Kristina: The One With The MingKwai Typewriter | Kristina Panos | [
"Hackaday Columns",
"Peripherals Hacks",
"Slider"
] | [
"endgame keyboard",
"media control",
"MingKwai typewriter",
"Munson",
"portable endgame",
"portable keyboard",
"seeed xiao",
"the Munson typewriter"
] | Sometimes, a little goes a long way. I believe that’s the case with
this tiny media control bar
from [likeablob] that uses an ESP32-C3 Super Mini.
Image by [likeablob] via
Hackaday.IO
From left to right you’ve got a meta key that allows double functions for all the other keys. The base functions are play/pause, previous track, and next track while the knob handles volume.
And because it uses this Wi-Fi-enabled microcontroller, it can seamlessly integrate with Home Assistant via ESPHome.
What else is under the hood? Four low-profile Cherry MX Browns and a rotary encoder underneath that nicely-printed knob.
If you want to build one of these for yourself,
all the files are available on GitHub
including the customizable enclosure which [likeablob] designed with OpenSCAD.
Portable Endgame, If It Exists
Perhaps [Palpatine]’s one mistake in creating
this 36-key portable endgame
is believing in the idea of the endgame in the first place. But I’m not here to judge.
Image by [Palpatine] via
reddit
Oh wait, yes I am! I really like this keyboard, and I think it would look right at home on the desk of the centerfold below it, although it’s supposed to be a go-anywhere contraption. Be sure to check out the gallery on this one to see it folded together for transport.
It would seem that [Palpatine] learned some nice tricks while designing this keyboard. Have you heard of 10440 batteries? They’re 3.7 V and usually cheaper than the square Li-Po batteries of the same size.
This bad boy is based on the Seeed Xiao nRF52840, which [Palpatine] believes is worth spending a little bit of extra money on instead of nice!nano clones, while being cheaper than an actual nice!nano would be.
As far as open-sourceness goes, [Palpatine] seems willing to share their design files, although they don’t seem to have been published anywhere at this time.
The Centerfold: White Light Might Bite At Night
Image by [Embarrased-Yak-3766] via
reddit
So this one isn’t quite as wide as usual, but it’s definitely more white than usual
. I suppose that wiiiide monitor makes up for the missing pixels.
What do you think? Crisp and clean, or cold and clinical? I can’t decide. I definitely feel snowbound vibes, and I want to sleep in.
Do you rock a sweet set of peripherals on a screamin’ desk pad?
Send me a picture
along with your handle and all the gory details, and you could be featured here!
Historical Clackers: the Munson
Image by [Martin Howard] via
Antique Typewriters
The delight of
the Munson typewriter
is in the exposed internal workings, which come to life when the machine is in use. Those octagonal key tops aren’t too shabby, either.
You may have noticed that this machine has no typebars. Instead, it uses a horizontal cylinder about the size of a finger. The cylinder slides from side to side and rotates to find the chosen character. Then a hammer strikes from behind the paper, pushing it against the ribbon and the type cylinder.
Much like the later IBM Selectrics and the daisy wheel machines of the 1970s and ’80s, one could easily change the font by swapping out the all-steel type cylinder. The Munson has two Shift keys, one for upper case and another for figures, so only three rows of keys are needed.
The Munson came out in 1890 and was well-received. It won the highest medal awarded at the World’s Fair Chicago, 1893, but the machines are hard to find these days. Eight years after its introduction, the design of the Munson was acquired by the Chicago Writing Machine Co. and rebranded the Chicago.
Finally, the MingKwai Typewriter Emerges From Obscurity
So you get a Historical Clackers two-fer this week; lucky you! After more than half a century,
this fascinating Chinese typewriter
turned up while a couple was cleaning out her grandfather’s basement in New York.
Jennifer Felix and her husband Nelson posted photos on a Facebook group trying to ID the machine. A flurry of enthusiastic comments flooded the forum, with many people offering to buy the machine.
Photo by Elisabeth von Boch, courtesy of Stanford Libraries; image via
This Is Colossal
As it turns out, it’s a MingKwai — the only one in existence. And it’s now in the hands of Stanford Libraries.
This machine was invented in 1947 by a writer, translator, and linguist named Lin Yutang. The MingKwai, which means “clear and fast”, was the first compact concept Chinese typewriter to have a keyboard that was capable of producing 80,000+ characters.
How is that even possible? Mechanical sort and search. Seriously! Check this out: the 72-key board is made up of strokes and shapes, and the characters are arranged in linear order, like an English dictionary. To use it, you would press one of the 36 top keys and one of the 28 bottom keys simultaneously. This triggered a series of rotations in the internals and would bring eight characters into view in a small window that Lin called the “magic eye”. Finally, you would choose your desired character using the numbered keys in the bottom row.
The only known prototype was built by the Carl E. Krum company. Lin was unable to drum up commercial interest to produce it at scale, so he sold the rights and the prototype to Mergenthaler Linotype Company, where Jennifer Felix’s grandfather worked as a machinist. So it never went into production, and the prototype went home with with Grandpa.
Got a hot tip that has like, anything to do with keyboards?
Help me out by sending in a link or two
. Don’t want all the Hackaday scribes to see it? Feel free to
email me directly
. | 4 | 4 | [
{
"comment_id": "8126928",
"author": "JRD",
"timestamp": "2025-05-12T17:41:29",
"content": "That whiteout station would fit in the film THX-1138. Imagine an endless white void with a desk far in the distance, and as you get closer you see a white desk with an all-white computer, with one lone guy we... | 1,760,371,548.147259 | ||
https://hackaday.com/2025/05/12/print-pla-in-pla-with-a-giant-molecular-model-kit/ | Print PLA In PLA With A Giant Molecular Model Kit | Tyler August | [
"chemistry hacks"
] | [
"3D printable",
"Chemistry",
"educational toy",
"molecule"
] | It isn’t too often we post a hack that’s just a pure 3D print with no other components, but for this
Giant Molecular Model kit
by [3D Printy], we’ll make an exception. After all, even if you print with PLA every day, how often do you get to play with its molecular bonds? (If you want to see that molecule, check out the video after the break.)
There are multiple sizes of bonds to represent bond lengths, and two styles: flexible and firm. Flexible bonds are great for multiple covalent bonds, like carbon-carbon bonds in organic molecules. The bonds clip to caps that screw in to the atoms; alternately a bond-cap can screw the atoms together directly. A plethora of atoms is available, in valence values from one to four. The two-bond atom has 180 and 120-degree variations for greater accuracy. In terms of the chemistry this kit could represent, you’re only limited by your imagination and how long you are willing to spend printing atoms and bonds.
[3D Printy] was kind enough to release the whole lot as CC0 Public Domain, so we might be seeing these at craft fairs, as there’s nothing to keep you from selling the prints. Honestly, we can only hope; from an educational standpoint, this is a much better use of plastic than endless flexy dragons.
If you’d prefer your chemistry toys help you do chemistry, try
this fidget spinner centrifuge.
Perhaps you’d rather be
teaching electronics instead? | 1 | 1 | [
{
"comment_id": "8126986",
"author": "lightislight",
"timestamp": "2025-05-12T22:43:24",
"content": "Print quality on those is pretty great! These things are surprisingly expensive to buy. It brings me a lot of joy to see jumbo versions freely available to download an d print at will",
"parent_i... | 1,760,371,548.307818 | ||
https://hackaday.com/2025/05/12/radio-apocalypse-meteor-burst-communications/ | Radio Apocalypse: Meteor Burst Communications | Dan Maloney | [
"Featured",
"History",
"Interest",
"Radio Hacks",
"Slider"
] | [
"burst",
"cold war",
"ion",
"ionosphere",
"meteor",
"propagation",
"radio"
] | The world’s militaries have always been at the forefront of communications technology. From trumpets and drums to signal flags and semaphores, anything that allows a military commander to relay orders to troops in the field quickly or call for reinforcements was quickly seized upon and optimized. So once radio was invented, it’s little wonder how quickly military commanders capitalized on it for field communications.
Radiotelegraph systems began showing up as early as the First World War, but World War II was the first real radio war, with every belligerent taking full advantage of the latest radio technology. Chief among these developments was the ability of signals in the high-frequency (HF) bands to reflect off the ionosphere and propagate around the world, an important capability when prosecuting a global war.
But not long after, in the less kinetic but equally dangerous Cold War period, military planners began to see the need to move more information around than HF radio could support while still being able to do it over the horizon. What they needed was the higher bandwidth of the higher frequencies, but to somehow bend the signals around the curvature of the Earth. What they came up with was a fascinating application of practical physics: meteor burst communications.
Blame It on Shannon
In practical terms, a radio signal that can carry enough information to be useful for digital communications while still being able to propagate long distances is a bit of a paradox. You can thank Claude Shannon for that, after he developed the idea of channel capacity from the earlier work of Harry Nyquist and Ralph Hartley. The resulting Hartley-Shannon Theorem states that the bit rate of a channel in a noisy environment is directly related to the bandwidth of the channel. In other words, the more data you want to stuff down a channel, the higher the frequency needs to be.
Unfortunately, that runs afoul of the physics of ionospheric propagation. Thanks to the physics of the interaction between radio waves and the charged particles between about 50 km and 600 km above the ground, the maximum frequency that can be reflected back toward the ground is about 30 MHz, which is the upper end of the HF band. Beyond that is the very-high frequency (VHF) band from 30 MHz to 300 MHz, which has enough bandwidth for an effective data channel but to which the ionosphere is essentially transparent.
Luckily, the ionosphere isn’t the only thing capable of redirecting radio waves. Back in the 1920s, Japanese physicist Hantaro Nagaoka observed that the ionospheric propagation of shortwave radio signals would change a bit during periods of high meteoric activity. That discovery largely remained dormant until after World War II, when researchers picked up on Nagoka’s work and looked into the mechanism behind his observations.
Every day, the Earth sweeps up a huge number of meteoroids; estimates range from a million to ten billion. Most of those are very small, on the order of a few nanograms, with a few good-sized chunks in the tens of kilograms range mixed in. But the ones that end up being most interesting for communications purposes are the particles in the milligram range, in part because there are about 100 million such collisions on average every day, but also because they tend to vaporize in the E-level of the ionosphere, between 80 and 120 km above the surface. The air at that altitude is dense enough to turn the incoming cosmic debris into a long, skinny trail of ions, but thin enough that the free electrons take a while to recombine into neutral atoms. It’s a short time — anywhere between 500 milliseconds to a few seconds — but it’s long enough to be useful.
A meteor trail from the annual Perseid shower, which peaks in early August. This is probably a bit larger than the optimum for MBC, but beautiful nonetheless. Source:
John Flannery
,
CC BY-ND 2.0
.
The other aspect of meteor trails formed at these altitudes that makes them useful for communications is their relative reflectivity. The E-layer of the ionosphere normally has on the order of 10
7
electrons per cubic meter, a density that tends to refract radio waves below about 20 MHz. But meteor trails at this altitude can have densities as high as 10
11
to 10
12
electrons/m
3
. This makes the trails highly reflective to radio waves, especially at the higher frequencies of the VHF band.
In addition to the short-lived nature of meteor trails, daily and seasonal variations in the number of meteors complicate their utility for communications. The rotation of the Earth on its axis accounts for the diurnal variation, which tends to peak around dawn local time every day as the planet’s rotation and orbit are going in the same direction and the number of collisions increases. Seasonal variations occur because of the tilt of Earth’s axis relative to the plane of the ecliptic, where most meteoroids are concentrated. More collisions occur when the Earth’s axis is pointed in the direction of travel around the Sun, which is the second half of the year for the northern hemisphere.
Learning to Burst
Building a practical system that leverages these highly reflective but short-lived and variable mirrors in the sky isn’t easy, as shown by several post-war experimental systems. The first of these was attempted by the National Bureau of Standards in 1951. They set up a system between Cedar Rapids, Iowa, and Sterling, Virginia, a path length of about 1250 km. Originally built to study propagation phenomena such as forward scatter and sporadic E, the researchers noticed significant effects on their tests by meteor trails. This made them switch their focus to meteor trails, which caught the attention of the US Air Force. They were in the market for a four-channel continuous teletype link to their base in Thule, Greenland. They got it, but only just barely, thanks to the limited technology of the time. The NBS system also used the Iowa to Virginia system to study higher data rates by pointing highly directional rhombic antennas at each end of the connection at the same small patch of sky. They managed a whopping data rate of 3,200 bits per second with this system, but only for the second or so that a meteor trail happened to appear.
The successes and failures of the NBS system made it clear that a useful system based on meteor trails would need to operate in burst mode, to jam data through the link for as long as it existed and wait for the next one. The NBS tested a burst-mode system in 1958 that used the 50-MHz band and offered a full-duplex link at 2,400 bits per second. The system used magnetic tape loops to buffer data and transmitters at both ends of the link that operated continually to probe for a path. Whenever the receiver at one end detected a sufficiently strong probe signal from the other end, the transmitter would start sending data. The Canadians got in on the MBC action with their JANET system, which had a similar dedicated probing channel and tape buffer. In 1954 they established a full-duplex teletype link between Ottawa and Nova Scotia at 1,300 bits per second with an error rate of only 1.5%
In the late 1950s, Hughes developed a single-channel air-to-ground MBC system. This was a significant development since not only had the equipment gotten small enough to install on an airplane but also because it really refined the burst-mode technology. The ground stations in the Hughes system periodically transmitted a 100-bit interrogation signal to probe for a path to the aircraft. The receiver on the ground listened for an acknowledgement from the plane, which turned the channel around and allowed the airborne transmitter to send a 100-bit data burst. The system managed a respectable 2,400 bps data rate, but suffered greatly from ground-based interference for TV stations and automotive ignition noise.
The SHAPE of Things to Come
Supreme HQ Allied Powers Europe (SHAPE), NATO’s European headquarters in the mid-60s. The COMET meteor-bounce system kept NATO commanders in touch with member-nation HQs via teletype. Source:
NATO
The first major MBC system fielded during the Cold War was the Communications by Meteor Trails system, or COMET. It was used by the North Atlantic Treaty Organization (NATO) to link its far-flung outposts in member nations with Supreme Headquarters Allied Powers Europe, or SHAPE, located in Belgium. COMET took cues from the Hughes system, especially its error detection and correction scheme. COMET was a robust and effective MBC system that provided between four and eight teletype circuits depending on daily and seasonal conditions, each handling 60 words per minute.
COMET was in continuous use from the mid-1960s until well after the official end of the Cold War. By that point, secure satellite communications were nowhere near as prohibitively expensive as they had been at the beginning of the Space Age, and MBC systems became less critical to NATO. They weren’t retired, though, and COMET actually still exists, although rebranded as “Compact Over-the-Horizon Mobile Expeditionary Terminal.” These man-portable systems don’t use MBC; rather, they use high-power UHF and microwave transmitters to scatter signals off the troposphere. A small amount of the signal is reflected back to the ground, where high-gain antennas pick up the vanishingly weak signals.
Although not directly related to Cold War communications, it’s worth noting that there was a very successful MBC system fielded in the civilian space in the United States: SNOTEL.
We’ve covered this system
in some depth already, but briefly, it’s a network of stations in the western part of the USA with the critical job of monitoring the snowpack. A commercial MBC system connected the solar-powered monitoring stations, often in remote and rugged locations, to two different central bases. Taking advantage of diurnal meteor variations, each morning the master station would send a polling signal out to every remote, which would then send back the previous day’s data once a return path was opened. The system could collect data from 180 remote sites in just 20 minutes. It operated successfully from the mid-1970s until just recently, when pervasive cell technology and cheap satellite modems made the system obsolete. | 15 | 8 | [
{
"comment_id": "8126866",
"author": "Clancydaenlightened",
"timestamp": "2025-05-12T14:08:09",
"content": "Well using HF you can control a drone anywhere on the globe with as low as 10W of power given the right conditions and bandUse the ghz band via a sattlink simply for video and high bandwidth d... | 1,760,371,548.367386 | ||
https://hackaday.com/2025/05/12/whats-in-a-washer/ | What’s In A Washer? | Al Williams | [
"Misc Hacks"
] | [
"Belleville washer",
"washers"
] | Some things are so common you forget about them. How often do you think about an ordinary resistor, for example? Yet if you have a bad resistor, you’ll find it can be a big problem. Plus, how can you really understand electronics if you don’t know all the subtle details of a resistor? In the mechanical world, you could make the same arguments about
the washer
, and [New Mind] is ready to explain the history and the gory details of using washers in a recent video that you can see below.
The simple answer is that washers allow a bolt to fit in a hole otherwise too large, but that’s only a small part of the story. Technically, what you are really doing is distributing the load of a threaded fastener. However, washers can also act as spacers or springs. Some washers can lock, and some indicate various things like wear or preloading conditions.
Plain washers have a surprising number of secondary functions. Spring washers, including
Belleville washers
, help prevent fasteners from loosening over time. Wave washers look — well — wavy. They provide precise force against the bolt for preloading. Locking washers are also made to prevent fasteners from loosening, but use teeth or stops instead of springs.
There are plenty of standards, of course, that mostly match up. Mostly.
If you like knowing about odd washers, you might also want to know about
the bolts
that pass through them. | 15 | 7 | [
{
"comment_id": "8126823",
"author": "Fiteboss",
"timestamp": "2025-05-12T12:03:11",
"content": "Really never expected to see a photo of a machine tool drawbar on Hackaday.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8126843",
"author": "Kman",
"tim... | 1,760,371,548.418579 | ||
https://hackaday.com/2025/05/12/rebooting-an-1973-art-installation-running-on-a-nova/ | Rebooting An 1973 Art Installation Running On A Nova | Dave Rowntree | [
"Art"
] | [
"Data General Nova",
"neon lamp",
"PT8211",
"Raspberry Pi 4",
"SIMH",
"synthesiser",
"Teensy 4.0",
"ws2811"
] | Electronics-based art installations are often fleeting and specific things that only a select few people who are in the right place
or time
get to experience before they are lost to the ravages of ‘progress.’ So it’s wonderful to find a dedicated son who has recreated his father’s 1973 art installation, showing it to the world in a miniature form. The
network-iv-rebooted project
is a recreation of an installation once housed within a departure lounge in terminal C of Seattle-Tacoma airport.
You can do a lot with a ‘pi and a fistful of Teensies!
The original unit comprises an array of 1024
GE R6A neon lamps
, controlled from a Data General Nova 1210 minicomputer. A bank of three analog synthesizers also drove into no fewer than 32 resonators. An 8×8 array of input switches was the only user-facing input. The switches were mounted to a floor-standing pedestal facing the display.
For the re-creation, the neon lamps were replaced with 16×16 WS2811 LED modules, driven via a Teensy 4.0 using the
OctoWS2811 library
. The display Teensy is controlled from a Raspberry Pi 4, hooked up as a virtual serial device over USB. A second Teensy (you can’t have too many Teensies!) is responsible for scanning a miniature 8×8 push button array as well as running a simulation of the original sound synthesis setup. Audio is pushed out of the Teensy using a
PT8211 I
2
S audio DAC
, before driving a final audio power amp.
Attempting to reproduce accurately how the original code worked would be tricky, if downright impossible, but fear not, as the network-iv-rebooted
is
running the original code. Since the artist was astute enough to keep not only the engineering drawings and schematics, but also the original paper tape of the Nova 1210 program, it could be successfully run using the
SIMH Nova emulator
. The simulator needed to be modified to support the optional ‘device 76’ GPIO device added to the Nova 1210 for handling the extra connectivity. This was a small price to pay compared to the alternative. That said, most of the heavy lifting on the I/O side is performed by the pair of Teensies, with modern coding methods making life a lot easier.
Mechanics and code for the reproduction are being collected on
this GitHub repo
for those interested in building a clone. The
opus20 page
has a few photos and details of the original installation
, but many more pieces can be found on
the sculptures page
, complete with a neat video tour, which we also include below. Check out those circuit sculptures! Groovy!
We’ve
recently featured some retro electronic art
,
drooled over some circuit sculptures
, and
swooned at some PCB art
. We just can’t get enough!
A short video about James Seawright’s other pieces: | 19 | 11 | [
{
"comment_id": "8126792",
"author": "M",
"timestamp": "2025-05-12T09:33:20",
"content": "I think usagi electric is working on bringing up exactly one of those NOVA minicomputers.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126960",
"author": "mr... | 1,760,371,548.542453 | ||
https://hackaday.com/2025/05/11/simulating-cable-tv/ | Simulating Cable TV | Al Williams | [
"home entertainment hacks",
"Raspberry Pi"
] | [
"cable TV"
] | [Wrongdog Recons] suffers from a severe case of nostalgia. His earlier project simulated broadcast TV, and he was a little surprised at how popular the project was on GitHub. As people requested features, he realized that he could create a simulated cable box and
emulate a 1990s-era cable TV system
. Of course, you also needed
a physical box
, which turned into another project. You can see more about the project in the video below.
Inside is, unsurprisingly, a Raspberry Pi. Then you have to pretend to be a cable TV scheduler and organize your different video files for channels. You can interleave commercials and station breaks.
One addition was a scheduler so you could set up things like football games only play during football season. You can also control timing so you don’t get beer commercials during Saturday morning cartoons.
We were especially impressed with the program guide channel that lets you see what’s playing, just like an old-style cable system. The simulation even plays trash TV in the morning and bizarre commercials post-midnight.
