Author: Jenny List

3288 Articles

2025 Component Abuse Challenge: The Slip Ring In Your Parts Bin

November 11, 2025 by 33 Comments

If you’re familiar with electrical slip rings as found in motors and the like you’ll know them as robust assemblies using carefully chosen alloys and sintered brushes, able to take the load at high RPM for a long time. But not all slip ring applications need this performance. For something requiring a lot less rotational ability, [Luke J. Barker] has something from his parts bin, and probably yours too. It’s an audio jack.

On the face of it, a 1/4″ jack might seem unsuitable for this task, being largely a small-signal audio connector. But when you consider its origins in the world of telephones it becomes apparent that perhaps it could do so much more. It works for him, but we’d suggest if you’d like to follow his example, to use decent quality plugs and sockets.

This is an entry in our 2025 Component Abuse Challenge, and we like it for thinking in terms of the physical rather than the electrical. The entry period for this contest will have just closed by the time you read this, so keep an eye out for the official results soon.

2025 Hackaday Component Abuse Challenge

Another Thermal Printer, Conquered

November 11, 2025 by 13 Comments

The arrival of cheap thermal printer mechanisms over the last few years has led to a burst of printer hacking in our community, and we’re sure many of you will like us have one knocking around somewhere. There are a variety of different models on the market, and since they often appear in discount stores we frequently see new ones requiring their own reverse engineering effort. [Mel] has done some work on just such a model, the Core Innovation CTP-500, which can be found at Walmart.

The write-up is a tale of Bluetooth reverse engineering as much as it is one about the device itself, as he sniffs the protocol it uses, and finds inspiration from the work of others on similar peripherals. The resulting Python app can be found in his GitHub repository, and includes a TK GUI for ease of use. We like this work and since there’s an analogous printer from a European store sitting on the Hackaday bench as we write this, it’s likely we’ll be giving it a very close look.

Meanwhile if [Mel] sounds a little familiar it might be because of their print-in-place PCB holder we featured recently.

“AI, Make Me A Degree Certificate”

November 10, 2025 by 139 Comments

One of the fun things about writing for Hackaday is that it takes you to the places where our community hang out. I was in a hackerspace in a university town the other evening, busily chasing my end of month deadline as no doubt were my colleagues at the time too. In there were a couple of others, a member who’s an electronic engineering student at one of the local universities, and one of their friends from the same course. They were working on the hardware side of a group project, a web-connected device which with a team of several other students, and they were creating from sensor to server to screen.

I have a lot of respect for my friend’s engineering abilities, I won’t name them but they’ve done a bunch of really accomplished projects, and some of them have even been featured here by my colleagues. They are already a very competent engineer indeed, and when in time they receive the bit of paper to prove it, they will go far. The other student was immediately apparent as being cut from the same cloth, as people say in hackerspaces, “one of us”.

They were making great progress with the hardware and low-level software while they were there, but I was saddened at their lament over their colleagues. In particular it seemed they had a real problem with vibe coding: they estimated that only a small percentage of their classmates could code by hand as they did, and the result was a lot of impenetrable code that looked good, but often simply didn’t work.

I came away wondering not how AI could be used to generate such poor quality work, but how on earth this could be viewed as acceptable in a university.
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Have They Found A Complete UNIX V4?

November 9, 2025 by 19 Comments

If you’ve ever combed boxes of old tech detritus in search of a nugget of pure gold, we know you’ll appreciate the excitement of discovering, in a dusty University of Utah storeroom, a tape labelled “UNIX Original from Bell Labs V4 (See manual for format)”. If the tape contains what’s promised on the label, this is a missing piece of computer history, because no complete copies of this version are known to exist.

The tape will be delivered by hand to the Computer History Museum, where we hope its contents will be safely retrieved for archive and analysis. The reporter of the find, research professor [Rob Ricci], identifies the handwriting as that of Jay Lepreau, someone whose word on which UNIX version it contained could, we hope, be trusted.

Continue reading “Have They Found A Complete UNIX V4?” →

2025 Component Abuse Challenge: Dawg Gone LED Tester

November 9, 2025 by 24 Comments

The Hackaday 2025 Component Abuse Challenge is all about abusing electronic components in the service of making them do things they were never intended to. It’s not the 2025 Food Abuse Challenge, so in the case of [Ian Dunn]’s hot dog pressed into service as an LED tester, we’ll take the ‘dawg to be a component in its own right. And by any measure, it’s being abused!

Cooking hot dogs by passing an electric current through them has a long and faintly hazardous history to it — we’re sure we’ve heard of domestic hot dog cooker appliances that are little more than the mains supply on a pin at each end of a hot dog shaped receptacle. This one takes the ‘dawg in a bun with condiments, no less, and sticks an ordinary table fork wired up to the grid in each end. The LED testing is the cherry on the cake, because he simply sticks a pile of LEDs by their pins into the tasty sausage. It forms a crude potential divider, so there’s about enough volts across the gap between pins to light it up nicely.

We like this project on so many levels, though we’re not sure what heavy metals would leach out of those LED pins into the meat. If it’s inspired you to do something similar you still have a few days in which to enter the contest, so break out your convenience food and a pile of parts, and start experimenting!

2025 Hackaday Component Abuse Challenge

2025 Component Abuse Challenge: Glowing Neon From A 9 V Relay

November 8, 2025 by 7 Comments

Most of us know that a neon bulb requires a significant voltage to strike, in the region of 100 volts. There are plenty of circuits to make that voltage from a lower supply, should you wish to have that comforting glow of old, but perhaps one of the simplest comes from [meinsamayhun]. The neon is lit from a 9-volt battery, and the only other component is a relay.

What’s going on? It’s a simple mechanical version of a boost converter, with the relay wired as a buzzer. On each “off” cycle, the magnetic field in the coil collapses, and instead of being harvested by a diode as with a boost converter, it lights the neon. Presumably, the neon also saves the relay contacts from too much wear.

We like this project for its simplicity and for managing to do something useful without a semiconductor or vacuum tube in sight. It’s the very spirit of our 2025 Component Abuse Challenge, for which there is barely time to enter yourself if you have something in mind.

2025 Hackaday Component Abuse Challenge

BIOS Detectives Find Ghost Of Previously Unknown PC

November 8, 2025 by 24 Comments

Old parts such as EPROMs will often find themselves for sale on sites such as eBay, where they are sometimes snapped up by retrocomputing enthusiasts in search of interesting code. Vintage Computer Federation forum member [GearTechWolf] picked up a clutch of IBM-labelled chips, and as int10h reports, stumbled upon a previously unknown PC-AT BIOS version which even hints at a rare PC model as yet unseen.

The IBM AT and its various versions are extremely well known in the retro PC world, so while this was quickly identified as an IBM BIOS from 1985 and narrowed down to a member of the AT family, it didn’t fit any of the known versions which shipped with the ubiquitous 1980s computer. Could it have been from an industrial or rack mount variant? It’s a possibility, but the conclusion is that it might contain a patched BIOS version of some kind.

Lacking real hardware, it happily boots on an emulator. It’s another piece of the PC historical jigsaw for people interested in computer history, and with luck in time someone will unearth an example of whatever it came from. If you find it, try a modern OS on it!