If you are tired of having to decide what to watch, this might be for you. If you want to simulate the earliest pay TV,
you’ll need a coin slot
. We wonder if the simulator could do a
local origination weather channel
. | 16 | 6 | [
{
"comment_id": "8126757",
"author": "LordNothing",
"timestamp": "2025-05-12T06:10:54",
"content": "brownie points if you use fake commercials from the likes of robocop and others.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126764",
"author": "N... | 1,760,371,548.476774 | ||
https://hackaday.com/2025/05/13/you-wouldnt-download-a-helmet/ | You Wouldn’t Download A Helmet? | Fenix Guthrie | [
"Transportation Hacks"
] | [
"airbag",
"airbags",
"bike hack",
"bike helmet"
] | Odds are, if you have ridden a bicycle for any amount of time, you have crashed. Crashes are fast, violent and chaotic events that leave you confused, and very glad to have a helmet. But what if there was another way of protecting your head? [Seth] decided to find out by taking a look at
the Hövding airbag helmet
.
The Hövding sits around your neck and looks somewhat akin to a neck pillow. It uses accelerometers situated in the fore and aft of the device to detect what it thinks is a crash. If a crash is detected, it will release a charge of compressed helium to inflate an airbag that wraps around the user’s head protecting a larger amount of the head then a traditional helmet. It also inflates around the wearer’s neck providing neck bracing in the impact further improving safety. The inflation process is incredibly fast and violent, very much akin to a car’s airbag. [Seth] demonstrated this on the process on two occasions to great effect, and to his amazement. While the idea of relying on computers to protect your head may sound ridiculous, studies have shown that the Hövding is
safer than a regular helmet in certain situations.
Unfortunately the deployment process was irreversible making the product single use. Moreover, the Hövding would deploy in a crash regardless of if you hit your head or not. While Hövding offered a crash replacement at a discount, this would have created large amounts of e-waste.
The Hövding helmet next to various commuter helmets
However, the design is not perfect. During the product’s use there were 27 reports of the device not deploying — particularly when struck by a vehicle. More reports exist of the device deploying erroneously when it detected, for example, bending over too quickly as a crash. It could not meet the US safety standards for helmets and therefore it was never allowed to be sold in the US.
Hövding argued that it was a helmet equivalent and should be exempt from those standards to no avail. Studies suggested that it
was not able to properly protect against sharp corner impacts
similar to the anvil tests used by the United States as the airbag would bottom out in such circumstances.
Ultimate Hövding’s failure as a business came down to software. As the project continued, scope broadened and the device’s firmware grew more complicated. New features were introduced including USB-C charging, OTA updates and phone crash notifications. However, this also appears to have resulted in a firmware bug that caused some units to not deploy, and were potentially sold this way with Hövding’s knowledge. This led the Swedish Consumer Agency to temporarily ban the product along with a stop-use and recall on all Hövding 3s. While the ban was lifted by a judge, the damage was done, consumer trust in Hövding was gone and they filed for bankruptcy in 2023. Unfortunately, this left the existing customers of the Hövding high and dry, without a working app, update method, or crash replacement program.
Airbags are complex and amazing pieces of safety equipment, and while this is the first bike airbag recall we have covered,
it’s not the first airbag recall we have seen. | 33 | 15 | [
{
"comment_id": "8127504",
"author": "Oscar",
"timestamp": "2025-05-14T05:31:44",
"content": "Living in Stockholm when these were popular, it was clear that it was simply a class and style symbol. It was a way to distinguish yourself from the poor bikers, without actually driving a car.€300, single-... | 1,760,371,548.749923 | ||
https://hackaday.com/2025/05/13/whats-an-lcr-databridge/ | What’s An LCR Databridge? | Al Williams | [
"Teardown"
] | [
"aim",
"LCR meter",
"Racal-Dana",
"z80"
] | [Thomas Scherrer] has an odd piece of vintage test equipment in his most recent video. An
AIM LCR Databridge 401
. What’s a databridge? We assume it was a play on words of an LCR bridge with a digital output. Maybe. You can see a teardown in the video below.
Inside the box is a vintage 1983 Z80 CPU with all the extra pieces. The device autoranges, at least it seems as much. However, the unit locks up when you use the Bias button, but it isn’t clear if that’s a fault or if it is just waiting for something to happen.
The teardown starts at about six minutes in. Inside is a very large PCB. The board is soldermasked and looks good, but the traces are clearly set by a not-so-steady hand. In addition to AIM, Racal Dana sold this device as a model 9341. The
service manual
for that unit is floating around, although we weren’t able to download it due to a server issue. A search could probably turn up copies.
From the service manual, it looks like the CPU doesn’t do much of the actual measurement work. There are plenty of other chips and a fast crystal that work together and feed an analog-to-digital converter.
LCR meters used to be somewhat exotic, but are
now fairly common
. It used to be common to measure reactance using
a grid dip meter
. | 6 | 4 | [
{
"comment_id": "8127471",
"author": "asheets",
"timestamp": "2025-05-14T03:00:32",
"content": "I had to look up what “LCR” stood for. I probably could have eventually guessed, but the context of the article was, for me, a bit off.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,371,548.582913 | ||
https://hackaday.com/2025/05/13/a-web-based-controller-for-your-garage-door/ | A Web Based Controller For Your Garage Door | Lewin Day | [
"Misc Hacks"
] | [
"ESP32",
"garage door",
"garage door opener",
"magnetic switch"
] | Garage doors! You could get out of your vehicle and open and close them yourself, but that kinda sucks. It’s much preferable to have them raise and lower courtesy some mechanical contrivance, and even better if that is controlled via the web.
[Juan Schiavoni] shows us how to achieve the latter with their latest project.
The web-based controller is based around a Xiao ESP32 microcontroller board, chosen for its baked-in WiFi connectivity. It’s set up to host its own web interface which you can login to with a password via a browser. If you have the correct authorization, you can then hit a button to open or close the garage door.
To interface the ESP32 with the garage door itself, [Juan] went the easy route. To trigger opening or closing the door, the ESP32 merely flicks an IO pin to toggle a transistor, which is hooked up to the button of the original garage door opener. Meanwhile, the ESP32 is also hooked up with a magnetic switch which is activated by a magnet on the garage door itself. This serves as a crude indicator as to the current status of the door—whether currently open or closed. This is crucial to ensure the indicated door status shown in the web app remains synced with the status of the door in reality.
It’s a simple project, and reminds us that we needn’t always do things the hard way. [Juan] could have figured out how to hook the ESP32 up with some radio chips to emulate the original garage door opener, but why bother? hooking it up to the original remote was far easier and more reliable anyway. We’ve seen
a good few garage door hacks over the years
; if you’ve got your own unique take on this classic, don’t hesitate to notify the
tipsline!
[Thanks to Stillman for the tip!] | 17 | 8 | [
{
"comment_id": "8127412",
"author": "Chris Cecil",
"timestamp": "2025-05-13T23:28:24",
"content": "Good work.I was planning something very similar at one point except I was just going to use a small relay across the pushbutton switch on the wall instead of opening a remote, or emulating the radio.J... | 1,760,371,548.846855 | ||
https://hackaday.com/2025/05/13/thermal-monocular-brings-the-heat-at-10x/ | Thermal Monocular Brings The Heat At 10X | Al Williams | [
"digital cameras hacks"
] | [
"ir camera",
"telescope"
] | [Project 326] is following up on his thermal microscope with a thermal telescope or, more precisely, a
thermal monocular
. In fact, many of the components and lenses in this project are the same as those in the microscope, so you could cannibalize that project for this one, if you wanted.
During the microscope project, [Project 326] noted that first-surface mirrors reflect IR as well as visible light. The plan was to make a Newtonian telescope for IR instead of light. While the resulting telescope worked with visible light, the diffraction limit prevented it from working for its intended purpose.
Shifting to a Keplerian telescope design was more productive. One of the microscope lenses got a new purpose, and he sourced new objective lenses that were relatively inexpensive.
The lens sets allow for 5X and 10X magnification. The lenses do reduce the sensitivity, but the telescope did work quite well. If you consider that the lenses are made to focus cutting lasers and not meant for use in imaging devices, it seems like an excellent result.
Missed the
thermal microscope
? Better catch up! Do you need a thermal camera?
Ask a duck
. | 5 | 3 | [
{
"comment_id": "8127341",
"author": "Beowulf Shaeffer",
"timestamp": "2025-05-13T20:12:27",
"content": "Huh… Really thought the mirrors would work.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8127420",
"author": "Lightislight",
"timestamp... | 1,760,371,548.796953 | ||
https://hackaday.com/2025/05/13/a-toolchanging-delta-3d-printer/ | A Toolchanging Delta 3D Printer | Aaron Beckendorf | [
"3d Printer hacks"
] | [
"delta 3D printer",
"delta printer",
"toolchanger",
"toolchanging"
] | We’ve seen quite a few delta 3D printers, and a good number of toolchanging printers, but not many that combine both worlds. Fortunately,
[Ben Wolpert]’s project fills that gap
with a particularly elegant and precise delta toolchanger.
The hotend uses three steel spheres and triangular brackets to make a repeatable three-point contact with the toolhead frame, and three pairs of corresponding magnets hold it in place. The magnets aren’t in contact, and the three magnets on the toolhead are mounted in a rotating ring. A motorized pulley on the printer’s frame drives a cable which runs through a flexible guide and around the rotating ring.
The whole setup is very reminiscent of the
Jubilee toolchanging system
, except that in this case, the pulley rotates the ring of magnets rather than a mechanical lock. By rotating the ring of magnets about 60 degrees, the system can move the pairs of magnets far enough apart to remove the hotend without much force.
The rest of the toolchanging system is fairly straightforward: each tool’s parking area consists of two metal posts which slot through corresponding holes in the hotend’s frame, and the motherboard uses some RepRapFirmware macros to coordinate the tool changes. The only downside is that a cooling fan for the hotend still hadn’t been implemented, but a desk fan seemed to work well enough in [Ben]’s tests. The files for the necessary hardware and software customizations are all available
on GitHub
.
We’ve only seen a similar toolchanging system for a delta printer
once before
, but we have seen a
great variety
of
toolchangers
on the more common Cartesian systems. Don’t like the idea of changing extruders? We’ve also seen a
multi-extruder printer
that completely eliminates tool switching. | 3 | 3 | [
{
"comment_id": "8127413",
"author": "Andy",
"timestamp": "2025-05-13T23:29:09",
"content": "DeltaMaker has had this for a while. Pretty much same concept.https://www.deltamaker.com/blogs/news/halo-toolchanger-percision-test",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"co... | 1,760,371,549.209402 | ||
https://hackaday.com/2025/05/13/remembering-memory-ems-and-tsrs/ | Remembering Memory: EMS, And TSRs | Al Williams | [
"Hackaday Columns",
"Retrocomputing",
"Slider"
] | [
"8086",
"8088",
"ems",
"IBM PC",
"TSR"
] | You often hear that Bill Gates once proclaimed, “640 kB is enough for anyone,” but, apparently, that’s a myth — he never said it. On the other hand, early PCs did have that limit, and, at first, that limit was mostly theoretical.
After all, earlier computers often topped out at 64 kB or less, or — if you had some fancy bank switching — maybe 128 kB. It was hard to justify the cost, though. Before long, though, 640 kB became a limit, and the industry found workarounds. Mercifully, the need for these eventually evaporated, but for a number of years, they were a part of configuring and using a PC.
Why 640 kB?
The original IBM PC sported an Intel 8088 processor. This was essentially an 8086 16-bit processor with an 8-bit external data bus. This allowed for cheaper computers, but both chips had a strange memory addressing scheme and could access up to 1 MB of memory.
In fact, the 8088 instructions could only address 64 kB, very much like the old 8080 and Z80 computers. What made things different is that they included a number of 16-bit segment registers. This was almost like bank switching. The 1 MB space could be used 64 kB at a time on 16-byte boundaries.
So a full address was a 16-bit segment and a 16-bit offset. Segment 0x600D, offset 0xF00D would be written as 600D:F00D. Because each segment started 16-bytes after the previous one, 0000:0020, 0001:0010, and 0002:0000 were all the same memory location. Confused? Yeah, you aren’t the only one.
What happened to the other 360 kB? Well, even if Gates didn’t say that 640 kB was enough, someone at IBM must have. The PC used addresses above 640 kB for things like the video adapter, the BIOS ROM, and even just empty areas for future hardware. MSDOS was set up with this in mind, too.
The 640K user area, 384K system area, and almost 64K of HMA in a PC (80286 or above)
For example, your video adapter used memory above 640 kB (exactly where depended on the video card type, which was a pain). A network card might have some ROM up there — the BIOS would scan the upper memory looking for ROMs on system boot up. So while the user couldn’t get at that memory, there was a lot going on there.
What Were People Doing?
Speaking of MSDOS, you can only run one program at a time in MSDOS, right? So what were people doing that required more than 640 kB? You weren’t playing video. Or high-quality audio.
There were a few specialized systems that could run multiple DOS programs in text-based windows, DesqView and TopView, to name two. But those were relatively rare. GEM was an early Windows-like GUI, too, but again, not that common on early PCs.
Sidekick activated
However, remember that MSDOS didn’t do a lot right out of the box. Suppose you had a new-fangled network card and a laser printer. (You must have been rich back then.) Those devices probably had little programs to load that would act like device drivers — there weren’t any in MSDOS by default.
The “driver” would be a regular program that would move part of itself to the top of memory, patch MSDOS to tell it the top of memory was now less than it was before, and exit. So a 40 kB network driver would eat up from 600 kB to 640 kB, and MSDOS would suddenly think it was on a machine with 600 kB of RAM instead of 640. If you had a few of these things, it quickly added up.
TSRs
Then came Sidekick and similar programs. The drivers were really a special case of a “terminate and stay resident” or TSR program. People figured out that you could load little utility programs the same way. You simply had to hook something like a timer interrupt or keyboard interrupt so that your program could run periodically or when the user hit some keys.
Sidekick might not have been the first example of this, but it was certainly the first one to become massively successful and helped put Borland on the map, the people who were mostly famous or would be famous for Turbo Pascal and Turbo C.
Of course, these programs were like interrupt handlers. They had to save everything, do their work, and then put everything back or else they’d crash the computer. Sidekick would watch for an odd key stroke, like Ctrl+Alt or both shift keys, and then pop up a menu offering a calculator, a notepad, a calendar, an ASCII table, and a phone dialer for your modem.
Sidekick caught on and spawned many similar programs. You might want a half dozen or more resident programs in your daily MSDOS session. But if you loaded up a few TSRs and a few drivers, you were quickly running out of memory. Something had to be done!
EMS
EMS board were “expanded memory.” There actually were a few flavors, not all of which caught on. However, a standard developed by Intel, Microsoft, and Lotus did become popular.
The Captain286 EMS board used SIMMs, unlike most of its contemporaries
In a nutshell, EMS reserved — at least at first — a 64 kB block of memory above the 640 kB line and then contained a lot of memory that you could switch in and out of that 64 kB block. In fact, you generally switched 16 kB at a time, so you could access four different EMS 16 kB pages at any one time.
This was complex and slow. The boards usually had some way to move the block address, so you had to take that into account. Later boards would offer even more than 64 kB available in upper memory or even allow for dynamic mapping. Some later boards even had sets of banking registers so you could context switch if your software was smart enough to do so.
EMS was important because even an 8088-based PC could use it with the right board. But, of course, newer computers like the IBM AT used 80286 processors and, later, even newer processors were common. While they could use EMS, they also had more capabilities.
Next Time
If you had a newer computer with an 80286 or better, you could directly access more memory. Did you notice the high memory area (HMA) in the memory map? That’s only for newer computers. But, either way, it was not fully supported by MSDOS.
Many boards for the newer computers could provide both EMS and just regular memory. The real issue was how could you use the “regular memory” above the 1MB line? I’ll tell you more about that next time, including a trick independently discovered by a number of hackers at about the same time. | 48 | 19 | [
{
"comment_id": "8127254",
"author": "Jon Mayo",
"timestamp": "2025-05-13T17:18:18",
"content": "I had a 386 with options in the BIOS to assign some of the memory to hardware EMS. Probably a C&T NEAT (CS8281?) but I don’t remember.I had 6 of those 386sx33 motherboards with 4MB – 16MB of RAM in each... | 1,760,371,548.991313 | ||
https://hackaday.com/2025/05/13/the-worlds-longest-range-led-flashlight/ | The World’s Longest Range LED Flashlight | John Elliot V | [
"LED Hacks"
] | [
"led flashlight",
"long range"
] | [ApprehensiveHawk6178] reports that they have made
the world’s longest range LED flashlight
! While technically “handheld”, you’re gonna need both hands for this monster. According to the creator, it draws 1.2 kW (20 A @ 60 V) to deliver 100,000 lumens and approximately 20,000,000 candelas.
This spotlight is made from 48 white LEDs, wired in 16S3P configuration, and is powered by a similarly beefy 20S2P battery pack. That 1.2 kW power draw generates a lot of heat which is dissipated with an array of heat sinks and five cooling fans. Total cost was in the order of $2,000 USD.
It can be controlled via Bluetooth, and can run from its batteries for 30 minutes at full power. If you’d like to geek out over the specs click-through and read the discussion, a lot of technical detail is given and there are a bunch of photos showing the internals and assembly.
We’ve seen
high-output LED lights with water cooling in the past
, and wonder if that might be the next step for this particular build.
Thanks to [kms] for the tip. | 39 | 17 | [
{
"comment_id": "8127198",
"author": "threeve",
"timestamp": "2025-05-13T15:32:40",
"content": "https://xkcd.com/1603/",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8127205",
"author": "macsimki",
"timestamp": "2025-05-13T15:46:21",
... | 1,760,371,549.122538 | ||
https://hackaday.com/2025/05/11/reading-the-color-of-money/ | Reading The Color Of Money | Matt Varian | [
"Reverse Engineering"
] | [
"money",
"reverse engineering"
] | Ever wondered what happens when you insert a bill into a vending machine? [Janne] is back with his latest project: reverse engineering a
banknote validator
. Curious about how these common devices work, he searched for information but found few resources explaining their operation.
To learn more, [Janne] explored the security features that protect banknotes from counterfeiting. These can include microprinting, UV and IR inks, holograms, color-shifting coatings, watermarks, magnetic stripes, and specialty paper. These features not only deter fraud but also enable validators to quickly verify a bill’s authenticity.
[Janne] purchased several banknote validators to disassemble and compare. Despite varied exteriors, their core mechanisms were similar: systems to move the bill smoothly, a tape head to detect magnetic ink or security strips, and optical sensors to inspect visible, UV, and IR features. By reverse engineering the firmware of two devices, he uncovered their inner workings. There is a calibration procedure they use to normalize their readings, then it will analyze a bill through a sophisticated signal processing pipeline. If the data falls within a narrow acceptance range, the device authenticates the bill; otherwise, it rejects it.
Head over to his site to check out all the details he discovered while exploring these devices, as well as exploring the other cool projects he’s worked on in the past. Reverse engineering offers a unique window into technology Check out
other projects
we’ve featured showcasing this skill. | 9 | 3 | [
{
"comment_id": "8126722",
"author": "Ostracus",
"timestamp": "2025-05-12T02:36:07",
"content": "Seeing how Passports are made is also interesting.https://youtu.be/bnKyw5-_E6o",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126807",
"author": "R",
... | 1,760,371,549.045612 | ||
https://hackaday.com/2025/05/11/hackaday-links-may-11-2025/ | Hackaday Links: May 11, 2025 | Dan Maloney | [
"Hackaday Columns",
"Hackaday links",
"Slider"
] | [
"ai",
"arctic",
"court",
"deep-fake",
"galaxies",
"hackaday links",
"Hubble",
"Indian Ocean",
"jwst",
"Kosmos 482",
"legal",
"Meltdown",
"nuclear",
"pressurized water reactor",
"PWR",
"thermal paste",
"venus",
"victim"
] | Did artificial intelligence just
jump the shark
? Maybe so, and it came from the legal world of all places, with
this report
of an AI-generated victim impact statement. In an apparent first, the family of an Arizona man killed in a road rage incident in 2021 used AI to bring the victim back to life to testify during the sentencing phase of his killer’s trial. The video was created by the sister and brother-in-law of the 37-year-old victim using old photos and videos, and was quite well done, despite the normal uncanny valley stuff around lip-syncing that seems to be the fatal flaw for every deep-fake video we’ve seen so far. The victim’s beard is also strangely immobile, which we found off-putting.
In the video, the victim expresses forgiveness toward his killer and addresses his family members directly, talking about things like what he would have looked like if he’d gotten the chance to grow old. That seemed incredibly inflammatory to us, but according to Arizona law, victims and their families get to say pretty much whatever they want in their impact statements. While this appears to be legal, we wouldn’t be surprised to see it appealed, since the judge tacked an extra year onto the killer’s sentence over what the prosecution sought based on the power of the AI statement. If this tactic withstands the legal tests it’ll no doubt face, we could see an entire industry built around this concept.
Last week
, we warned about the impending return of Kosmos 482, a Soviet probe that was supposed to go to Venus when it was launched in 1972. It never quite chooched, though, and ended up circling the Earth for the last 53 years.
The satellite made its final orbit on Saturday morning
, ending up in the drink in the Indian Ocean, far from land. Alas, the faint hope that it would have a soft landing thanks to the probe’s parachute having apparently been deployed at some point in the last five decades didn’t come to pass. That’s a bit of a disappointment to space fans, who’d love to get a peek inside this priceless bit of space memorabilia. Roscosmos says they monitored the descent, so presumably they know more or less where the debris rests. Whether it’s worth an expedition to retrieve it remains to be seen.
Are we really at the point where we have to worry about counterfeit thermal paste?
Apparently, yes
, judging by the effort Arctic Cooling is putting into authenticity verification of its MX brand pastes. To make sure you’re getting the real deal, boxes will come with seals that rival those found on over-the-counter medications and scratch-off QR codes that can be scanned and cross-referenced to an online authentication site. We suppose it makes sense; chip counterfeiting is a very real thing, after all, and it’s probably as easy to put a random glob of goo into a syringe as it is to laser new markings onto a chip package. And Arctic compound commands a pretty penny, so the incentive is obvious. But still, something about this just bothers us.
Another very cool astrophotography shot this week, this time
a breathtaking collection of galaxies
. Taken from the Near Infrared camera on the James Webb Space Telescope with help from the Hubble Space Telescope and the XMM-Newton X-ray space observatory, the image shows thousands of galaxies of all shapes and sizes, along with the background X-ray glow emitted by all the clouds of superheated dust and gas between them. The stars with the characteristic six-pointed diffraction spikes are all located within our galaxy, but everything else is a galaxy. The variety is fascinating, and the scale of the image is mind-boggling. It’s galactic eye candy!
And finally, if you’ve ever wondered about what happens when a nuclear reactor melts down, you’re in luck with
this interesting animagraphic
on the process. It’s not a detailed 3D render of any particular nuclear power plant and doesn’t have a specific meltdown event in mind, although it does mention both Chernobyl and Fukushima. Rather, it’s a general look at pressurized water reactors and what can go wrong when the cooling water stops flowing. It also touches on potentially safer designs with passive safety systems that rely on natural convection to keep cooling water circulating in the event of disaster, along with gravity-fed deluge systems to cool the containment vessel if things get out of hand. It’s a good overview of how reactors work and where they can go wrong. Enjoy. | 6 | 3 | [
{
"comment_id": "8126718",
"author": "localroger",
"timestamp": "2025-05-12T02:21:06",
"content": "It is important to note that the AI victim statement doesn’t reflect anything that the victim might have said or believed, since the victim wasn’t there to participate in its creation. Rather, it’s re... | 1,760,371,549.167648 | ||
https://hackaday.com/2025/05/11/open-source-elint-accidentally-from-nasa/ | Open Source ELINT Accidentally From NASA | Al Williams | [
"Space"
] | [
"ELINT",
"jamming",
"SMAP"
] | You normally think of ELINT — Electronic Intelligence — as something done in secret by shadowy three-letter agencies or the military. The term usually means gathering intelligence from signals that don’t contain speech (since that’s COMINT). But [Nukes] was looking at public data from NASA’s SMAP satellite and made an interesting discovery. Despite the satellite’s mission to measure soil moisture, it also
provided data on strange happenings in the radio spectrum
.
While 1.4 GHz is technically in the L-band, it is reserved (from 1.400–1.427 GHz) for specialized purposes. The frequency is critical for radio astronomy, so it is typically clear other than low-power safety critical data systems that benefit from the low potential for interference. SMAP, coincidentally, listens on 1.41 GHz and maps where there is interference.
Since there aren’t supposed to be any high-power transmitters at that frequency, you can imagine that anything showing up there is probably something unusual and interesting. In particular, it is often a signature for military jamming since nearby frequencies are often used for passive radar and to control drones. So looking at the data can give you a window on geopolitics at any given moment.
The data is out there, and a
simple Python script
can pull it. We imagine this is the kind of data that only a spook in a SCIF would have had just a decade or two ago.
Jamming tech is
secretive but powerful
. SMAP isn’t the only satellite to have its mission
unexpectedly repurposed
. | 9 | 2 | [
{
"comment_id": "8126713",
"author": "limroh",
"timestamp": "2025-05-12T02:02:11",
"content": "Interesting but the source is – let’s say – a little “odd”.a handful of posts since Jan 2024an empty about page:https://radioandnukes.substack.com/aboutlittle wired distinction/separation between Crimea an... | 1,760,371,549.292957 | ||
https://hackaday.com/2025/05/11/learn-15-print-in-place-mechanisms-in-15-minutes/ | Learn 15 Print-in-Place Mechanisms In 15 Minutes | Dave Rowntree | [
"3d Printer hacks"
] | [
"3d printed",
"design",
"flexures",
"living hinge",
"Mechanisms",
"springs"
] | 3D printed in-place mechanisms and flexures, such as living hinges, are really neat when you can get them to print correctly. But how do you actually do that? YouTuber [Slant 3D] is here with a
helpful video demonstrating the different kinds of springs and hinges
(Video, embedded below) that can be printed reliably, and discusses some common pitfalls and areas to concentrate upon.
Living hinges are everywhere and have been used at least as long as humans have been around. The principle is simple enough; join two sections to move with a thinned section of material that, in small sections, is flexible enough to distort a few times without breaking off. The key section is “a few times”, as all materials will eventually fail due to overworking. However, if this thing is just a cheap plastic case around a low-cost product, that may not be a huge concern. The video shows a few ways to extend flexibility, such as spreading the bending load across multiple flexure elements to reduce the wear of individual parts, but that comes at the cost of compactness.
Moving on from springs, the second part of the video describes a few strategies for print-in-place hinges, describing how they fail, and what to do to mitigate. Again, robustness comes at a cost, in this case, increased bulk, but with 3D printing, you get what you pay for. Overall, it’s a nice, concise guide to the topic and well worth a mere seventeen minutes of your time, we reckon.
We see 3D printed flexure mechanisms a lot ’round here,
like this for example
. But
how precise are they
? Finally, we think this
3D printed spherical flexure joystick
is cool, but must have been a bit tricky to model!
Thanks to [Hari Wiguna] for the tip! | 4 | 4 | [
{
"comment_id": "8126745",
"author": "Deividas Strole",
"timestamp": "2025-05-12T05:20:28",
"content": "3D printing flexures and living hinges is such a cool challenge! Slant 3D’s video does a great job breaking down the process and pointing out common pitfalls. It’s amazing how small adjustments ca... | 1,760,371,549.250588 | ||
https://hackaday.com/2025/05/11/exploring-the-rp2350s-uart-bootloader/ | Exploring The RP2350’s UART-Bootloader | Tyler August | [
"Microcontrollers"
] | [
"microcontroller",
"rp2350",
"uart",
"UART bootloader"
] | The RP2350 has a few advantages over its predecessor, one of which is the ability to load firmware remotely via UART, as [Thomas Pfister]
has documented on his blog
and in the video below.
[Thomas] had a project that needed more PWM than the RP2350 could provide, and hit upon the idea of using a second RP2350 as a port expander. Now, one could hard-code this, but dealing with two sets of firmware on one board can be annoying. That’s where the UART bootloader comes in: it will allow [Thomas] to program the port-expander RP2350 using the main microcontroller. Thus he only has to worry about one firmware, speeding up development.
There are limits to this technique: for one, your code must fit into the RP2350’s RAM– but the chip has 512 kB. While 640 kB should be enough for anyone, 512 kB is plenty for the port-expander [Thomas] is working on. The second drawback is that your device now has a boot time of a second or so, since the UART connection is not exactly high-bandwidth. Third, using UART on the same pins as the bootloader within the program is a bit tricky, though [Thomas] found a solution that may soon be in the SDK.
[Thomas] also wanted to be able to perform this trick remotely, which isn’t exactly UART’s forte. RS-485 comes to the rescue, via TI’s THVD1450. That worked reliably at the 10m cable length used for the test. [Thomas] sees no reason it could not work over much longer distances. ([Thomas] suggests up to 100 m, but the baud rate is fairly low, so we wouldn’t be surprised if you could push it quite a bit further than that. The standard is good out to a kilometer, after all.) For all the wrinkles and links to tips and solutions, plus of course [Thomas]’s code, check out the blog. If you want to listen to the information, you can check out the video below.
We’re grateful to [Thomas] for letting us know about his
project via the tip line,
like we are to everyone who
drops us a tip
. Hint, hint.
Given that it is the new chip on the block, we haven’t seen too many hacks with the RP2350 yet, but
they’re starting to trickle in
. While a UART bootloader is a nice feature to have,
it can also introduce a security risk
, which is always something to keep in mind. | 12 | 6 | [
{
"comment_id": "8126616",
"author": "CRJEEA",
"timestamp": "2025-05-11T15:50:22",
"content": "It might be interesting for a cubesat.",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8126623",
"author": "0xdeadbeef",
"timestamp": "2025-05-11T16:19:10",
... | 1,760,371,549.527578 | ||
https://hackaday.com/2025/05/11/tearing-down-a-forgotten-video-game/ | Tearing Down A Forgotten Video Game | Al Williams | [
"Retrocomputing",
"Teardown"
] | [
"pong",
"video game"
] | Remember Video Volley? No? We don’t either. It looks like it was a very
early video game console
that could play tennis, hockey, or handball. In this video, [James] tears one apart. If you are like us, we are guessing there will be little more than one of those General Instrument video game chips inside.
These don’t look like they were mass-produced. The case looks like something off the shelf from those days. The whole thing looks more like a nice homebrew project or a pretty good prototype. Not like something you’d buy in a store.
Even inside, the wiring looks decidedly hand-built. The cheap phenolic PCB contained a surprise. The box does have a dedicated “pong” chip. But it isn’t from General Instruments! It’s a National Semiconductor chip instead.
The controllers are little more than sliding potentiometers in a box with a switch. We wonder how many of these were made and what they sold for new. If you know anything, let us know in the comments.
We still see the occasional project around a
General Instruments chip
. If you really want a challenge for a homebrew pong,
ditch the pong chip
and all the other ICs, too. If you want to read more about the history of the pong chip, you’ll probably enjoy this
blog post
from [pong-story]. | 5 | 4 | [
{
"comment_id": "8126560",
"author": "Chris Pepin",
"timestamp": "2025-05-11T11:20:56",
"content": "Pong machines are the 70’s equivalent of the all-in-one TV game joysticks of the 2000’s.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126652",
"aut... | 1,760,371,549.478961 | ||
https://hackaday.com/2025/05/11/boxie-a-gameboy-esque-audio-player/ | Boxie – A Gameboy-Esque Audio Player | Matt Varian | [
"Musical Hacks"
] | [
"audio player",
"cartidge",
"ESP32-S3",
"nimh"
] | This little audiobook player is a stellar example of the learning process behind a multifaceted project blending mechanical, electrical, and software design. [Mario] designed this
audiobook player
, dubbed Boxie, for his 3-year-old son to replace the often-used but flawed Toniebox.
The inspiration for Boxie was the Toniebox, a kid-friendly audiobook player. While functional, the Toniebox had drawbacks: it required internet connectivity, limited media selection, and had unreliable controls. Enter Boxie, a custom-built, standalone audiobook player free from web services, designed to address these issues with superior audio quality and toddler-friendly controls.
Boxie’s media is stored on microSD cards inserted into a slot on the device. To make this manageable for a toddler, he designed a PCB with a standard microSD card interface, ensuring easy swapping of audiobooks. The enclosure, crafted via 3D printing, is durable and compact, tailored for small hands.
The cartridges slide into the body of the Boxie. This presented a problem, most cartridge media utilize edge connectors. Strictly speaking, his DIY cartridges didn’t have those and couldn’t use traditional cartridge reader components. First trying pogo pins, he ran into several issues, most notably the inability to hold up to the wear and tear of a 3-year-old. A clever hack to add robustness was achieved when he switched to using a series of battery springs to interface with the cartridge.
Inside the Boxie lives an ESP32-S3 microcontroller, which provides the smarts to read all the controls, play audio from the inserted cartridge. The main housing also contains the battery, DAC, amp, and speaker. Mario faced a fair number of new challenges on this project, including designing a battery charging circuit and building his own ESP32-S3 board with support for charging NiMH batteries.
All of the 3D designs, PCB files, and source code are
available on his GitHub account
. If you’re interested in making a Boxie for a young one in your life, be sure to go check out his detailed write-up. If you enjoyed this project, be sure to check out the other DIY
audio players
we’ve featured. | 8 | 6 | [
{
"comment_id": "8126513",
"author": "jme",
"timestamp": "2025-05-11T08:35:33",
"content": "This is a fantastic project!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8126528",
"author": "Atoomnet",
"timestamp": "2025-05-11T09:02:38",
"content": "... | 1,760,371,549.581486 | ||
https://hackaday.com/2025/05/10/another-old-thinkpad-gets-a-new-motherboard/ | Another Old ThinkPad Gets A New Motherboard | Jenny List | [
"Retrocomputing"
] | [
"IBM Thinkpad",
"motherboard",
"x200"
] | The Thinkpad line of laptops, originally from IBM, and then from Lenovo, have long been the choice of many in our community. They offer a level of robustness and reliability missing in many cheaper machines. You may not be surprised to find that this article is being written on one. With such a following, it’s not surprising that a significant effort has gone into upgrading older models. For example, we have [Franck Deng]’s
new motherboard for the Thinkpad X200 and X201
. These models from the end of the 2000s shipped as far as we can remember with Core 2 Duo processors, so we can imagine they would be starting to feel their age.
It’s fair to say the new board isn’t a cheap option, but it does come with a new Core Ultra 7 CPU, DDR5 memory, M.2 interfaces for SSDs alongside the original 2.5″ device, and USB-C with Thunderbolt support. There are a range of screen upgrade options. For an even more hefty price, you can buy a completely rebuilt laptop featuring the new board. We’re impressed with the work, but we have to wonder how it would stack up against a newer Thinkpad for the price.
If you’re curious to see more of the same,
this isn’t the first such upgrade we’ve seen
.
Thanks [Max] for the tip. | 18 | 10 | [
{
"comment_id": "8126531",
"author": "Geoffrey Dowen",
"timestamp": "2025-05-11T09:18:35",
"content": "I just purchased @ T14 gen 1",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126559",
"author": "The Solutor",
"timestamp": "2025-05-11T11:... | 1,760,371,549.639077 | ||
https://hackaday.com/2025/05/10/an-llm-for-the-raspberry-pi/ | An LLM For The Raspberry Pi | Al Williams | [
"Artificial Intelligence",
"Raspberry Pi"
] | [
"LLM",
"microsoft"
] | Microsoft’s latest Phi4 LLM has 14 billion parameters that require about 11 GB of storage. Can you run it on a Raspberry Pi? Get serious. However, the
Phi4-mini-reasoning model
is a cut-down version with “only” 3.8 billion parameters that requires 3.2 GB. That’s more realistic and, in a recent video, [Gary Explains] tells you how to add this LLM to your Raspberry Pi arsenal.
The version [Gary] uses has four-bit quantization and, as you might expect, the performance isn’t going to be stellar. If you are versed in all the LLM lingo, the quantization is the way weights are stored, and, in general, the more parameters a model uses, the more things it can figure out.
As a benchmark, [Gary] likes to use what he calls “the Alice question.” In other words, he asks for an answer to this question: “Alice has five brothers and she also has three sisters. How many sisters does Alice’s brother have?” While it probably took you a second to think about it, you almost certainly came up with the correct answer. With this model, a Raspberry Pi can answer it, too.
The first run seems fairly speedy, but it is running on a PC with a GPU. He notes that the same question takes about 10 minutes to pop up on a Raspberry Pi 5 with 4 cores and 8GB of RAM.
We aren’t sure what you’d do with a very slow LLM, but it does work. Let us know what you’d use it for, if anything, in the comments.
There are some
other small models if you don’t like Phi4
. | 32 | 15 | [
{
"comment_id": "8126456",
"author": "Experienced Experimenter",
"timestamp": "2025-05-11T02:38:47",
"content": "There are more choices available for limited memory systems. Qwen3 8B is remarkably competitive to that 14B and to the 70Bs for its size.",
"parent_id": null,
"depth": 1,
"rep... | 1,760,371,551.921845 | ||
https://hackaday.com/2025/05/10/restoring-a-sinclair-c5-for-the-road/ | Restoring A Sinclair C5 For The Road | Jenny List | [
"Transportation Hacks"
] | [
"5d",
"Clive Sinclair",
"Sinclair C5"
] | The Sinclair C5 was Sir Clive’s famous first venture into electric mobility, a recumbent electric-assisted tricycle which would have been hardly unusual in 2025. In 1985, though, the C5 was so far out there that it became a notorious failure. The C5 retains a huge following among enthusiasts, though, and among those is [JSON Alexander,
who has bought one and restored it
.
We’re treated to a teardown and frank examination of the vehicle’s strengths and weaknesses, during which we see the Sinclair brand unusually on a set of tyres, and the original motor, which is surprisingly more efficient than expected. Sir Clive may be gone, but this C5 will live again.
We’ve had the chance to road test a C5 in the past, and it’s fair to say that we can understand why such a low-down riding position was not a success back in the day. It’s unusual to see one in as original a condition as this one, it’s more usual to see
a C5 that’s had a few upgrades
. | 26 | 7 | [
{
"comment_id": "8126421",
"author": "Hirudinea",
"timestamp": "2025-05-10T23:36:44",
"content": "Restoring it, good idea. Putting it on the road, not so much.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126534",
"author": "Jan-Willem Markus",
... | 1,760,371,551.783809 | ||
https://hackaday.com/2025/05/10/move-over-lithopane-3d-printed-3d-photos-with-gaussian-splats/ | Move Over, Lithophane: 3D Printed 3D Photos With Gaussian Splats | Tyler August | [
"3d Printer hacks"
] | [
"3d print",
"DLP printer",
"gaussian splat",
"resin"
] | If you had asked us yesterday “How do you 3D Print a Photo”, we would have said “well, that’s easy, do a lithophane”– but artist, hacker and man with a very relaxing voice [Wyatt Roy] has a much more impressive answer:
Gaussian splats, rendered in resin.
Gaussian splats are a 3D scanning technique aimed at replicating a visual rather than geometry, like the mesh-based 3D-scanning we usually see on Hackaday. Using photogrammetry, a point cloud is generated with an associated 3D Gaussian function describing the colour at that point. Blend these together, and you can get some very impressive photorealistic 3D environments. Of course, printing a Gaussian smear of colour isn’t trivial, which is where the hacking comes in.
14-face isospheres do a good job of replicating the complicated Gaussian, as seen with this experimental long-exposure shot.
[Wyatt] first generates the Gaussian splats with an app called Polycam, which outputs inscrutable binary .ply files. With AI assistance of dubious quality, [Wyatt] first created a python script to decompile this data into an ASCII file, which is then fed into a Rhino script to create geometry for printing. Rather than try and replicate the Gaussian splat at each point perfectly, which would melt his PC, [Wyatt] uses 14-face isospheres to approximate the 3D Gaussian functions. These then get further postprocessing to create a printable mesh.
Printing this isn’t going to be easy for most of us, because [Wyatt] is using a multi-color DLP resin printer. The main body is clear resin, and black or white resin used for the space defined by the isospheres created from the Gaussian Splat. When the interior color is white, the effect is quite similar to those acrylic cubes you sometimes see, where a laser has etched bubbles into their depths, which makes us wonder if that might be a more accessible way to use this technique.
We talked about
Gaussian splats when the technique was first announced
, but it’s obvious the technology has come a long way since then. We did feature a
hack with multicolor resin prints last year,
but it was much more manual than the fancy machine [Wyatt] uses here. Thanks to [Hari Wiguna] for the tip. | 24 | 7 | [
{
"comment_id": "8126403",
"author": "Daniel",
"timestamp": "2025-05-10T20:51:37",
"content": "And he didn’t notice that his idea of Gaussian splats is wrong? They are not the Gaussian distribution curve rotated around the x axis, which looks like an onion. He has to take that function, give it the ... | 1,760,371,551.851985 | ||
https://hackaday.com/2025/05/10/best-practices-for-fdm-printing/ | Best Practices For FDM Printing | Al Williams | [
"3d Printer hacks"
] | [
"3D design",
"3d printing"
] | If you’ve been designing parts for 3D printing, you probably have some tricks and standards for your designs. [Rahix] decided to write out
a well-thought-out set of design rules for FDM prints
, and we can all benefit.
One of the things we liked about the list is that it’s written in a way that explains everything. Every so often, there’s a box with a summarized rule for that topic. At the end, there’s a list of all the rules. The rules are also in categories, including part strength, tolerance, optimization, integration, machine elements, appearance, and vase mode.
For example, section two deals with tolerance and finish. So, rule R2.8 says, “Do not use circular holes for interference fits. Use hexagon or square holes instead.”
We also appreciate that [Rahix] touched on some of the counter-intuitive aspects of designing for FDM printing. For example, you might think adding voids in your part will reduce the filament and time required to print it, but in many cases it can have the opposite effect.
Some of these — maybe even most of these — won’t surprise you, but you still might take away a tidbit or two. But having it all down in a checklist and then the ability to scroll up and find the rationale for the rule is great.
Do you have any rules you’d add? Or change? Let us know. Meanwhile, we were eyeing our favorites about adding
machine elements to prints
. | 38 | 10 | [
{
"comment_id": "8126372",
"author": "Echo",
"timestamp": "2025-05-10T18:26:49",
"content": "Did not expect to learn much new, but I ended up liking its style and attentionto details.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8127018",
"author":... | 1,760,371,551.666984 | ||
https://hackaday.com/2025/05/10/man-and-machine-vs-man-vs-machine/ | “Man And Machine” Vs “Man Vs Machine” | Elliot Williams | [
"Hackaday Columns",
"Rants",
"Slider"
] | [
"art",
"artificial intelligence",
"laser cutter",
"machine",
"mastery"
] | Every time we end up talking about 3D printers, Al Williams starts off on how bad he is in a machine shop. I’m absolutely sure that he’s exaggerating, but the gist is that he’s much happier to work on stuff in CAD and let the machine take care of the precision and fine physical details. I’m like that too, but with me, it’s the artwork.
I can’t draw to save my life, but once I get it into digital form, I’m pretty good at manipulating images. And then I couldn’t copy that out into the real world, but that’s what the laser cutter is for, right? So the gameplan for this year’s Mother’s Day gift (reminder!) is three-way. I do the physical design, my son does the artwork, we combine them in FreeCAD and then hand it off to the machine. Everyone is playing to their strengths.
So why does it feel a little like cheating to just laser-cut out a present? I’m not honestly sure. My grandfather was a trained architectural draftsman before he let his artistic side run wild and went off to design jewellery. He could draw a nearly perfect circle with nothing more than a pencil, but he also used a
French curve set
, a
pantograph
, and a
rolling architect’s ruler
when they were called for. He had his tools too, and I bet he’d see the equivalence in mine.
People have used tools since the stone age, and the people who master their tools transcend them, and produce work where the “human” shines through despite having traced a curve or having passed the Gcode off to the cutter. If you doubt this, I’ll remind you of the technological feat that is the piano, with which people nonetheless produce music that doesn’t make you think of the hammers or of the tremendous cast metal frame. The tech disappears into the creation.
I’m sure there’s a parable here for our modern use of AI too, but I’ve got a Mother’s Day present to finish.
This article is part of the Hackaday.com newsletter, delivered every seven days for each of the last 200+ weeks. It also includes our favorite articles from the last seven days that you can see on
the web version of the newsletter
.
Want this type of article to hit your inbox every Friday morning?
You should sign up
! | 10 | 4 | [
{
"comment_id": "8126342",
"author": "Ostracus",
"timestamp": "2025-05-10T17:10:18",
"content": "“People have used tools since the stone age, and the people who master their tools transcend them, and produce work where the “human” shines through despite having traced a curve or having passed the Gco... | 1,760,371,551.439039 | ||
https://hackaday.com/2025/05/10/poe-powered-gpib-adapter-with-ethernet-and-usb-c-support/ | PoE-powered GPIB Adapter With Ethernet And USB-C Support | Maya Posch | [
"Peripherals Hacks",
"Retrocomputing"
] | [
"ethernet",
"gpib",
"power over ethernet",
"test equipment"
] | In the world of (expensive) lab test equipment the GPIB (general purpose interface bus) connection is hard to avoid if you want any kind of automation, but nobody likes wrangling with the bulky cables and compatibility issues when they can just use Ethernet instead. Here
[Chris]’s Ethernet-GPIB adapter
provides an easy solution, with both Power over Ethernet (PoE) and USB-C power options. Although commercial adapters already exist, these are rather pricey at ~$500.
Features
of this adapter include a BOM total of <$50, with power provided either via PoE (802.3af) or USB-C (5V-only). The MCU is an ATmega4809 with the Ethernet side using a Wiznet W5500 SPI Ethernet controller. There is also a serial interface (provided by a CH340X USB-UART adapter), with the firmware based on the
AR488 project
.
The adapter supports both the VXI-11.2 and Prologix protocols, though not at the same time (due to ROM size limitations). All design documents are available via the GitHub repository, with the author also selling assembled adapters and providing support
primarily via the EEVBlog forums
. | 10 | 6 | [
{
"comment_id": "8126310",
"author": "Oliver",
"timestamp": "2025-05-10T13:07:54",
"content": "Wow – this could not come more timely as I recently acquired a trusty old HP 53131A frequency counter in pristine condition (super bright VFD, clean, no smell, caps looking good so far). Looking around the... | 1,760,371,551.590486 | ||
https://hackaday.com/2025/05/10/web-dashboard-and-ota-updates-for-the-esp32/ | Web Dashboard And OTA Updates For The ESP32 | John Elliot V | [
"Microcontrollers",
"Software Development"
] | [
"admin dashboard",
"embedded web server",
"ESP32",
"gui",
"mongoose",
"OTA",
"over-the-air update",
"REST interface",
"web-based interface"
] | Today we are happy to present
a web-based GUI for making a web-based GUI
! If you’re a programmer then web front-end development might not be your bag. But a web-based graphical user interface (GUI) for administration and reporting for your microcontroller device can look very professional and be super useful. The
Mongoose Wizard
can help you develop a device dashboard for your ESP32-based project.
In this article (and
associated video
) the Mongoose developers run you through how to get started with their technology. They help you get your development environment set up, create your dashboard layout, add a dashboard page, add a device settings page, add an over-the-air (OTA) firmware update page, build and test the firmware, and attach the user-interface controls to the hardware. The generated firmware includes an embedded web server for serving your dashboard and delivering its REST interface, pretty handy.
You will find no end of ESP32-based projects here at Hackaday which you could potentially integrate with Mongoose. We think the OTA support is an excellent feature to have, but of course there are
other ways
of supporting that functionality.
Thanks to [Toly] for this tip. | 10 | 7 | [
{
"comment_id": "8126273",
"author": "Carl Breen",
"timestamp": "2025-05-10T09:43:33",
"content": "Needs a way to sign the firmware or only upload after authentication with a username and password on the flash menu in the browser. Other than that solid work. (watched without sound, if I missed that ... | 1,760,371,551.487792 | ||
https://hackaday.com/2025/05/09/the-apple-ii-mousecard-irq-is-synced-to-vertical-blanking-after-all/ | The Apple II MouseCard IRQ Is Synced To Vertical Blanking After All | Maya Posch | [
"Retrocomputing",
"Reverse Engineering"
] | [
"apple II",
"interrupts"
] | Recently [Colin Leroy-Mira]
found himself slipping into a bit of a rabbit hole
while investigating why only under Apple II MAME emulation there was a lot of flickering when using the (emulated) Apple II MouseCard. This issue could not be reproduced on real (PAL or NTSC) hardware. The answer all comes down to how the card synchronizes with the system’s vertical blanking (VBL) while drawing to the screen.
The Apple II MouseCard is one of the many
peripheral cards
produced for the system, originally bundled with a version of MacPaint for the Apple II. While not a super popular card at the time, it nevertheless got used by other software despite this Apple system still being based around a command line interface.
According to the card’s documentation the interrupt call (IRQ) can be set to 50 or 60 Hz to match the local standard. Confusingly, certain knowledgeable people told him that the card could not be synced to the VBL as it had no knowledge of this. As covered in the article and associated
MAME issue ticket
, it turns out that the card is very much synced with the VBL exactly as described in The Friendly Manual, with the card’s firmware being run by the system’s CPU, which informs the card of synchronization events. | 5 | 3 | [
{
"comment_id": "8126258",
"author": "Gravis",
"timestamp": "2025-05-10T06:58:44",
"content": "Defy the so-called experts!",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8126280",
"author": "Rastersoft",
"timestamp": "2025-05-10T10:45:35",
"content... | 1,760,371,551.962877 | ||
https://hackaday.com/2025/05/09/the-nuclear-war-you-didnt-notice/ | The Nuclear War You Didn’t Notice | Al Williams | [
"Science"
] | [
"cold war",
"cyclotron",
"periodic table",
"transfermium"
] | We always enjoy [The History Guy], and we wish he’d do more history of science and technology. But when he does, he always delivers! His latest video, which you can see below, focuses on the Cold War pursuit of creating
transfermium elements
. That is, the discovery of elements that appear above fermium using advanced techniques like cyclotrons.
There was a brief history of scientists producing unnatural elements. The two leaders in this work were a Soviet lab, the Joint Institute of Nuclear Research, and a US lab at Berkeley.
You’d think the discovery of new elements wouldn’t be very exciting. However, with the politics of the day, naming elements became a huge exercise in diplomacy.
Part of the problem was the difficulty in proving you created a huge atom for a few milliseconds. It was often the case that the initial inventor wasn’t entirely clear.
We were buoyed to learn that American scientists named an element(Mendelevium) after a Russian scientist as an act of friendship, although the good feelings didn’t last.
We wonder if a new element pops up, if we can get some votes for Hackadaium. Don’t laugh. You might not need a
cyclotron
anymore. | 7 | 5 | [
{
"comment_id": "8126218",
"author": "TG",
"timestamp": "2025-05-10T02:22:04",
"content": "The administrators and professors at Berkeley were heartwarmingly friendly with the Soviets? You don’t say! I’m shocked, I tell you!The header photo and the ones in the video are super cool. Can’t find any oth... | 1,760,371,551.716253 | ||
https://hackaday.com/2025/05/09/antique-mill-satisfies-food-cravings/ | Antique Mill Satisfies Food Cravings | Tyler August | [
"News"
] | [
"manual machining",
"pantograph",
"waffles breakfast"
] | Everyone knows what its like to get a hankering for a specific food. In [Attoparsec]’s case, he wanted waffles. Not any waffles would do, though; he needed waffles in the form of a labyrinth. Those don’t exist, so he had to
machine his own waffle maker
.
When computers were the size of rooms, these stood in where we’d use CNC today.
Most of us would have run this off on a CNC, but [Attoparsec] isn’t into CNCing–manual machining is his hobby, and he’s not interested in getting into another one, no matter how much more productive he admits it might make him. We can respect that. After a bit of brain sweat thinking of different ways to cut out the labyrinth shape, he has the opportunity to pick up an antique Deckle pantograph mill.
These machines were what shops used to do CNC before the ‘computer numeric’ part was a thing. By tracing out a template (which [Attoparsec] 3D prints, so he’s obviously no Luddite) complex shapes can be milled with ease. Complex shapes like a labyrnthine wafflemaker. Check out the full video below; it’s full of all sorts of interesting details about the machining process and the tools involved.
If you don’t need to machine cast iron, but are interested in the techniques seen here,
a wooden pantorouter might be more your speed
than a one-tonne antique. If you have a hankering for waffles but would rather use CNC, c
heck out these design tips
to help you get started. If pancakes are more your style,
why not print them
?
Shoutout to [the gambler] for sending this into the tip line. We think he struck the jackpot on this one. If you
have a tip, don’t be shy
. | 16 | 12 | [
{
"comment_id": "8126188",
"author": "Piecutter",
"timestamp": "2025-05-10T00:46:53",
"content": "Just to watch the syrup slowly find it’s way out.Excellent.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126392",
"author": "Hirudinea",
"tim... | 1,760,371,551.541245 | ||
https://hackaday.com/2025/05/09/inside-a-selective-voltmeter/ | Inside A Selective Voltmeter | Al Williams | [
"Repair Hacks",
"Teardown"
] | [
"Harmon",
"rms",
"selective voltmeter"
] | [Martin Lorton] has a vintage
Harmon 4200B selective voltmeter
that needed repair. He picked it up on eBay, and he knew it wasn’t working, but it was in good condition, especially for the price. He’s posted four videos about what’s inside and how he’s fixing it. You can see the first installment below.
The 4200B is an RMS voltmeter and is selective because it has a tuned circuit to adjust to a particular frequency. The unit uses discrete components and has an analog meter along with an LCD counter.
The initial tests didn’t work out well because the analog meter was stuck, so it wouldn’t go beyond about 33% of full scale.
Since there are four videos (so far), there is a good bit of information and detail about the meter. However, it is an interesting piece of gear and part 3 is interesting if you want to see inside an analog meter movement.
By the fourth video, things seem to be working well. You might want to browse the manual for the similar
4200A manual
to get oriented.
Forgot why we measure RMS? You
weren’t the only one
.
RMS conversion in meters
is a big topic and there are many ways to do it. | 0 | 0 | [] | 1,760,371,552.034203 | ||
https://hackaday.com/2025/05/09/a-single-chip-computer-for-the-8051-generation/ | A Single Chip Computer For The 8051 Generation | Jenny List | [
"classic hacks",
"Microcontrollers"
] | [
"8051",
"8052",
"MCS-51 BASIC"
] | The Intel 8051 series of 8-bit microcontrollers is long-discontinued by its original manufacturer, but lives on as a core included in all manner of more recent chips. It’s easy to understand and program, so it remains a fixture despite much faster replacements appearing.
If you can’t find an original 40-pin DIP don’t worry, because
[
mit41301
] has produced a board in a compatible 40-pin format
. It’s called the single chip computer not because such a thing is a novelty in 2025, but because it has no need for the support chips which would have come with the original.
The modern 8051 clone in use is a CH558 or CH559, both chips with far more onboard than the original. The pins are brought out to one side only of the board, because on the original the other side would interface with an external RAM chip. It speaks serial, and can be used through either a USB-to-serial or Bluetooth-to-serial chip. There’s MCS-BASIC for it, so programming should be straightforward.
We can see the attraction of this board even though we reach for much more accomplished modern CPUs by choice. Several decades ago the original 8051 on Intel dev boards was our university teaching microcontoller, so there remains here a soft spot for it. We certainly see other 8051 designs, as for example
this Arduino clone
. | 36 | 11 | [
{
"comment_id": "8126117",
"author": "deL",
"timestamp": "2025-05-09T19:05:59",
"content": "Starting out with a controller that features definite CPU-cycle and memory-resource constraints, will teach you a great deal about how to code efficiently. That’s something completely lost to the ‘programmers... | 1,760,371,552.149302 | ||
https://hackaday.com/2025/05/09/supercon-2024-an-immersive-motion-rehabilitation-device/ | Supercon 2024: An Immersive Motion Rehabilitation Device | Lewin Day | [
"cons",
"Hackaday Columns"
] | [
"2024 Hackaday Supercon",
"cons",
"medical device",
"rehabilitation"
] | When you’ve had some kind of injury, rehabilitation can be challenging. You often need to be careful about how you’re using the affected parts of your body, as well as pursue careful exercises for repair and restoration of function. It can be tedious and tiring work, for patients and treating practitioners alike.
Juan Diego Zambrano, Abdelrahman Farag, and Ivan Hernandez have been working on new technology to aid those going through this challenging process.
Their talk at the 2024 Hackaday Supercon
covers an innovative motion monitoring device intended to aid rehabilitation goals in a medical context.
Motion Project
As outlined in the talk, the team took a measured and reasoned approach to developing their device. The project started by defining the problem at hand, before proposing a potential solution. From there, it was a case of selecting the right hardware to do the job, and developing it alongside the necessary software to make it all work.
The Arduino Nano BLE33 had most of the necessary functionality for this project, out of the box.
The problem in question regarded helping children through rehabilitative therapies. Structured activities are used to help develop abilities in areas like motor skills, coordination, and balance. These can be particularly challenging for children with physical or developmental difficulties, and can be repetitive at the best of times, leading to a lack of engagement. “We wanted to solve that… we wanted to make it more interactive and more useful for the therapies and for the doctors,” Ivan explains, with an eye to increasing motivation for the individual undergoing rehabilitation.
Other challenges also exist in this arena. Traditional rehabilitation methods offer no real-time feedback to the individual on how they’re performing. There is also a need for manual monitoring and record keeping of the individual’s performance, which can be tedious and often relies on subjective assessments.
The device was demonstrated mounted on a patient’s chest, while being used in a game designed for balance work.
Having explored the literature on game-based therapy techniques, the team figured a wearable device with sensors could aid in solving some of these issues. Thus they created their immersive motion rehabilitation device.
At the heart of the build is an Arduino Nano BLE33, so named for its Bluetooth Low Energy wireless communications hardware. Onboard is an nRF52840 microcontroller, which offers both good performance and low power consumption. The real benefit of this platform, though, is that it includes an inertial measurement unit (IMU) and magnetometer on board and ready to go. The IMU in question is the BMI270, which combines a high-precision 3-axis accelerometer and 3-axis gyroscope into a single package. If you want to track motion in three dimensions, this is a great way to do it.
For user feedback, some additional hardware was needed. The team added a vibration motor, RGB LED, and buzzer for this reason. Controlling the device is simple, with the buttons on board. In order to make the device easy to use for therapists, it’s paired with a Windows application, programmed in C#. It’s used for monitoring and analysis of the wearer’s performance during regular rehabilitation activities.
The user’s motions are recorded while playing a simple game, providing useful clinical data.
The talk explains how this simple, off-the-shelf hardware was used to aid the rehabilitation experience. By gamifying things, users are prompted to better engage with the therapy process by completing tasks monitored by the device’s sensors. Fun graphics and simple gameplay ideas are used to make a boring exercise into something more palatable to children going through rehabilitation.
The team go on to explain the benefits on the clinical side of things, regarding how data collection and real time monitoring can aid in delivery. The project also involved the creation of a system for generating reports and accessing patient data to support this work, as well as a fun connection assistant called Sharky.
Overall, the talk serves as a useful insight as to how commonly-available hardware can be transformed into useful clinical tools. Indeed, it’s not so different from the gamification we see all the time in the exercise space, where smartwatches and apps are used to increase motivation and provide data for analysis. Ultimately, with a project like this, if you can motivate a patient to pursue their rehabilitation goals while collecting data at the same time, that’s useful in more ways than one. | 1 | 1 | [
{
"comment_id": "8126409",
"author": "Daniel Larrosa",
"timestamp": "2025-05-10T21:48:43",
"content": "Very nice project! Also useful and generous, for the benefit of those in need.The idea of gamification as a motivation for physiotherapy reminded me of something I read in the Reader’s Digest, ma... | 1,760,371,552.079099 | ||
https://hackaday.com/2025/05/08/diy-driving-simulator-pedals/ | DIY Driving Simulator Pedals | Matthew Carlson | [
"Peripherals Hacks"
] | [
"3d printed",
"foot pedals",
"racing simulation"
] | In the driving simulator community, setups can quickly grow ever more complicated and expensive, all in the quest for fidelity. For [CNCDan], rather than buy pedals off the shelf, he
opted to build his own
.
[Dan] has been using some commercial pedals alongside his own DIY steering wheel and the experience is rather lackluster in comparison. The build starts with some custom brackets. To save on cost, they are flat with tabs to let you know where to bend it in a vise. Additionally, rather than three sets of unique brackets, [Dan] made them all the same to save on cost. The clutch and throttle are a simple hall effect sensor with a spring to provide feedback. However, each bracket provides a set of spring mounting holes to adjust the curve. Change up the angle of the spring and you have a different curve. The brake pedal is different as rather than measure position, it measures force. A load cell is perfect for this. The HX711 load cell sensor board that [Dan] bought was only polling at 10hz. Lifting a pin from ground and bodging it to VDD puts the chip in 80hz, which is much more usable for a driving sim setup.
[Dan] also cleverly uses a 3d printed bushing without any walls as resistance for the pedal. Since the bushing is just the infill, the bushing stiffness is controlled by the infill percentage. Aluminum extrusion forms the base so [Dan] can adjust the exact pedal positions. To finish it off, a bog standard Arduino communicates to the PC as a game controller.
The
project is on GitHub
. Perhaps the next version will have active feedback,
like this DIY pedal setup
. | 8 | 5 | [
{
"comment_id": "8125842",
"author": "Miles",
"timestamp": "2025-05-08T23:58:15",
"content": "Bottom hinged pedals allow the foot to actuate the pedal in an arc similar to the one your ankle moves in.Activating them from school bus driving seat height and too far away is cringe.🤷🏼♂️ To each their... | 1,760,371,552.315811 | ||
https://hackaday.com/2025/05/08/edison-phonograph-plays-the-cylinders/ | Edison Phonograph Plays The Cylinders | Al Williams | [
"home entertainment hacks"
] | [
"amberol",
"edison",
"phonograph"
] | You might be old enough to remember record platters, but you probably aren’t old enough to remember when records were cylinders. The Edison Blue Amberol records came out in 1912 and were far superior to the earlier wax cylinders. If you had one today, how could you play it? Easy. Just build [Palingenesis’]
record player
. You can even hear it do its thing in the video below.
The cylinders are made of plaster with a celluloid wrapper tinted with the namesake blue color. They were more durable than the old wax records and could hold well over four minutes of sound.
The player is mostly made from wood cut with a mill or a laser. There are some bearings, fasteners, and — of course — electronics. The stylus requires some care. Conventional records use a lateral-cut groove, but these old records use a vertical-cut. That means the pickup moves up and down and has a rounder tip than a conventional needle.
Rather than try to control the motor to an exact speed, you get to set the speed with a potentiometer and see the resulting RPM on a small display. Overall, an involved but worthwhile project.
We recently looked at some
players
that would have been new about the same time as the blue record in the video. We don’t think you could modify one of these to play
stereo
, but if you do, let us know immediately! | 9 | 8 | [
{
"comment_id": "8125786",
"author": "Jonathan Whitaker",
"timestamp": "2025-05-08T20:07:58",
"content": "Good timing! I started trying to cobble together a player yesterday, now I have a reference 😁",
"parent_id": null,
"depth": 1,
"replies": []
},
{
"comment_id": "8125808",
... | 1,760,371,552.273512 | ||
https://hackaday.com/2025/05/08/let-the-wookie-win-with-this-diy-holochess-table/ | Let The Wookie Win With This DIY Holochess Table | Tyler August | [
"Games",
"hardware"
] | [
"chess board",
"holographic",
"holographic display",
"star wars",
"volumetric display"
] | If you have seen
Star Wars
, you know what is being referenced here. Holochess appeared as a diversion built into the Millennium Falcon in the very first movie, way back in 1977. While not quite as iconic a use of simulated holograms as tiny Princess Leia begging for hope, it evidently struck a chord with [Maker Mac70], given the impressive effort he’s evidently gone through to
re-create the game table from the film.
The key component of this unit is a plate from Japanese firm ASKA3D that scatters light from displays inside the table in just such a way that the diverging rays are focused at a point above its surface, creating the illusion of an image hovering in space. Or in this case, hovering at the surface of a acrylic chessboard. Granted, this technique only works from one viewing angle, and so is not a perfect recreation of a sci-fi holoprojector. But from the right angle, it looks
really
good, as you can see in the video below.
There are actually six SPI displays, driven by an Arduino GIGA, positioned and angled to project each character in the game. Placing two of the displays on 3D printed gantries allows them to move, allowing two creatures to battle in the center of the table. As [Maker Mac70] admits, this is quite a bit simpler than the Holochess game seen in the film, but it’s quite impressive for real world hardware.
If this all seems a little bit familiar, we covered
an earlier floating display
by [Maker Mac70] last year. This works on similar principles, but uses more common components which makes the technique more accessible. If chess isn’t your forte, why not
a volumetric display that plays
DOOM
? If you’re interested in real holograms, not Sci-Fi, our own [Maya Posch] did a
deep dive you may find interesting
. | 9 | 4 | [
{
"comment_id": "8125767",
"author": "Igor",
"timestamp": "2025-05-08T19:13:57",
"content": "You only need a wookie to play with",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8126963",
"author": "scott_tx",
"timestamp": "2025-05-12T19:18:07"... | 1,760,371,552.471274 | ||
https://hackaday.com/2025/05/08/the-owon-hds160-reviewed/ | The Owon HDS160 Reviewed | Al Williams | [
"Reviews",
"Teardown"
] | [
"HDS160",
"oscilloscope",
"owon",
"scopemeter"
] | These days, if you are in the market for a capable digital voltmeter, you might as well consider getting one with an oscilloscope built-in. One choice is the
Owon HDS160
, which [Kerry Wong] covers in the video below. The model is very similar to the HDS120, but the multimeter in the HDS160 has more counts–60,000 vs 20,000 as you might expect from the model number.
The internal chip is an HY3131, which is rated at 50,000 counts which is odd since the meter is 60,000 counts, but presumably the meter uses some capability of the chip, possibly putting it out of spec. The oscilloscope is the same between the two models. Almost everything else works the same, other than the capacitance measuring feature, as the video shows.
The difference in cost between the two units isn’t much, so if you are shopping, the small extra cost is probably worth it. Not that a 20,000 count meter isn’t perfectly fine for most normal uses.
[Kerry] really
likes scopemeters
. He gets excited about
bench scopes
, too. | 11 | 2 | [
{
"comment_id": "8125696",
"author": "Sok Puppette",
"timestamp": "2025-05-08T15:55:52",
"content": "The internal chip is an HY3131, which is rated at 50,000 counts which is odd since the meter is 60,000 counts, but presumably the meter uses some capability of the chip, possibly putting it out of sp... | 1,760,371,552.517706 | ||
https://hackaday.com/2025/05/08/flow-visualization-with-schlieren-photography/ | Flow Visualization With Schlieren Photography | Tyler August | [
"Featured",
"Interest",
"Original Art"
] | [
"photography",
"Schlieren",
"science",
"shimmer"
] | The word “Schlieren” is German, and translates roughly to “streaks”. What is streaky photography, and why might you want to use it in a project? And where did this funny term come from?
Think of the heat shimmer you can see on a hot day. From the ideal gas law, we know that hot air is less dense than cold air. Because of that density difference, it has a slightly lower refractive index. A light ray passing through a density gradient faces a gradient of refractive index, so is bent, hence the shimmer.
Heat shimmer: the refractive index of the air is all over the place. Image:
“Livestock crossing the road in Queensland, Australia”
by [AlphaLemur]
German lens-makers started talking about “Schelieren” sometime in the 19
th
century, if not before. Put yourself in the shoes of an early lensmaker: you’ve spent countless hours laboriously grinding away at a glass blank until it achieves the perfect curvature. Washing it clean of grit, you hold it to the light and you see aberration — maybe spatial, maybe chromatic.
Schliere
is the least colourful word you might say, but a
schliere
is at fault. Any wonder lens makers started to develop techniques to detect the invisible flaws they called
schlieren?
When we talk of schlieren imagery today, we generally aren’t talking about inspecting glass blanks. Most of the time, we’re talking about a family of fluid-visualization techniques. We owe that nomenclature to German physicist August Toepler, who applied these optical techniques to visualizing fluid flow in the middle of the 19
th
century. There is now a whole family of schlieren imaging techniques, but at the core, they all rely on one simple fact: in a fluid like air, refractive index varies by density.
Toepler’s pioneering setup is the one we usually see in
hacks nowadays
. It is based on the
Foucault Knife Edge Test
for telescope mirrors. In Foucault’s test, a point source shines upon a concave mirror, and a razor blade is placed where the rays focus down to a point. The sensor, or Foucault’s eye, is behind the knife edge such that the returning light from the pinhole is interrupted. This has the effect of magnifying any flaws in the lens, because rays that deviate from the perfect return path will be blocked by the knife-edge and miss the eye.
[Toepler]’s single-mirror layout is quick and easy.
Toepler’s photographic setup worked the same way, save for the replacement of the eye with a photographic camera, and the use of a known-good mirror. Any density changes in the air will refract the returning rays, and cause the characteristic light and dark patterns of a schlieren photograph. That’s the “classic” schlieren we’ve covered before, but it’s not the only game in town.
Fun Schlieren Tricks
A little color can make a big difference for any kind of visualization. (Image:
“
Colored schlieren image
“
by [Settles1])
For example, a small tweak that makes a big aesthetic difference is to replace the knife edge with a colour filter. The refracted rays then take on the colour of the filter. Indeed, with a couple of colour filters you can colour-code density variations: light that passes through high-density areas can be diverted through two different colored filters on either side, and the unbent rays can pass through a third. Not only is it very pretty, the human eye has an easier time picking up on variations in colour than value. Alternatively, the light from the point source can be passed through a prism. The linear spread of the frequencies from the prism has a similar effect to a line of colour filters: distortion gets color-coded.
A bigger tweak uses two convex mirrors, in two-mirror or Z-path schlieren. This has two main advantages: one, the parallel rays between the mirrors mean the test area can be behind glass, useful for keeping sensitive optics outside of a high-speed wind tunnel. (
This is the technique NASA used to use
.) Parallel rays also ensure that the shadow of both any objects and the fluid flow are no issue; having the light source off-centre in the classic schrilien can cause artifacts from shadows. Of course you pay for these advantages: literally, in the sense that you have to buy two mirrors, and figuratively in that alignment is twice as tricky. The same colour tricks work just as well, though, and was in often use at NASA.
The z-fold allows for parallel rays in the test area.
There’s absolutely no reason that you could not substitute lenses for mirrors, in either the Z-path or classical version, and people have to good effect in both cases. Indeed, Robert Hooke’s first experiment involved visualizing the flow of air above a candle using a converging lens, which was optically equivalent to Toepler’s classic single-mirror setup. Generally speaking, mirrors are preferred for the same reason you never see an 8” refracting telescope at a star party: big mirrors are way easier to make than large lenses.
T-38s captured in flight with NASA’s AirBOS technique. Image credit : NASA.
What if you want to visualize something that doesn’t fit in front of a mirror? There are actually several options. One is background-oriented schrilien,
which we’ve covered here.
With a known background, deviations from it can be extracted using digital signal processing techniques. We showed it working with a smart phone and a printed page, but you can use any non-uniform background. NASA uses the ground: by looking down,
Airborn Background Oriented Schlieren (AirBOS)
can provide flow visualization of shockwaves and vortices around an airplane in flight.
In the days before we all had supercomputers in our pockets, large-scale flow-visualization was still possible; it just needed an optical trick. A pair of matching grids is needed: one before the lamp, creating a projection of light and dark, and a second one before the lens. Rays deflected by density variations will run into the camera grid. This was used to good effect by Gary S. Styles
to visualize HVAC airflows in 1997
Can’t find a big mirror? Try a grid.
Which gets us to another application, separate from aerospace. Wind tunnel photos are very cool, but let’s be honest: most of us are not working on supersonic drones or rocket nozzles. Of course air flow does not have to be supersonic to create density variations; subsonic wind tunnels can be equipped with schlieren optics as well.
HVAC as you’ve never seen it before. Imagine those were ABS fumes? (Image from
Styles, 1997
.)
Or maybe you are more concerned with airflow around components? To ID a hotspot on a board, IR photography is much easier. On the other hand, if your hotspot is due to insufficient cooling rather than component failure? Schlieren imagery can help you visualize the flow of air around the board, letting you optimize the cooling paths.
That’s probably going to be easiest with the background-oriented version: you can just stick the background on one side of your project’s enclosure and go to work. I think that if any of you start using schlieren imaging in your projects, this might be the killer app that will inspire you to do so.
Another place we use air? In the maker space. I have yet to see someone use schlieren photography to tweak the cooling ducts on their 3D printer, but you certainly
could
. (It has been used to see
shielding gasses in welding, for example
.) For that matter, depending what you print, proper exhaust of the fumes is a major health concern. Those fumes will show up easily, given the temperature difference, and possibly even the chemical composition changing the density of the air.
Remember that the key thing being imaged isn’t temperature difference, but density difference. Sound waves are density waves, can they be imaged in this way? Yes! The standing waves in
ultrasonic levitation rigs
are a popular target. Stroboscopic effects can be used for non-standing waves, though keep in mind that the sound pressure level is the inverse of frequency, so audible frequencies
may not be practical if you like your eardrums.
Image from [wolfgang]’s
excellent Harvard Physics demo video.
Sugar water (from the disolving cube) is higher in density than pure water. Image from Shell Historical Film Archive.
Schlieren photography isn’t limited to air. Density variations in liquids and solids are game, too. Want to see how multiple solutions of varying density or tempeature are mixing? Schlieren imaging has you covered. Watch convection in a water tank? Or, if you happen to be making lenses, you could go right back to basics and use one of the schlieren techniques discussed here to help you make them perfect.
The real reason I’m writing about these techniques aren’t the varied applications I hope you hackers can put them to: it’s an excuse to collect all the pretty pictures of flow visualization I can cram into this article. So if you read this and thought “I have no practical reason to use this technique, but it does seem cool” – great! We’re in the same boat. Let’s make some pretty pictures. It still counts as a hack. | 9 | 6 | [
{
"comment_id": "8125681",
"author": "Meek the Geek",
"timestamp": "2025-05-08T14:44:29",
"content": "After seeing the video seeing the invisible by Physics explainedhttps://youtu.be/GCloRHSyaGU?si=WP0jMG2irE3eJ35GI had to try building the setup for our Physics lab as a demonstration. I will try th... | 1,760,371,552.424173 | ||
https://hackaday.com/2025/05/08/a-constant-fraction-discriminator-for-sub-nanosecond-timing/ | A Constant-Fraction Discriminator For Sub-Nanosecond Timing | Aaron Beckendorf | [
"hardware"
] | [
"constant fraction discriminator",
"pulse",
"signal processing"
] | Detecting a signal pulse is usually basic electronics, but you start to find more complications when you need to time the signal’s arrival in the picoseconds domain. These include the time-walk effect: if your circuit compares the input with a set threshold, a stronger signal will cross the threshold faster than a weaker signal arriving at the same time, so stronger signals seem to arrive faster. A constant-fraction discriminator solves this by triggering at a constant fraction of the signal pulse, and [Michael Wiebusch] recently presented a
hacker-friendly implementation
of the design (
open-access paper
).
A constant-fraction discriminator splits the input signal into two components, inverts one component and attenuates it, and delays the other component by a predetermined amount. The sum of these components always crosses zero at a fixed fraction of the original pulse. Instead of checking for a voltage threshold, the processing circuitry detects this zero-crossing. Unfortunately, these circuits tend to require very fast (read “expensive”) operational amplifiers.
This is where [Michael]’s design shines: it uses only a few cheap integrated circuits and transistors, some resistors and capacitors, a length of coaxial line as a delay, and absolutely no op-amps. This circuit has remarkable precision, with a timing standard deviation of 60 picoseconds. The only downside is that the circuit has to be designed to work with a particular signal pulse length, but the basic design should be widely adaptable for different pulses.
[Michael] designed this circuit for a gamma-ray spectrometer, of which
we’ve seen
a
few examples
before. In a spectrometer, the discriminator would process signals from
photomultiplier tubes
or
scintillators
, such as we’ve covered before. | 3 | 2 | [
{
"comment_id": "8125637",
"author": "Ostracus",
"timestamp": "2025-05-08T12:09:01",
"content": "Proper component matching and layout for consistent timing and impedance matching to avoid reflections in delay line. A clean source would work better, maybe some analog clamping or RC differentiators?"... | 1,760,371,552.559399 | ||
https://hackaday.com/2025/05/08/3d-printed-tpu-bellows-with-pla-interface-layers/ | 3D Printed TPU Bellows With PLA Interface Layers | Maya Posch | [
"3d Printer hacks"
] | [
"bellows",
"TPU"
] | Of all FDM filament types, flexible ones such as TPU invite a whole new way of thinking, as well as applications. Case in point the
TPU-based bellows
that the [Functional Part Friday] channel on YouTube recently demonstrated.
The idea is quite straightforward: you print TPU and PLA in alternating layers, making sure that the TPU is connected to its previous layer in an alternating fashion. After printing, you peel the PLA and TPU apart, remove the PLA layers and presto, you got yourself bellows.
There were some issues along the way, of course. Case in point the differences between TPU from different brands (Sainsmart, Sunlu) that caused some headaches, and most of all the incompatibility between the Bambu Lab AMS and TPU that led to incredibly brittle TPU prints. This required bypassing the feed mechanism in the AMS, which subsequently went down a rabbit hole of preventing the PTFE tube from getting sucked into the AMS. Being able to print TPU & PLA at the same time also requires a printer with two independent extruders like the Bambu Lab H2D used here, as both materials do not mix in any way. Great news for H2D and IDEX printer owners, of course.
As for practical applications for bellows, beyond printing your own 1900s-era camera, accordion or hand air bellows, you can also create lathe way covers and so on. | 22 | 8 | [
{
"comment_id": "8125583",
"author": "Krzysztof",
"timestamp": "2025-05-08T08:29:43",
"content": "Great idea for all those soft robot actuators!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125614",
"author": "helge",
"timestamp": "2025-05... | 1,760,371,552.754338 | ||
https://hackaday.com/2025/05/09/hackaday-podcast-episode-320-a-lot-of-cool-3d-printing-diy-penicillin-and-an-optical-twofer/ | Hackaday Podcast Episode 320: A Lot Of Cool 3D Printing, DIY Penicillin, And An Optical Twofer | Kristina Panos | [
"Hackaday Columns",
"Podcasts"
] | [
"Hackaday Podcast"
] | This week, Hackaday’s Elliot Williams and Kristina Panos met up across the universe to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.
In Hackaday news,
the 2025 Pet Hacks Contest
rolls on. You have until June 10th to show us what you’ve got, so head over to Hackaday.IO and get started today!
On What’s That Sound, Kristina actually got it this time, although she couldn’t quite muster the correct name for it, however at Hackaday we’ll be calling it the “glassophone” from now on. Congratulations to [disaster_recovered] who fared better and wins a limited edition Hackaday Podcast t-shirt!
After that, it’s on to the hacks and such, beginning with a complete and completely-documented wireless USB autopsy. We take a look at a lovely 3D-printed downspout, some DIY penicillin, and a jellybean iMac that’s hiding a modern PC. Finally, we explore a really cool 3D printing technology, and ask what happened to typing ‘www.’.
Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Download in
DRM-free MP3
and savor at your leisure.
Where to Follow Hackaday Podcast
Places to follow Hackaday podcasts:
iTunes
Spotify
Stitcher
RSS
YouTube
Check
out our Libsyn landing page
Episode 320 Show Notes:
News:
The Pet Hacks Challenge rolls on!
What’s that Sound?
Congratulations to [disaster_recovered] for the glass armonica pick!
Interesting Hacks of the Week:
Wireless USB Autopsy
3D Printed Downspout Makes Life Just A Little Nicer
DIY Penicillin
Jellybean Mac Hides Modern PC
Liquid Silicone 3D Printing Is No Joke
Creative PCB Business Cards Are Sure To Make An Impression
Quick Hacks:
Elliot’s Picks:
3D Printed TPU Bellows With PLA Interface Layers
Germany’s Cabinentaxi: The Double-Sided Monorail That Wasn’t Meant To Be
PCB Renewal Aims To Make Old Boards Useful Again
Kristina’s Picks:
A Neat E-Paper Digit Clock (or Four)
All-Band Radio Records Signals, Plays MP3s
3D Printed Spirograph Makes Art Out Of Walnut
Can’t-Miss Articles:
Optical Contact Bonding: Where The Macro Meets The Molecular
Flow Visualization With Schlieren Photography
What Happened To WWW.? | 0 | 0 | [] | 1,760,371,552.601848 | ||
https://hackaday.com/2025/05/09/oscilloscope-digital-storage-1990s-style/ | Oscilloscope Digital Storage, 1990s Style | Al Williams | [
"Teardown",
"Tool Hacks"
] | [
"analog shift register",
"oscilloscope",
"tektronix"
] | You’re designing an oscilloscope with modest storage — only 15,000 samples per channel. However, the sample rate is at 5 Gs/s, and you have to store all four channels at that speed and depth. While there is a bit of a challenge implied, this is quite doable using today’s technology. But what about in the 1990s when
the Tektronix TDS 684B
appeared on the market? [Tom Verbure] wondered how it was able to do such a thing. He found out, and since he wrote it up, now you can find out, too.
Inside the scope, there are two PCBs. There’s a CPU board, of course. But there’s not enough memory there to account for the scope’s capability. That much high-speed memory would have been tough in those days, anyway. The memory is actually on the analog board along with the inputs and digitizers. That should be a clue.
The secret is the ADG286D from National Semiconductor. While we can’t find any info on the chip, it appears to be an analog shift register, something all the rage at the time. These chips often appeared in audio special effect units because they could delay an analog signal easily.
In practice, the device worked by charging a capacitor to an input signal and then, using a clock, dumping each capacitor into the next one until the last capacitor produced the delayed output. Like any delay line, you could feed the output to the input and have a working memory device.
The scope would push samples into the memory at high speed. Then the CPU could shift them back out on a much slower clock. A clever design and [Tom] gives us a great glimpse inside a state-of-the-art 1990s-era scope.
While we haven’t seen the ADG286D before, we have looked at
analog shift registers
, if you want to learn more. | 13 | 6 | [
{
"comment_id": "8126045",
"author": "MattAtHazmat",
"timestamp": "2025-05-09T15:54:00",
"content": "Great series of scopes- I think they are the last Tek series that were not Windows based- And many in the series could get a memory upgrade by the FAE running a disk- Had to buy this from Tek about ... | 1,760,371,552.693572 | ||
https://hackaday.com/2025/05/09/this-week-in-security-encrypted-messaging-nsos-judgement-and-ai-cve-ddos/ | This Week In Security: Encrypted Messaging, NSO’s Judgement, And AI CVE DDoS | Jonathan Bennett | [
"Hackaday Columns",
"News",
"Security Hacks"
] | [
"ai",
"CVEs",
"supply chain attack",
"This Week in Security"
] | Cryptographic messaging has been in the news a lot recently. Like
the formal audit of WhatsApp
(
the actual PDF
). And the results are good. There are some minor potential problems that the audit highlights, but they are of questionable real-world impact. The most consequential is how easy it is to add additional members to a group chat. Or to put it another way, there are no cryptographic guarantees associated with adding a new user to a group.
The good news is that WhatsApp groups don’t allow new members to read previous messages. So a user getting added to a group doesn’t reveal historic messages. But a user added without being noticed can snoop on future messages. There’s an obvious question, as to how this is a weakness. Isn’t it redundant, since anyone with the permission to add someone to a group, can already read the messages from that group?
That’s where the lack of cryptography comes in. To put it simply, the WhatsApp servers could add users to groups, even if none of the existing users actually requested the addition. It’s not a vulnerability per se, but definitely a design choice to keep in mind. Keep an eye on the members in your groups, just in case.
The Signal We Have at Home
The TeleMessage app has been pulled from availability, after
it was used to compromise Signal communications of US government officials
. There’s political hay to be made out of the current administration’s use and potential misuse of Signal, but the political angle isn’t what we’re here for. The TeleMessage client is Signal compatible, but adds message archiving features. Government officials and financial companies were using this alternative client, likely in order to comply with message retention laws.
While it’s possible to do long term message retention securely, TeleMessage was not doing this particularly well. The messages are stripped of their end-to-end encryption in the client, before being sent to the archiving server. It’s not clear exactly how, but those messages were accessed by a hacker. This nicely demonstrates the inherent tension between the need for transparent archiving as required by the US government for internal communications, and the need for end-to-end encryption.
The NSO Judgement
WhatsApp is in the news for another reason, this time
winning a legal judgement against NSO Group
for their Pegasus spyware. The
$167 Million in damages casts real doubt
on the idea that NSO has immunity to develop and deploy malware, simply because it’s doing so for governments. This case is likely to be appealed, and higher courts may have a different opinion on this key legal question, so hold on. Regardless, the era of NSO’s nearly unrestricted actions is probably over. They aren’t the only group operating in this grey legal space, and the other “legal” spyware/malware vendors are sure to be paying attention to this ruling as well.
The $5 Wrench
In reality,
the weak point of any cryptography scheme is the humans using it
. We’re beginning to see real world re-enactments of
the famous XKCD $5 wrench
, that can defeat even 4096-bit RSA encryption. In this case, it’s the application of old crime techniques to new technology like cryptocurrency. To quote Ars Technica:
We have reached the “severed fingers and abductions” stage of the crypto revolution
The flashy stories involve kidnapping and torture, but let’s not forget that the most common low-tech approach is simple deception. Whether you call it the art of the con, or social engineering, this is still the most likely way to lose your savings, whether it’s conventional or a cryptocurrency.
The SonicWall N-day
WatchTowr is back with
yet another reverse-engineered vulnerability
. More precisely, it’s two CVEs that are being chained together to achieve pre-auth Remote Code Execution (RCE) on SonicWall appliances. This exploit chain has been patched, but not everyone has updated, and the vulnerabilities are being exploited in the wild.
The first vulnerability at play is actually from last year, and is in Apache’s
mod_rewrite
module. This module is widely used to map URLs to source files, and it has a filename confusion issue where a url-encoded question mark in the path can break the mapping to the final filesystem path. A second issue is that when
DocumentRoot
is specified, instances of
RewriteRule
take on a weird dual-meaning. The filesystem target refers to the location inside
DocumentRoot
, but it first checks for that location in the filesystem root itself. This was fixed in Apache nearly a year ago, but it takes time for patches to roll out.
SonicWall was using a rewrite rule to serve CSS files, and the regex used to match those files is just flexible enough to be abused for arbitrary file read.
/mnt/ram/var/log/httpd.log%3f.1.1.1.1a-1.css
matches that rule, but includes the url-encoded question mark, and matches a location on the root filesystem. There are other, more interesting files to access, like the
temp.db
SQLite database, which contains session keys for the currently logged in users.
The other half of this attack is a really clever command injection using one of the diagnostic tools included in the SonicWall interface.
Traceroute6
is straightforward, running a traceroute6 command and returning the results. It’s also got good data sanitization, blocking all of the easy ways to break out of the
traceroute
command and execute some arbitrary code. The weakness is that while this sanitization adds backslashes to escape quotes and other special symbols, it stores the result in a fixed-length result buffer. If the result of this escaping process overflows the result buffer, it writes over the null terminator and into the buffer that holds the original command before it’s sanitized. This overflow is repeated when the command is run, and with some careful crafting, this results in escaping the sanitization and including arbitrary commands. Clever.
The AI CVE DDoS
[Daniel Stenberg], lead developer of curl, is putting his foot down
. We’ve talked about this before, even chatting with Daniel about the issue when
we had him on FLOSS Weekly
. Curl’s bug bounty project has attracted quite a few ambitious people, that don’t actually have the skills to find vulnerabilities in the curl codebase. Instead, these amateur security researchers are using LLMs to “find vulnerabilities”. Spoiler, LLMs aren’t yet capable of this task. But LLMs are capable of writing
fake vulnerability reports that look very convincing at first read
. The game is usually revealed when the project asks a question, and the fake researcher feeds the LLM response back into the bug report.
This trend hasn’t slowed, and the curl project is now
viewing the AI generated vulnerability reports as a form of DDoS
. In response, the curl Hackerone bounty program will soon ask a question with every entry: “Did you use an AI to find the problem or generate this submission?” An affirmative answer won’t automatically disqualify the report, but it definitely puts the burden on the reporter to demonstrate that the flaw is real and wasn’t hallucinated. Additionally, “AI slop” reports will result in permanent bans for the reporter.
It’s good to see that not all AI content is completely disallowed, as it’s very likely that LLMs
will
be involved in finding and describing vulnerabilities before long. Just not in this naive way, where a single prompt results in a vulnerability find and generates a patch that doesn’t even apply. Ironically, one of the tells of an AI generated report is that it’s too perfect, particularly for someone’s first report. AI is still the hot new thing, so this issue likely isn’t going away any time soon.
Bits and Bytes
A supply chain attack has
been triggered against several hundred Magento e-commerce sites
, via at least three software vendors distributing malicious code. One of the very odd elements to this story is that it appears this malicious code has been incubating for six years, and only recently invoked for malicious behavior.
On the WordPress side of the fence,
the Ottokit plugin was updated last month to fix a critical vulnerability
. That update was force pushed to the majority of WordPress sites running that plugin, but that hasn’t stopped threat actors from attempting to use the exploit, with
the first attempts coming just an hour and a half after disclosure
.
It turns out
it’s probably not a great idea to allow control codes as part of file names
. Portswigger has a report of a couple ways VS Code can do the wrong thing with such filenames.
And finally, this story comes with a disclaimer: Your author is part of Meshtastic Solutions and the Meshtastic project. We’ve talked about Meshtastic a few times here on Hackaday, and would be remiss not to point out
CVE-2025-24797
. This buffer overflow could theoretically result in RCE on the node itself. I’ve seen at least one suggestion that this is a wormable vulnerability, which may be technically true, but seems quite impractical in practice. Upgrade your nodes to at least release 2.6.2 to get the fix. | 3 | 1 | [
{
"comment_id": "8126162",
"author": "limroh",
"timestamp": "2025-05-09T22:47:07",
"content": "This nicely demonstrates the inherent tension between the need for transparent archiving as required by the US government for internal communications, and the need for end-to-end encryption.How does this d... | 1,760,371,552.797165 | ||
https://hackaday.com/2025/05/09/triggering-lightning-and-safely-guiding-it-using-a-drone/ | Triggering Lightning And Safely Guiding It Using A Drone | Maya Posch | [
"drone hacks",
"Science"
] | [
"drone",
"lightning"
] | Every year lightning strikes cause a lot of damage — with the high-voltage discharges being a major risk to buildings, infrastructure, and the continued existence of squishy bags of mostly salty water. While some ways exist to reduce their impact such as lightning rods, these passive systems can only be deployed in select locations and cannot prevent the build-up of the charge that leads up to the plasma discharge event. But the
drone-based system recently tested
by Japan’s NTT
,
the world’s fourth largest telecommunications company, could provide a more proactive solution.
The idea is pretty simple: fly a drone that is protected by a specially designed metal cage close to a thundercloud with a conductive tether leading back to the ground. By providing a very short path to ground, the built-up charge in said cloud will readily discharge into this cage and from there back to the ground.
To test this idea, NTT researchers took commercial drones fitted with such a protective cage and exposed them to artificial lightning. The drones turned out to be fine up to 150 kA which is five times more than natural lightning. Afterwards the full system was tested with a real thunderstorm, during which the drone took a hit and kept flying, although the protective cage partially melted.
Expanding on this experiment, NTT imagines that a system like this could protect cities and sensitive areas, and possibly even use and store the thus captured energy rather than just leading it to ground. While this latter idea would need some seriously effective charging technologies, the idea of proactively discharging thunderclouds is perhaps not so crazy. We would need to see someone run the numbers on the potential effectiveness, of course, but we are all in favor of (safe) lightning experiments like this.
If you’re wondering why channeling lightning away from critical infrastructure is such a big deal,
you may want to read up on Apollo 12
. | 43 | 12 | [
{
"comment_id": "8125953",
"author": "shinsukke",
"timestamp": "2025-05-09T11:55:27",
"content": "The drones turned out to be fine up to 150 kA which is five times more than natural lightningThat means natural lightning is 30kA. I always imagined it to be a lot more, for whatever reason. Something l... | 1,760,371,552.939667 | ||
https://hackaday.com/2025/05/09/scan-your-caliper-for-physical-part-copies/ | Scan Your Caliper For Physical Part Copies | Al Williams | [
"3d Printer hacks"
] | [
"3d printing",
"cad"
] | We’ve certainly seen people take a photo of a part, bring it into CAD, and then scale it until some dimension on the screen is the same as a known dimension of the part. We like what [Scale Addition] shows in the video below. In addition to a picture of the part, he also
takes a picture of a vernier caliper gripping the part
. Now your scale is built into the picture, and you can edit out the caliper later.
He uses SketchUp, but this would work on any software that can import an image. Given the image with the correct scale, it is usually trivial to sketch over the image or even use an automatic tracing function. You still need some measurements, of course. The part in question has a vertical portion that doesn’t show up in a flat photograph. We’ve had good luck using a flatbed scanner before, and there’s no reason you couldn’t scan a part with a caliper for scale.
This is one case where a digital caliper probably isn’t as handy as an old-school one. But it would be possible to do the same trick with any measurement device. You could even take your picture on a grid of known dimensions. This would also allow you to check that the distances at the top and bottom are the same as the distances on the right and left.
Of course, you can get 3D scanners, but they have
their own challenges
. | 60 | 13 | [
{
"comment_id": "8125900",
"author": "Michael Karliner",
"timestamp": "2025-05-09T08:15:10",
"content": "When I need to copy a part that may be in a location away from my workbench, I just photo it with a £1 coin for scale (other currencies are available).",
"parent_id": null,
"depth": 1,
... | 1,760,371,553.114349 | ||
https://hackaday.com/2025/05/08/hacky-shack-the-trs-80-model-i-story/ | Hacky Shack? The TRS-80 Model I Story | Maya Posch | [
"Retrocomputing"
] | [
"tandy",
"trs-80"
] | The 1970s saw a veritable goldrush to corner the home computer market, with Tandy’s Z80-powered TRS-80 probably one of the most (in)famous entries. Designed from the ground up to be as cheap as possible, the original (Model I) TRS-80 cut all corners management could get away with. The story of the TRS-80 Model I is the
subject of a recent video
by the [Little Car] YouTube channel.
Having the
TRS-80
sold as an assembled computer was not a given, as kits were rather common back then, especially since Tandy’s Radio Shack stores had their roots in selling radio kits and the like, not computer systems. Ultimately the system was built around the lower-end 1.78 MHz Z80 MPU with the rudimentary
Level I BASIC
(later updated to Level II), though with a memory layout that made running the likes of CP/M impossible. The Model II would be sold later as a dedicated business machine, with the Model III being the actual upgrade to the Model I. You could also absolutely access online services like
those of Compuserve
on your TRS-80.
While it was appreciated that the TRS-80 (lovingly called the ‘Trash-80’ by some) had a real keyboard instead of a cheap membrane keyboard, the rest of the Model I hardware had plenty of issues, and new FCC regulations meant that the Model III was required as the Model I produced enough EMI to drown out nearby radios. Despite this, the Model I put Tandy on the map of home computers, opened the world of computing to many children and adults, with subsequent Tandy TRS-80 computers being released until 1991 with the
Model 4
. | 44 | 19 | [
{
"comment_id": "8125885",
"author": "Ostracus",
"timestamp": "2025-05-09T06:01:18",
"content": "Trash-80 indeed. One look from me across the room and it rebooted, losing work.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125988",
"author": "ziggu... | 1,760,371,553.022833 | ||
https://hackaday.com/2025/05/08/understanding-linear-regression/ | Understanding Linear Regression | Al Williams | [
"Machine Learning"
] | [
"linear regression",
"math"
] | Although [Vitor Fróis] is explaining
linear regression
because it relates to machine learning, the post and, indeed, the topic have wide applications in many things that we do with electronics and computers. It is one way to use independent variables to predict dependent variables, and, in its simplest form, it is based on nothing more than a straight line.
You might remember from school that a straight line can be described by: y=mx+b. Here, m is the slope of the line and b is the y-intercept. Another way to think about it is that m is how fast the line goes up (or down, if m is negative), and b is where the line “starts” at x=0.
[Vitor] starts out with a great example: home prices (the dependent variable) and area (the independent variable). As you would guess, bigger houses tend to sell for more than smaller houses. But it isn’t an exact formula, because there are a lot of reasons a house might sell for more or less. If you plot it, you don’t get a nice line; you get a cloud of points that sort of group around some imaginary line.
There are mathematical ways to figure out what line you should imagine, but you can often eyeball it, too. The real trick is evaluating the quality of that imaginary line.
To do that, you need an error measure. If you didn’t know better, you’d probably think expressing the error in terms of absolute value would be best. You know, “this is 10 off” or whatever. But, as [Vitor] explains, the standard way to do this is with a squared error term R
2
. Why? Read the post and find out.
For electronics, linear regression has many applications, including interpreting sensor data. You might also use it to generalize a batch of unknown components, for example. Think of a batch of transistors with different Beta values at different frequencies. A linear regression will help you predict the Beta and the error term will tell you if it is worth using the prediction or not. Or, maybe you just want to make the
perfect cup of coffee
. | 7 | 3 | [
{
"comment_id": "8125926",
"author": "shinsukke",
"timestamp": "2025-05-09T09:53:48",
"content": "Knowledge of regression, curve fitting and statistics is immensely helpful for engineers and software folk. Spend a few afternoons just exploring these fields and you will gain amazing tools to do whate... | 1,760,371,553.15694 | ||
https://hackaday.com/2025/05/06/supercon-2024-a-hackers-guide-to-analog-design-in-a-digital-world/ | Supercon 2024: A Hacker’s Guide To Analog Design In A Digital World | Navarre Bartz | [
"cons",
"Hackaday Columns",
"Slider"
] | [
"2024 Hackaday Superconference",
"analog",
"analog design",
"analog electronics"
] | We often think of analog computing as a relic of the past, room-sized monstrosities filled with vacuum tubes doing their best to calculate Monte Carlo simulations or orbital velocities. Analog isn’t as dead as it might seem though, and analog mix signal design engineer [Nanik Adnani] gave us a
crash course on analog circuits at Supercon 2024
.
For those of us less familiar with analog circuits, [Adnani] helpfully offered a definition of analog circuit design as “the design of electronics that create or manipulate continuously variable signals.” It turns out, that even our nice, clean digital signals are actually more analog by the time they interact with the real world. This comes down to various factors like substrate losses, conductors, impedance, and even capacitance. Given the difference in scale between a logic gate and the actual pins the signal comes out of from an integrated circuit, it becomes clear that the amount of current the pin can handle versus the logic gate inside the chip is quite different. In order to bridge the gap, chips use a physical interface, or PHY, which happens to be an analog interface which allows the logic on the chip to communicate off the chip.
[Adnani] explained how every digital protocol in common usage requires some degree of analog circuits including LoRa, USB,
CAN
, etc. Most chips handling these protocols have a separate analog team designing the analog circuit which requires slightly different metal layer design, so while determining the exact function of an analog circuit can be difficult to determine from an X-ray of the chip, finding where they are compared to the digital components is quite simple.
Like with most things we hackers delve into, the best way to learn is by doing after picking up a few basics, and [Adnani] reiterates this throughout his talk. One of the more unexpected examples was his grandmother’s tricked-out walker. It has RGB lighting, a water gun, and a car horn. The car horn required a PHY to step things up from the 40 mA from the microcontroller to the 8 A required to drive the horn.
Some other examples from the talk are this PHY for
storing data on a cassette
by [Zack Nelson], a guitar pedal [Adnani] designed himself for tape out, and
analog bird circuits by [Kelly Heaton].
Analog still has a well-known place in music for various components as well.
The last piece of course, is how do you learn analog circuits when everyone around you lives in the digital realm? [Adnani] recommends starting by hitting the books as internet posts can often be a game of telephone, and getting the values wrong on capacitors or the like is a lot more problematic in an analog circuit. Some of his suggestions are as follows (
~13 min into the video
):
Design of Analog CMOS Circuits
– start here
Sedra and Smith
– if you like math
The Art of Electronics
– board level design
CMOS Circuit Design, Layout, and Simulation
– trying to tapeout a chip
Analog Integrated Circuit Design
– advanced concepts
[Adnani] says, “I had one professor tell me that all you really need is the first four or five chapters of
Design of Analog CMOS Integrated Circuits
by Behzad Rezavi and then you can start building things.” If videos work better for you better, then [Adnani] recommends checking out [
Moritz Klein
], [
Carsten Wulff
], and [
Ali Hajimiri
] who all have robust offerings on the subject.
At the end of the day, you won’t really learn it until you try to build something, so get a box of components and start tinkering. Simulation can also be beneficial, so [Adnani] recommends trying out your circuits in LTspice for discrete simulations and Ngspice if you want to tape out. While taping out a design for a few hundred bucks seems pricey, it’s a lot cheaper than a university course in many regions of the world. [Adnani] ends with an exhortation that if a humble undergraduate can do analog work, then any hacker can too, so maybe give it a whirl on your next project! | 9 | 4 | [
{
"comment_id": "8125070",
"author": "jawnhenry",
"timestamp": "2025-05-06T18:01:19",
"content": "“… if a humble undergraduate can do analog work, then any hacker can too…”This statement is what is commonly known as anon sequitur.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,371,553.250511 | ||
https://hackaday.com/2025/05/06/ai-brings-play-by-play-commentary-to-pong/ | AI Brings Play-by-Play Commentary To Pong | Al Williams | [
"Artificial Intelligence",
"Games"
] | [
"ai",
"LLM",
"pong"
] | While most of us won’t ever play Wimbledon, we can play Pong. But it isn’t the same without the thrill of the sportscaster’s commentary during the game. Thanks to [Parth Parikh] and an LLM, you
can now watch Pong matches with commentary during the game
. You can see the very cool result in the video below — the game itself starts around the 2:50 mark. Sadly, you don’t get to play. It seems like it wouldn’t be that hard to wire yourself in with a little programming.
The game features multiple AI players and two announcers. There are 15 years of tournaments, including four majors, for a total of 60 events. In the 16th year, the two top players face off in the World Championship Final.
There are several interesting techniques here. For one, each action is logged as an event that generates metrics and is prioritized. If an important game event occurs, commentary pauses to announce that event and then picks back up where it left off.
We really want to see a one- or two-player human version of this. Please
tell us
if you take on that challenge. Even if you don’t write it, maybe the AI
can write it for you
. | 6 | 2 | [
{
"comment_id": "8125031",
"author": "threeve",
"timestamp": "2025-05-06T15:54:38",
"content": "Is it really commentary if it’s 90% filler?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125034",
"author": "purplepeopleated",
"timestamp": "2... | 1,760,371,553.200147 | ||
https://hackaday.com/2025/05/06/optical-contact-bonding-where-the-macro-meets-the-molecular/ | Optical Contact Bonding: Where The Macro Meets The Molecular | Maya Posch | [
"Featured",
"Interest",
"Original Art",
"Science",
"Slider"
] | [
"optical contact binding"
] | If you take two objects with fairly smooth surfaces, and put these together, you would not expect them to stick together. At least not without a liberal amount of adhesive, water or some other substance to facilitate a temporary or more permanent bond. This assumption gets tossed out of the window when it comes to optical contact bonding, which is a process whereby two surfaces are joined together without glue.
The fascinating aspect of this process is that it uses the intermolecular forces in each surface, which normally don’t play a major role, due to the relatively rough surfaces. Before intermolecular forces like Van der Waals forces and hydrogen bonds become relevant, the two surfaces should not have imperfections or contaminants on the order of more than a few nanometers. Assuming that this is the case, both surfaces will bond together in a way that is permanent enough that breaking it is likely to cause damage.
Although more labor-intensive than using adhesives, the advantages are massive when considering that it creates an effectively uninterrupted optical interface. This makes it a perfect choice for especially high-precision optics, but with absolutely zero room for error.
Intermolecular Forces
Thirty-six gauges wrung together and held horizontally. (Credit:
Goodrich & Stanley
, 1907)
As creatures of the macro world, we are largely only aware of the macro effects of the various forces at play around us. We mostly understand gravity, and how the friction of our hand against a glass prevents it from sliding out of our hand before shattering into many pieces on the floor. Yet add some water on the skin of our hands, and suddenly there’s not enough friction, leading to unfortunate glass slippage, or a lid on a jar of pickles that stubbornly refuses to open because we cannot generate enough friction until we manage to dry our hands sufficiently.
Many of these macro-level interactions are the result of molecular-level interactions, which range from the glass staying in one piece instead of drifting off as a cloud of atoms, to the system property that we refer to as ‘
friction
‘, which itself is also subdivided into static stiction and dynamic friction. The system of friction can be considered to be analogous to contact binding when we consider two plates with one placed on top of the other. If we proceed to change the angle of these stacked plates, at some point the top plate will slide off the bottom plate. This is the point where the binding forces can no longer compensate for the gravitational pull, with material type and surface finish affecting the final angle.
An interesting example of how much surface smoothness matters can be found in
gauge blocks
. These are precision ground and lapped blocks of metal or ceramic which match a specific thickness. Used for mainly calibration purposes, they posses the fascinating property due to their smooth surfaces that you can make multiple of them adhere together in a near-permanent manner in what is called
wringing
. This way you can combine multiple lengths to create a single gauge block with sub-millimeter accuracy.
Enabling all this are
intermolecular forces
, in particular the Van der Waals forces, including dipole-dipole electrostatic interactions. These do not rely on chemical or similar properties as they depend only on aspects like the mutual repulsion between the electron clouds of the atoms that make up the materials involved. Although these forces are very weak and drop off rapidly with distance, they are generally independent of aspects like temperature.
Hydrogen bonds can also occur if present, with each type of force having its own set of characteristics in terms of strength and effective distance.
Make It Smooth
Surface roughnesses of a SiO2 wafer (left, ≈1.01 nm RMS) and an ULE wafer (right, ≈1.03 nm RMS) (Credit: Kalkowski et al., 2011)
One does not simply polish a surface to a nanometer-perfect sheen, though as computer cooling enthusiasts and kin are aware, you can get pretty far with a smooth surface and various grits of sandpaper all the way up to ridiculously high levels. Giving enough effort and time, you can match the surface finish of something like gauge blocks and shave off another degree or two on that CPU at load.
Achieving even smoother surfaces is essentially taking this to the extreme, though it can be done without 40,000 grit sandpaper as well. The easiest way is probably found in glass and optics production, the latter of which has benefited immensely from the semiconductor industry. A good demonstration of this can be found in a
2011 paper
(
full PDF
) by Fraunhofer researchers G. Kalkowski et al. as published in
Optical Manufacturing and Testing
.
They describe the use of optical contact bonding in the context of glass-glass for optical and precision engineering, specifically low-expansion fused silica (SiO
2
) and ultra-low expansion materials. There is significant overlap between semiconductor wafers and the wafers used here, with the same nanometer level precision, <1 nm RMS surface roughness, a given. Before joining, the surfaces are extensively cleaned of any contaminants in a vacuum environment.
Worse Than Superglue
Once the surfaces are prepared, there comes the tricky part of making both sides join together. Unlike with the gauge blocks, these super smooth surfaces will not come apart again without a fight, and there’s no opportunity to shimmy them around to get that perfect fit like when using adhesive. With the demonstrated method by Kalkowski et al., the wafers were joined followed by heating to 250 ℃ to create permanent Si-O-Si bonds between the two surfaces. In addition bonding pressure was applied for two hours at 2 MPa using either N
2
or O
2
gas.
This also shows another aspect of optical contact binding: although it’s not technically permanent, the bond is still just using intermolecular forces, and, as shown in this study, can be pried apart with a razorblade and some effort. By heating and applying pressure, the two surfaces can be annealed, forming molecular bonds and effectively turning the two parts into one.
Of course, there are many more considerations, such as the low-expansion materials used in the referenced study. If both sides use too dissimilar materials, the bond will be significantly more tenuous than if the materials with the same expansion properties are used. It’s also possible to use chemically activated direct bonding with a chemical activation process, all of which relies on the used materials.
In summary, optical contact bonding is a very useful technique, though you may want to have a well-equipped home lab if you want to give it a spin yourself. | 19 | 12 | [
{
"comment_id": "8125041",
"author": "Ostracus",
"timestamp": "2025-05-06T16:20:50",
"content": "“Wonder-bond powers, activate”!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125247",
"author": "Tinothy X",
"timestamp": "2025-05-07T05:15:24... | 1,760,371,553.376118 | ||
https://hackaday.com/2025/05/06/improving-flying-drones-by-mimicking-flying-squirrels/ | Improving Flying Drones By Mimicking Flying Squirrels | Maya Posch | [
"drone hacks"
] | [
"quadcopter",
"squirrel"
] | With the ability to independently adjust the thrust of each of their four motors, quadcopters are exceptionally agile compared to more traditional aircraft. But in an effort to create an even more maneuverable drone platform, a group of South Korean researchers have studied
adding flying squirrel tech to quadcopters
. Combined with machine learning, this is said to significantly increase the prototype’s agility in an obstacle course.
Flying squirrels (tribe
Pteromyini
)) have large skin flaps (patagium) between their wrists and ankles which they use to control their flight when they glide from tree to tree, along with their fluffy squirrel tail. With flights covering up to 90 meters, they also manage to use said tail and patagium to air brake, which prevents them from smacking with bone jarring velocities into a tree trunk.
By taking these principles and adding a similar mechanism to a quadcopter for extending a patagium-like membrane between its rotors, the researchers could develop a new controller (thrust-wing coordination control, TWCC), which manages the extending of the membranes in coordination with thrust from the brushless motors. Rather than relying on trial-and-error to develop the controller algorithms, the researchers trained a recurrent neural network (RNN) which was pre-trained prior to first flights using simulation data followed by supervised learning to refine the model.
During experiments with obstacle avoidance on a test-track, the RNN-based controller worked quite well compared to a regular quadcopter. A disadvantage is of course that the range of these flying squirrel drones is less due to the extra weight and drag, but if one were to make flying drones that will perch on surfaces between dizzying feats of agility in the air, this type of drone tech might just be the ticket. | 12 | 6 | [
{
"comment_id": "8124962",
"author": "Jouni",
"timestamp": "2025-05-06T11:17:53",
"content": "Did they optimize the flying parameters of non-squirrel version too?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8124977",
"author": "Shara",
"ti... | 1,760,371,553.424197 | ||
https://hackaday.com/2025/05/06/hardware-built-for-executing-python-not-pythons/ | Hardware Built For Executing Python (Not Pythons) | Lewin Day | [
"hardware",
"Software Development"
] | [
"determinism",
"programming",
"python",
"pyxl",
"speed"
] | Lots of microcontrollers will accept Python these days, with CircuitPython and MicroPython becoming ever more popular in recent years. However, there’s now a new player in town. Enter PyXL, a project to
run Python directly in hardware for maximum speed
.
What’s the deal with PyXL? “It’s actual Python executed in silicon,” notes the project site. “A custom toolchain compiles a .py file into CPython ByteCode, translates it to a custom assembly, and produces a binary that runs on a pipelined processor built from scratch.” Currently, there isn’t a hard silicon version of PyXL — no surprise given what it costs to make a chip from scratch. For now, it exists as logic running on a Zynq-7000 FPGA on a Arty-Z7-20 devboard. There’s an ARM CPU helping out with setup and memory tasks for now, but the Python code is executed entirely in dedicated hardware.
The headline feature of PyXL is speed. A comparison video demonstrates this with a measurement of GPIO latency. In this test, the PyXL runs at 100 MHz, achieving a round-trip latency of 480 nanoseconds. This is compared to MicroPython running on a PyBoard at 168 MHz, which achieves a much slower 15,000 nanoseconds by comparison. The project site claims PyXL can be 30x faster than MicroPython based on this result, or 50x faster when normalized for the clock speed differences.
Python has never been the most real-time of languages, but efforts like this attempt to push it this way. The aim is that it may finally be possible to write performance-critical code in Python from the outset.
We’ve taken a look at Python in the embedded world before, too, albeit in very different contexts. | 42 | 12 | [
{
"comment_id": "8124935",
"author": "bateske",
"timestamp": "2025-05-06T08:29:41",
"content": "Wow all that work and still several times slower than C",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8124937",
"author": "Richard",
"timestamp":... | 1,760,371,553.843415 | ||
https://hackaday.com/2025/05/05/nebula-mouse-the-6-dof-you-build-yourself/ | Nebula Mouse: The 6-DOF You Build Yourself | Heidi Ulrich | [
"Peripherals Hacks"
] | [
"6-DOF",
"axis",
"mouse",
"nebula",
"nRF52840",
"seeed xiao",
"space mouse"
] | Let’s say your CAD workflow is starving for spatial awareness. Your fingers yearn to push, twist, and orbit – not just click.
Enter the Nebula Mouse
. A 6-DOF DIY marvel, blending 3D printing, magnets, and microcontroller wizardry into a handheld input device that emulates the revered 3DConnexion SpaceMouse – at a hacker price. It’s wireless, RGB-lit, powered by a chunky 1500 mAh cell, and fully configurable through standard apps. The catch? You print and build it yourself, with a little help of [DoTheDIY]’s design files.
This isn’t some half-baked enclosure on Thingiverse. The Nebula’s internals are crafted with the kind of precision that makes you file plastic for hours just to fit weights correctly. Hall effect sensors track real-world movement in all axes; a Seeed Xiao nRF52840 handles Bluetooth duty. It’s hefty (280 g), intentional, and smartly designed: auto-wake, USB-C, even a diffused LED bezel for night-time geek cred. Just beware that screw lengths matter. Misplace a 20 mm and you’ll hear the soft crack of PCB grief. No open firmware either – you’ll get compiled code only, unlocked per build
via Discord
.
In short: it’s not open source, but it is deeply open-ended. If your fingers itch after having seen
the SpaceMouse teardown
of last month, this might be what you’re looking for. | 31 | 12 | [
{
"comment_id": "8124905",
"author": "jpa",
"timestamp": "2025-05-06T05:54:16",
"content": "Open source alternatives:https://hackaday.io/project/187172-os3m-mousehttps://www.instructables.com/Space-Mushroom-Full-6-DOFs-Controller-for-CAD-Appl/",
"parent_id": null,
"depth": 1,
"replies": ... | 1,760,371,553.571448 | ||
https://hackaday.com/2025/05/05/3d-print-your-own-injection-molds-ejector-pins-and-all/ | 3D Print Your Own Injection Molds, Ejector Pins And All | Lewin Day | [
"3d Printer hacks"
] | [
"3d printing",
"injection mold",
"injection molding"
] | 3D printing is all well and good for prototyping, and it can even produce useful parts. If you want real strenght in plastics, though, or to produce a LOT of parts, you probably want to step up to injection molding. As it turns out, 3D printing can help in that regard, with injection molding company [APSX] has given us a look at how it printed
injection molds for its APSX-PIM machine.
The concept is simple enough—additive manufacturing is great for producing parts with complex geometries, and injection molds fit very much under that banner. To demonstrate, [APSX] shows us a simple injection mold that it printed with a Formlabs Form3+ using Rigid 10K resin. The mold has good surface finish, which is crucial for injection molding nice parts. It’s also fitted with ejection pins for easy part removal after each shot of injection molded plastic. While it’s not able to hold up like a traditional metal injection mold, it’s better than you might think. [APSX] claims it got 500 automatic injection cycles out of the mold while producing real functional parts. The mold was used with the APSX-PIM injection molding machine squirting polypropylene at a cycle time of 65 seconds, producing a round part that appears to be some kind of lid or gear.
This looks great, but it’s worth noting it’s still not cheap to get into this sort of thing. On top of purchasing a Formlabs Form3+, you’ll also need the APSX-PIM V3, which currently retails
for $13,500 or so.
Still, if you regularly need to make 500 of something, this could be very desirable. You could get your parts quicker and stronger compared to running a farm of many 3D printers turning out the same parts.
We’ve seen similar projects along these lines before
. The fact is that injections molds are complicated geometry to machine, so being able to 3D print them is highly desirable. Great minds and all that. Video after the break. | 20 | 8 | [
{
"comment_id": "8124882",
"author": "Clyde",
"timestamp": "2025-05-06T03:26:45",
"content": "The random full screen flashing in the video was rather unpleasant. Would have been nice to see the design process.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8... | 1,760,371,553.631114 | ||
https://hackaday.com/2025/05/07/magic-on-your-desk-via-maglev-toy/ | Magic On Your Desk Via MagLev Toy | Tyler August | [
"classic hacks"
] | [
"levitation",
"Magnetic levitation",
"magnets",
"stm32"
] | Magnets aren’t magic, but sometimes you can do things with them to fool the uninitiated — like levitating. [Jonathan Lock] does that with
his new maglev desk toy
, that looks like at least a level 2 enchantment.
This levitator is USB-powered, and typically draws 1 W to 3 W to levitate masses between 10 g and 500 g. The base can provide 3 V to 5 V inductive power to the levitator to the tune of 10 mA to 50 mA, which is enough for some interesting possibilities, starting with the lights and motors [Jonathan] has tried.
In construction it is much like the commercial units you’ve seen: four permanent magnets that repel another magnet in the levitator. Since such an arrangement is about as stable as balancing a basketball on a piece of spaghetti, the permanent magnets are wrapped in control coils that pull the levitator back to the center on a 1 kHz loop. This is accomplished by way of a hall sensor and an STM32 microcontroller running a PID loop. The custom PCB also has an onboard ESP32, but it’s used as a very overpowered USB/UART converter to talk to the STM32 for tuning in the current firmware.
If you think one of these would be nice to have on your desk, check it out on [Jonathan]’s GitLab. It’s all there, from a detailed build guide (with easy-to-follow animated GIF instructions) to CAD files and firmware. Kudos to [Jonathan] for the quality write-up; sometimes documenting is the hardest part of a project, and it’s worth acknowledging that as well as the technical aspects.
We’ve written about magnetic levitation before, but
it doesn’t always go as well as this project
. Other times,
it very much does.
There are also other ways to accomplish the same feat,
some of which can lift quite a bit more
. | 9 | 6 | [
{
"comment_id": "8125310",
"author": "Jonathan Lock",
"timestamp": "2025-05-07T11:11:19",
"content": "Thanks for the write-up Tyler! It’ll be fun to see if anyone either builds one of their own or extends on this, e.g. doing something useful with the ESP32 or something more interesting than just lig... | 1,760,371,553.682452 | ||
https://hackaday.com/2025/05/07/tracking-the-sun-nah/ | Tracking The Sun? Nah! | Al Williams | [
"Solar Hacks"
] | [
"east west array",
"solar power",
"solar tracker"
] | If you want solar power, you usually have to make a choice. You can put a solar panel in a fixed location and accept that it will only put out the maximum when the sun is properly positioned. Or, you can make the panels move to track the sun.
While this isn’t difficult, it does add cost and complexity, plus mechanical systems usually need more maintenance. According to [Xavier Derdenback], now that solar panels are cheaper than ever, it is
a waste of money to make a tracking array
. Instead, you can build a system that looks to the east and the west. The math says it is more cost effective.
The idea is simple. If you have panels facing each direction, then one side will do better than the other side in the morning. The post points out that a tracking setup, of course, will produce more power. That’s not the argument. However, for a given power output, the east-west solution has lower installation costs and uses less land.
Letting the post speak for itself:
East-West arrays are simple. They consist of parallel strings of PV modules that are oriented in opposing directions, one facing East and the other West. The current of the whole array is the summation of these string currents, effectively letting East-West arrays capture sunlight from dawn till dusk, similar to a tracked array.
So what do you think? Are solar trackers old hat? If you want one, they
don’t have to be very complex
. But still easier to just double your panels. | 43 | 15 | [
{
"comment_id": "8125285",
"author": "paulvdh",
"timestamp": "2025-05-07T08:17:54",
"content": "Tracking systems for solar panels have always been a very niche phenomena because of this. Even 20 years ago when solar panels were still expensive, tracking systems were rare. And it’s not only installa... | 1,760,371,553.761875 | ||
https://hackaday.com/2025/05/06/adorable-robot-steals-the-show/ | Adorable Robot Steals The Show | Tyler August | [
"Tech Hacks"
] | [
"arduino",
"movie prop",
"remote control"
] | An ongoing refrain with modern movies is “Why is all of this CG?”– sometimes, it seems like practical effects are simultaneously a dying art, while at the same time modern technology lets them rise to new hights. [Davis Dewitt] proves that second statement with his
RC movie star “robot” for an upcoming feature film
.
The video takes us through the design process, including what it’s like to work with studio concept artists. As for the robot, it’s controlled by an Arduino Nano, lots of servos, and a COTS airplane R/C controller, all powered by li-po batteries. This is inside an artfully weathered and painted 3D printed body. Apparently weathering is important to make the character look like a well-loved ‘good guy’. (Shiny is evil, who knew?) Hats off to [Davis] for replicating that weathering for an identical ‘stunt double’.
Check out the video below for all the deets, or you can watch to see if
“The Lightning Code” is coming to a theater near you
. If you’re into films, this isn’t the first hack [Davis]
has made for the silver screen
. If you prefer “real” hacks to props, his
Soviet-Era Nixie clock would look great on any desk
. Thanks to [Davis] for letting us know about this project via
the tips line. | 12 | 9 | [
{
"comment_id": "8125294",
"author": "IanS",
"timestamp": "2025-05-07T09:00:23",
"content": "“Lightening” means getting less dark. “Lightning” is a an electrical discharge in the atmosphere.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125323",
"... | 1,760,371,554.009348 | ||
https://hackaday.com/2025/05/06/diy-penicillin/ | DIY Penicillin | Al Williams | [
"Science"
] | [
"antibiotic",
"bioreactor"
] | We don’t often consider using do-it-yourself projects as a hedge against the apocalypse. But [The Thought Emporium] thinks we should
know how to make penicillin
just in case. We aren’t so sure, but we do think it is a cool science experiment, and you can learn how to replicate it in the video below.
If you want to skip the history lesson, you need to fast-forward to about the six-minute mark. According to the video, we are surrounded by mold that can create anti-bacterial compounds. However, in this case, he starts with a special strain of mold made to produce lots of antibiotics.
You may not have all the gear he uses, including a bioreactor to generate liters of mold. Even with a lot of mold, the yield of penicillin is relatively low. Since Purina doesn’t make mold chow, you’ll have to create your own food for the mold colony.
All the work he did wound up producing 125 milligrams of drug. Obviously, if you are going to save the post-apocalyptic world, you are going to need to scale that process up.
If you are the sole survivor, maybe your
AI companion can help out
. | 16 | 6 | [
{
"comment_id": "8125214",
"author": "David",
"timestamp": "2025-05-07T02:11:22",
"content": "Only until the apocalypse. As the song says, “When the states and the cities fall … Black power and alcohol [and penicillin].”",
"parent_id": null,
"depth": 1,
"replies": [
{
"com... | 1,760,371,553.959054 | ||
https://hackaday.com/2025/05/06/five-oddest-op-amp-applications/ | Five Oddest Op Amp Applications | Al Williams | [
"Parts"
] | [
"analog",
"op amps",
"parts"
] | You think of op amps as amplifiers because, no kidding, it is right in the name. But just like some people say, “you could do that with a 555,” [Doctor Volt] might say, “
you can do that with an op amp
.” In a recent video, you can see below, he looks at simulations and breadboards for five applications that aren’t traditional amplifiers.
Of course, you can split hairs. A comparator is sort of an amplifier with some very specific parameters, but it isn’t an amplifier in the classic sense.
In addition to comparators, there’s a flip flop, a few oscillators, and a PWM audio over optical transmitter and receiver. If you want to test your understanding of op amps, you can try to analyze the different circuits to see if you can explain how they work.
Op amps are amazing for analog design since you don’t have to build up high-quality amplifier blocks from discrete devices. Even the worst op amp you can buy is probably better than something you have the patience to design in a few minutes with a FET or a bipolar device. Fair to say that we do enjoy these
oddball op amp circuits
. | 25 | 10 | [
{
"comment_id": "8125216",
"author": "AZdave",
"timestamp": "2025-05-07T02:16:34",
"content": "A clue to why op amps aren’t simply a traditional amplifier (and never have been) can be found in their name, which is “operational amplifier”.",
"parent_id": null,
"depth": 1,
"replies": [
... | 1,760,371,553.909729 | ||
https://hackaday.com/2025/05/06/a-new-smarter-universal-remote/ | A New, Smarter Universal Remote | Matthew Carlson | [
"home hacks",
"Wireless Hacks"
] | [
"ESP32",
"homeassistant",
"remote",
"smarthome"
] | The remote for [Dillan Stock]’s TV broke,
so he built a remote
. Not just as a replacement but as something new. For some of us, there was a glorious time in the early 2000s when a smart remote was needed and there were options you could buy off the shelf. Just one handy button next to the screen had a macro programmed that would turn on the receiver, DVD player, and TV, and then configure it with the right inputs. However, the march of technological convenience has continued and nowadays soundbars turn on just in time and the TV auto switches the input. Many devices are (for better or worse) connected to WiFi, allowing all sorts of automation.
[Dillan] was lucky enough that his devices were connected to his home assistant setup. So this remote is an ESP32 running ESPHome. These automations could be triggered by your phone or via voice assistant. What is more interesting is watching [Dillan] go through the design process. Deciding what buttons there should be, where they should be placed, and how the case would snap together takes real effort. The design uses all through-hole components except for the ESP32 which is a module.
This isn’t the first thing [Dillan] has made with an ESP32, as he
previously revamped a non-standard smart lamp
with the versatile dev board. The
3d printable files
for the remote are free available. Video after the break. | 21 | 6 | [
{
"comment_id": "8125162",
"author": "Miles",
"timestamp": "2025-05-06T22:36:03",
"content": "I was a big fan of the all-in-one you could buy dirt cheap from Radio Shack or Walmart. Even the ‘blue peanut” from Tivo was one of theirs. There were blank pads on the PCB and a 6-pin programming header ... | 1,760,371,554.066254 | ||
https://hackaday.com/2025/05/06/building-a-diy-chicken-incubator/ | Building A DIY Chicken Incubator | Lewin Day | [
"classic hacks"
] | [
"chicken",
"eggs",
"incubator"
] | If you want to keep eggs warm to hatch, you’ll need an incubator. You could buy one off the shelf, but they’re not so complex — just a nicely-controlled warm box you could easily whip up yourself. As it turns out,
that’s precisely what [RCLifeOn] did.
The incubator is built out of wooden panels screwed together to make a simple box. The frame of the front door is also wood, but it features 3D printed hinges and handles, because that’s the easiest way to make hardware
when you’re a printing wizard like [RCLifeOn].
The box is fitted with controls for humidity and temperature to ensure the best possible conditions for hatching chicken eggs inside. As you might have guessed, a heated bed from a 3D printer was used to control the temperature inside. As for humidity, a sensor tracks the conditions in the box, and triggers an ultrasonic mister to increase the level as necessary. There’s also a little motion introduced via a moving platform run by a motor and some step-down gearing, which apparently aids in the hatching process.
[RCLifeOn] calls it “a machine that creates life,” and that honestly sounds about fair.
We’ve seen similar projects along these lines before, too.
[Thanks to Chris Muncy for the tip!] | 16 | 9 | [
{
"comment_id": "8125081",
"author": "craig",
"timestamp": "2025-05-06T18:50:17",
"content": "Nice tuning in to HaD and seeing hot chicks!",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125467",
"author": "CAROL",
"timestamp": "2025-05-07T22... | 1,760,371,554.115842 | ||
https://hackaday.com/2025/05/07/jellybean-mac-hides-modern-pc/ | Jellybean Mac Hides Modern PC | Tyler August | [
"Retrocomputing"
] | [
"case",
"imac",
"mac",
"pc"
] | The iMac G3 is an absolute icon of industrial design, as (or perhaps more) era-defining than the Mac Classic before it. In the modern day, if your old iMac even boots, well, you can’t do much with it. [Rick Norcross] got a hold of a dead (hopefully irreparable) specimen, and
stuffed a modern PC inside of it
.
From the outside, it’s suprizingly hard to tell. Of course the CRT had to go, replaced with a 15″ ELO panel that fits well after being de-bezeled. (If its resolution is only 1024 x 768, well, it’s also only 15″, and that pixel density matches the case.) An M-ATX motherboard squeezes right in, above a modular PSU. Cooling comes from a 140 mm case fan placed under the original handle. Of course you can’t have an old Mac without a startup chime, and [Rick] obliges by including an Adafruit FX board wired to the internal speakers, set to chime on power-up while the PC components are booting.
These sorts of mods have proven controversial in the past– certainly there’s good reason to want to
preserve aging hardware
–but perhaps with this generation of iMac it won’t raise the same ire as
when someone guts a Mac Classic.
We’ve seen the same treatment
given to a G4 iMac
, but somehow the lamp doesn’t quite have the same place in our hearts as the redoubtable jellybean. | 19 | 9 | [
{
"comment_id": "8125524",
"author": "drypaperhammerbro",
"timestamp": "2025-05-08T05:03:49",
"content": "Neat case, shame the CRT was thrown out",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125547",
"author": "Joshua",
"timestamp": "2025-... | 1,760,371,554.320508 | ||
https://hackaday.com/2025/05/07/superconductivity-news-what-makes-floquet-majorana-fermions-special-for-quantum-computing/ | Superconductivity News: What Makes Floquet Majorana Fermions Special For Quantum Computing? | John Elliot V | [
"Science"
] | [
"Floquet Majorana fermions",
"Josephson effect",
"quantum computing",
"superconductivity",
"topological superconductors"
] | Researchers from the USA and India have proposed that
Floquet Majorana fermions may improve quantum computing by controlling superconducting currents
, potentially reducing errors and increasing stability.
In
a study
published in Physical Review Letters that was co-authored by [Babak Seradjeh], a Professor of Physics at Indiana University Bloomington, and theoretical physicists [Rekha Kumari] and [Arijit Kundu], from the Indian Institute of Technology Kanpur, the scientists validate their theory using numerical simulations.
In the absence of room-temperature superconductors —
the Holy Grail of superconductivity
, everybody put your thinking caps on! — the low temperatures required lead to expense (for cooling) and errors (due to decoherence) which need to be managed. Using the techniques proposed by the study, quantum information may be modeled non-locally and be spread out spatially in a material, making it more stable and less error prone, immune to local noise and fluctuations.
Majorana fermions are named after Italian physicist [Ettore Majorana] who proposed them in 1937. Unlike most particles, Majorana fermions are their own antiparticles. In the year 2000 mathematical physicist [Alexei Kitaev] realized Majorana fermions can exist not only as elementary particles but also as quantum excitations in certain materials known as topological superconductors. Topological superconductors differ from regular superconductors in that they have unique, stable quantum states on their surface or edges that are protected by the material’s underlying topology.
Superconductivity is such an interesting phenomenon, where electrical resistance all but vanishes in certain materials when they are very cold. Usually to induce a current in a material you apply a voltage, or potential difference, in order to create the electrical pressure that results in the current. But in a superconductor currents can flow in the absence of an applied voltage. This is because of a peculiar quantum tunneling process known as the “Josephson effect”. It is hoped that by tuning the Josephson current using a superconductor’s “chemical potential” that we discover a new level of control over quantum materials.
Ettore Majorana picture: Mondadori Collection,
Public domain
. | 13 | 5 | [
{
"comment_id": "8125520",
"author": "Gravis",
"timestamp": "2025-05-08T03:54:06",
"content": "Numerical simulations are of course only valid if our equations describing reality are an accurate representation. Obviously it’s a reasonable hypothesis that is worth pursuing but it’s impossible to accou... | 1,760,371,554.254319 | ||
https://hackaday.com/2025/05/07/wireless-usb-autopsy/ | Wireless USB Autopsy | Al Williams | [
"Retrocomputing"
] | [
"CF-USB",
"CW-USB",
"usb",
"Wireless USB"
] | It might seem strange to people like us, but normal people hate wires. Really hate wires. A lot. So it makes sense that with so many wireless technologies, there should be a way to do USB over wireless. There is, but it really hasn’t caught on outside of a few small pockets. [Cameron Kaiser] wants to
share why he thinks the technology never went anywhere
.
Wireless USB makes sense. We have high-speed wireless networking. Bluetooth doesn’t handle that kind of speed, but forms a workable wireless network. In the background, of course, would be competing standards.
Texas Instruments and Intel wanted to use multiband orthogonal frequency-division multiplexing (MB-OFDM) to carry data using a large number of subcarriers. Motorola (later Freescale), HP, and others were backing the competing direct sequence ultra-wideband or DS-UWB. Attempts to come up with a common system degenerated.
This led to two systems W-USB (later CF-USB) and CW-USB. CF-USB looked just like regular USB to the computer and software. It was essentially a hub that had wireless connections. CW-USB, on the other hand, had cool special features, but required changes at the driver and operating system level.
Check out the post to see a bewildering array of orphaned and incompatible products that just never caught on. As [Cameron] points out, WiFi and Bluetooth have improved to the point that these devices are now largely obsolete.
Of course, you can transport
USB over WiFi
, and maybe that’s the best answer, today. That is, if you really hate wires. | 22 | 7 | [
{
"comment_id": "8125500",
"author": "D",
"timestamp": "2025-05-08T01:35:42",
"content": "As a hacker, I love cables for myself, but everyone else in my apartment building should feel free to use the RF spectrum if they want.",
"parent_id": null,
"depth": 1,
"replies": [
{
... | 1,760,371,554.682979 | ||
https://hackaday.com/2025/05/07/liquid-silicone-3d-printing-is-no-joke/ | Liquid Silicone 3D Printing Is No Joke | Tyler August | [
"3d Printer hacks"
] | [
"3d printing",
"liquid printing",
"silicone"
] | They might call it Levity, but there’s nothing funny about Rapid Liquid Print’s new silicone 3D printer. It has to be seen to be believed, and luckily [3D Printing Nerd] gives us lots of
beauty shots in this short video
, embedded below.
Smooth, and
fast
. This bladder took 51 minutes according to the RLP website.
Printing a liquid, even a somewhat-viscous one like platinum-cure silicone, presents certain obvious challenges. The Levity solves them with buoyancy: the prints are deposited not onto a bed, but into a gel, meaning they are fully supported as the silicone cures. The fact that the liquid doesn’t cure instantly has a side benefit: the layers bleed into one another, which means this technique should (in theory) be stronger in all directions than FDM printing. We have no data to back that up, but what you can see for yourself that the layer-blending creates a very smooth appearance in the finished prints.
If you watch the video, it really looks like magic, the way prints appear in the gel. The gel is apparently a commercially-available hydrogel, which is good since the build volume looks to need ̶a̶b̶o̶u̶t̶ ̶5̶0̶0̶ ̶L̶ at least 125 L of the stuff. The two-part silicone is also industry-standard and off-the-shelf, though no doubt the exact ratios and are tweaked for purpose. There’s no magic, just a really neat technology.
If you want one, you can sign up for the waiting list at
Rapid Liquid Print’s website,
but be prepared to wait; units ship next year, and there’s already a list.
Alternatively, since there is no magic here, we’d love to see someone take it on themselves, the way once equally exotic
SLS printers have entered the DIY world
. There was a time when resin printers were new and exotic and
hobbyists had to roll their own, too
. None of this is to say we don’t respect the dickens out of the Rapid Liquid Print team and their achievement–it’s just that imitation is the sincerest form of flattery. | 45 | 14 | [
{
"comment_id": "8125444",
"author": "KR3ATOR",
"timestamp": "2025-05-07T20:14:52",
"content": "Cool tech and nice write-up!I suppose you mean it is more isotropic than FDM (instead of less)?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125446",
"... | 1,760,371,554.622706 | ||
https://hackaday.com/2025/05/07/floss-weekly-episode-832-give-yourself-a-medal/ | FLOSS Weekly Episode 832: Give Yourself A Medal | Jonathan Bennett | [
"Hackaday Columns",
"Podcasts",
"Slider"
] | [
"CIRCL",
"FLOSS Weekly",
"Kunai"
] | This week,
Jonathan Bennett
chats with
Alexandre
Dulaunoy
and
Quentin Jérôme
about
Kunai
and CIRCL! How does Kunai help solve Linux security monitoring? Why is eBPF the right place for one of these tools to run? And how is CIRCL helping Luxembourg and the world deal with the modern security landscape? Watch to find out!
https://github.com/kunai-project
https://circl.lu/
https://www.foo.be/
https://euvd.enisa.europa.eu/
Did you know you can watch the live recording of the show right on
our YouTube Channel
? Have someone you’d like us to interview? Let us know, or contact the guest and have them contact us!
Take a look at the schedule here
.
Direct Download
in DRM-free MP3.
If you’d rather read along,
here’s the transcript for this week’s episode
.
Places to follow the FLOSS Weekly Podcast:
Spotify
RSS
Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)
Licensed under
Creative Commons: By Attribution 4.0 License | 0 | 0 | [] | 1,760,371,554.451083 | ||
https://hackaday.com/2025/05/07/germanys-cabinentaxi-the-double-sided-monorail-that-wasnt-meant-to-be/ | Germany’s Cabinentaxi: The Double-Sided Monorail That Wasn’t Meant To Be | Maya Posch | [
"Transportation Hacks"
] | [
"monorail",
"public transportation"
] | The 1970s was a perfect time for alternative modes of transport to be trialed that might replace cars in the wake of the global oil crisis. One of these was the Cabinentaxi, or C-Bahn as it was later called, which was a variation on the standard suspended and monorail concepts.
It was a people mover concept, with ‘pods’ (or cabins) that’d ride either on top of or below the suspended track. It was tested intensively over the course of six years, performed admirably, and completely failed to materialize commercially due to budget crunch times around the world.
Recently [Tim Traveller]
went to the muddy farm field
that once housed the big test track (pictured above), of which nothing remains but the gates and a sign. Despite the fact that few people have heard of Cabinentaxi prior to seeing [Tim]’s video or reading this, there is a big
Wikipedia entry
on it, as well as a
(German language) site
dedicated to the technology.
What made the C-Bahn different from trains and buses were the smaller pods, high throughput capacity and ability to call a pod on demand at any of the stations. This kind of flexibility is what is seen more or less with today’s people moving systems at airports and some cities, except the C-Bahn was classified as a personal rapid transport (PRT), with on-demand pods that could travel between any two stations without stopping or delays. This is something that isn’t seen with public transport today, even if self-driving cars purport to one day do this kind of trick.
Considering that this technology died most due to economical circumstances, we remain hopeful to see its revival one day.
Top image: Cabinentaxi layout as it existed in 1978, with labels by the Tim Traveller YT channel. | 14 | 8 | [
{
"comment_id": "8125382",
"author": "Aaron",
"timestamp": "2025-05-07T16:16:58",
"content": "“Gadgetbahn”. What a great word. Probably because of Disneyland, I have always loved monorails and am just a little heartbroken that they aren’t really practical.This reminds me quite a lot of the Morgantow... | 1,760,371,554.737449 | ||
https://hackaday.com/2025/05/07/big-chemistry-cement-and-concrete/ | Big Chemistry: Cement And Concrete | Dan Maloney | [
"Engineering",
"Featured",
"Interest",
"Original Art",
"Slider"
] | [
"architecture",
"cement",
"Chemistry",
"concrete"
] | Not too long ago, I was searching for ideas for the next installment of
the “Big Chemistry” series
when I found
an article
that discussed the world’s most-produced chemicals. It was an interesting article, right up my alley, and helpfully contained a top-ten list that I could use as a crib sheet for future articles, at least for the ones I hadn’t covered already, like the
Haber-Bosch process for ammonia
.
Number one on the list surprised me, though: sulfuric acid. The article stated that it was far and away the most produced chemical in the world, with 36 million tons produced every year in the United States alone, out of something like 265 million tons a year globally. It’s used in a vast number of industrial processes, and pretty much everywhere you need something cleaned or dissolved or oxidized, you’ll find sulfuric acid.
Staggering numbers, to be sure, but is it really the most produced chemical on Earth? I’d argue not by a long shot, when there’s a chemical that we make 4.4
billion
tons of every year: Portland cement. It might not seem like a chemical in the traditional sense of the word, but once you get a look at what it takes to make the stuff, how finely tuned it can be for specific uses, and how when mixed with sand, gravel, and water it becomes the stuff that holds our world together, you might agree that cement and concrete fit the bill of “Big Chemistry.”
Rock Glue
To kick things off, it might be helpful to define some basic terms. Despite the tendency to use them as synonyms among laypeople, “cement” and “concrete” are entirely different things. Concrete is the finished building material of which cement is only one part, albeit a critical part. Cement is, for lack of a better term, the glue that binds gravel and sand together into a coherent mass, allowing it to be used as a building material.
What did the Romans ever do for us? The concrete dome of the Pantheon is still standing after 2,000 years. Source: Image by
Sean O’Neill
from Flickr via
Monolithic Dome Institute
(CC BY-ND 2.0)
It’s not entirely clear who first discovered that calcium oxide, or lime, mixed with certain silicate materials would form a binder strong enough to stick rocks together, but it certainly goes back into antiquity. The Romans get an outsized but well-deserved portion of the credit thanks to their use of pozzolana, a silicate-rich volcanic ash, to make the concrete that held the aqueducts together and built such amazing structures as the dome of the Pantheon. But the use of cement in one form or another can be traced back at least to ancient Egypt, and probably beyond.
Although there are many kinds of cement, we’ll limit our discussion to Portland cement, mainly because it’s what is almost exclusively manufactured today. (The “Portland” name was a bit of branding by its inventor, Joseph Aspdin, who thought the cured product resembled the famous limestone from the Isle of Portland off the coast of Dorset in the English Channel.)
Portland cement manufacturing begins with harvesting its primary raw material, limestone. Limestone is a sedimentary rock rich in carbonates, especially calcium carbonate (CaCO
3
), which tends to be found in areas once covered by warm, shallow inland seas. Along with the fact that limestone forms between 20% and 25% of all sedimentary rocks on Earth, that makes limestone deposits pretty easy to find and exploit.
Cement production begins with quarrying and crushing vast amounts of limestone. Cement plants are usually built alongside the quarries that produce the limestone or even right within them, to reduce transportation costs. Crushed limestone can be moved around the plant on conveyor belts or using powerful fans to blow the crushed rock through large pipes. Smaller plants might simply move raw materials around using haul trucks and front-end loaders. Along with the other primary ingredient, clay, limestone is stored in large silos located close to the star of the show: the rotary kiln.
Turning and Burning
A rotary kiln is an enormous tube, up to seven meters in diameter and perhaps 80 m long, set on a slight angle from the horizontal by a series of supports along its length. The supports have bearings built into them that allow the whole assembly to turn slowly, hence the name. The kiln is lined with refractory materials to resist the flames of a burner set in the lower end of the tube. Exhaust gases exit the kiln from the upper end through a riser pipe, which directs the hot gas through a series of preheaters that slowly raise the temperature of the entering raw materials, known as rawmix.
The rotary kiln is the centerpiece of Portland cement production. While hard to see in this photo, the body of the kiln tilts slightly down toward the structure on the left, where the burner enters and finished clinker exits. Source: by nordroden, via Adobe Stock (licensed).
Preheating the rawmix drives off any remaining water before it enters the kiln, and begins the decomposition of limestone into lime, or calcium oxide:
The rotation of the kiln along with its slight slope results in a slow migration of rawmix down the length of the kiln and into increasingly hotter regions. Different reactions occur as the temperature increases. At the top of the kiln, the 500 °C heat decomposes the clay into silicate and aluminum oxide. Further down, as the heat reaches the 800 °C range, calcium oxide reacts with silicate to form the calcium silicate mineral known as belite:
Finally, near the bottom of the kiln, belite and calcium oxide react to form another calcium silicate, alite:
It’s worth noting that cement chemists have a specialized nomenclature for alite, belite, and all the other intermediary phases of Portland cement production. It’s a shorthand that looks similar to standard chemical nomenclature, and while we’re sure it makes things easier for them, it’s somewhat infuriating to outsiders. We’ll stick to standard notation here to make things simpler. It’s also important to note that the aluminates that decomposed from the clay are still present in the rawmix. Even though they’re not shown in these reactions, they’re still critical to the proper curing of the cement.
Portland cement clinker. Each ball is just a couple of centimeters in diameter. Source:
مرتضا
, Public domain
The final section of the kiln is the hottest, at 1,500 °C. The extreme heat causes the material to sinter, a physical change that partially melts the particles and adheres them together into small, gray lumps called clinker. When the clinker pellets drop from the bottom of the kiln, they are still incandescently hot. Blasts of air that rapidly bring the clinker down to around 100 °C. The exhaust from the clinker cooler joins the kiln exhaust and helps preheat the incoming rawmix charge, while the cooled clinker is mixed with a small amount of gypsum and ground in a ball mill. The fine gray powder is either bagged or piped into bulk containers for shipment by road, rail, or bulk cargo ship.
The Cure
Most cement is shipped to concrete plants, which tend to be much more widely distributed than cement plants due to the perishable nature of the product they produce. True, both plants rely on nearby deposits of easily accessible rock, but where cement requires limestone, the gravel and sand that go into concrete can come from a wide variety of rock types.
Concrete plants quarry massive amounts of rock, crush it to specifications, and stockpile the material until needed. Orders for concrete are fulfilled by mixing gravel and sand in the proper proportions in a mixer housed in a batch house, which is elevated above the ground to allow space for mixer trucks to drive underneath. The batch house operators mix aggregate, sand, and any other admixtures the customer might require, such as plasticizers, retarders, accelerants, or reinforcers like chopped fiberglass, before adding the prescribed amount of cement from storage silos. Water may or may not be added to the mix at this point. If the distance from the concrete plant to the job site is far enough, it may make sense to load the dry mix into the mixer truck and add the water later. But once the water goes into the mix, the clock starts ticking, because the cement begins to cure.
Cement curing is a complex process involving the calcium silicates (alite and belite) in the cement, as well as the aluminate phases. Overall, the calcium silicates are hydrated by the water into a gel-like substance of calcium oxide and silicate. For alite, the reaction is:
Scanning electron micrograph of cured Portland cement, showing needle-like ettringite and plate-like calcium oxide. Source:
US Department of Transportation
, Public domain
At the same time, the aluminate phases in the cement are being hydrated and interacting with the gypsum, which prevents early setting by forming a mineral known as ettringite. Without the needle-like ettringite crystals, aluminate ions would adsorb onto alite and block it from hydrating, which would quickly reduce the plasticity of the mix. Ideally, the ettringite crystals interlock with the calcium silicate gel, which binds to the surface of the sand and gravel and locks it into a solid.
Depending on which adjuvants were added to the mix, most concretes begin to lose workability within a few hours of rehydration. Initial curing is generally complete within about 24 hours, but the curing process continues long after the material has solidified. Concrete in this state is referred to as “green,” and continues to gain strength over a period of weeks or even months. | 24 | 11 | [
{
"comment_id": "8125379",
"author": "Cheese Whiz",
"timestamp": "2025-05-07T15:58:26",
"content": "On picture #2, is it tilting down to the right or to the left?",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8125383",
"author": "Cheese Whiz",
... | 1,760,371,554.851845 | ||
https://hackaday.com/2025/05/04/a-delay-line-memory-demo-board/ | A Delay Line Memory Demo Board | Lewin Day | [
"LED Hacks",
"Retrocomputing"
] | [
"delay line memory",
"memory"
] | Delay line memory is a technology from yesteryear, but it’s not been entirely forgotten. [P-Lab] has developed
a demo board for delay-line memory
, which shows how it worked in a very obvious way with lots of visual aids.
If you’re unfamiliar with the technology, it’s a form of memory that was used in classic computers like the Univac-I and the Olivetti Programma 101. It’s a sequential-access technology, where data is stored as pulses in some kind of medium, and read out in order. Different forms of the technology exist, such as using acoustic pulses in mercury or torsional waves passing through coiled nickel wire.
In this case, [P-Lab] built a solid state delay line using TTL ICs, capable of storing a full 64 bits of information and running at speeds of up to 150 kHz. It also features a write-queuing system to ensure bits are written at the exact correct time — the sequential-access nature of the technology means random writes and reads aren’t actually possible. The really cool thing is that [P-Lab] paired the memory with lots of LEDs to show how it works. There are lights to indicate the operation of the clock, and the read and write cycles, as well as individual LEDs indicating the status of each individual bit as they roll around the delay line. Combined with the hexadecimal readouts, it makes it easy to get to grips with this old-school way of doing things.
We’ve seen previous work from[P-Lab] in this regard
using old-school core rope memory, too.
[Thanks to Giuseppe for the tip!] | 9 | 5 | [
{
"comment_id": "8124282",
"author": "Quinn Evans",
"timestamp": "2025-05-04T12:12:00",
"content": "Acoustic delay lines (the coiled nickel wire mentioned) are great. Stomp hard enough next to the control box for the 3270s and corrupt everyone’s screen.",
"parent_id": null,
"depth": 1,
"... | 1,760,371,554.784022 | ||
https://hackaday.com/2025/05/04/frnisi-dmc-100-a-clamp-meter-worth-cracking-open/ | Frnisi DMC-100: A Clamp Meter Worth Cracking Open | Heidi Ulrich | [
"Teardown",
"Tool Hacks"
] | [
"clamp meter",
"dmc-100",
"flashlight",
"FNIRSI",
"probes"
] | Not all clamp meters are the same, and this video shows just that. In
a recent teardown by [Kerry Wong]
, the new Fnirsi DMC-100 proves that affordable doesn’t mean boring. This 10,000-count clamp meter strays from the classic rotary dial in favour of a fully button-based interface – a choice that’s got sparks flying in the comments. And yes, it even auto-resumes its last function after reboot, like it knows you’re busy frying other fish.
What sets this meter apart isn’t just its snappy interface or surprisingly nice gold-tipped probes. It’s the layered UX – a hackable interface where short- and long-presses unlock hidden menus, memory functions, and even a graphing mode. A proper “hold-my-beer” moment comes when you discover it can split-display voltage and current and calculate real-time power (albeit with a minor asterisk: apparent power only, no power factor). Despite a few quirks, like accidentally triggering the flashlight when squeezing the jaw, it holds up well in accuracy tests. Even at higher currents where
budget meters
usually wobble. | 17 | 7 | [
{
"comment_id": "8124227",
"author": "Cricri",
"timestamp": "2025-05-04T08:27:20",
"content": "Typo in title: FNIRSI, not FRNISI.",
"parent_id": null,
"depth": 1,
"replies": [
{
"comment_id": "8124235",
"author": "helge",
"timestamp": "2025-05-04T09:15:34",
... | 1,760,371,554.909512 |
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