Hackaday Podcast Episode 345: A Stunning Lightsaber, Two Extreme Cameras, And Wrangling Roombas

It’s a wet November evening across Western Europe, the steel-grey clouds have obscured a rare low-latitude aurora this week, and Elliot Williams is joined by Jenny List for this week’s podcast. And we’ve got a fine selection for your listening pleasure!

The 2025 Component Abuse Challenge has come to an end, so this week you’ll be hearing about a few of the entries. We’ve received an impressive number, and as always we’re bowled over by the ingenuity of Hackaday readers in pushing parts beyond their limits.

In the news is the potential discovery of a lost UNIX version in a dusty store room at the University of Utah, Version 4 of the OS, which appeared in 1973. Check out your own stores, for hidden nuggets of gold. In the hacks, we have two cameras at the opposite end of the resolution spectrum, but sharing some impressive reverse engineering. Mouse cameras and scanner cameras were both a thing a couple of decades ago, and it’s great to see people still pushing the boundaries. Then we look at the challenge of encoding Chinese text as Morse code, an online-upgraded multimeter, the art of making lenses for an LED lighting effect, and what must be the best recreation of a Star Wars light sabre we have ever seen. In quick hacks we have a bevvy of Component Abuse Challenge projects, a Minecraft server on a smart light bulb, and a long term test of smartphone battery charging techniques.

We round off with a couple of our long-form pieces, first the uncertainties about iRobot’s future and what it might mean for their ecosystem — think: cheap hackable robotics platform! — and then a look at FreeBSD as an alternative upgrade path for Windows users. It’s a path not without challenges, but the venerable OS still has plenty to give.

As always, you can listen using the links below, and we’ve laidout links to all the articles under discussion at the bottom of the page.

Download our finest MP3 right here.

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The Pi 500 Turned Overkill Bluetooth Keyboard

Perhaps we’ve all found ourselves at one time or another with more computers in use than keyboards and other peripherals at hand to use them with. With a single user you can make do with remote terminals or by simply plugging and unplugging, but with multiple users it’s not so easy.

CNX Software’s [Jean-Luc Aufranc] had just such a problem involving broken keyboards and a forgotten wireless dongle, but fortunately he had just reviewed the latest version of the Raspberry Pi 500 all-in-one computer with the fancy mechanical switches. His keyboard solution is inspired but completely overkill: to use the full power of the compact Linux machine to emulate a Bluetooth keyboard.

At the heart of this hack is btferret, a Bluetooth library. Run the appropriate software on your Pi, and straight away you’ll have a Bluetooth keyboard. It seems there’s a bit of keymap tomfoolery to be had, and hitting the escape key terminates the program — we would be caught by that SO many times! — but it’s one of those simple hacks it pays to know about in case like him you need to get out of a hole and happen to have one of the range of Pi all-in-one machines to hand.

2025 Component Abuse Challenge: Light An LED With Nothing

Should you spend some time around the less scientifically informed parts of the internet, it’s easy to find “Free power” stories. Usually they’re some form of perpetual motion machine flying in the face of the laws of conservation of energy, but that’s not to say that there is no free power.

The power just has to come from somewhere, and if you’re not paying for it there’s the bonus. [joekutz] has just such a project, lighting up LEDs with no power source or other active electronics.

Of course, he’s not discovered perpetual motion. Rather, while an LED normally requires a bit of current to light up properly, it seems many will produce a tiny amount of light on almost nothing. Ambient electromagnetic fields are enough, and it’s this effect that’s under investigation. Using a phone camera and a magnifier as a light detector he’s able to observe the feeble glow as the device is exposed to ambient fields.

In effect this is using the LED as the very simplest form of radio receiver, a crystal set with no headphone and only the leads, some wires, and high value resistors as an antenna. The LED is after all a diode, and it can thus perform as a rectifier. We like the demonstration even if we can’t quite see an application for it.

While we’re no longer taking new entries for the 2025 Component Abuse Challenge, we’ve still got plenty of creative hacks from the competition to show off. We’re currently tabulating the votes, and will announce the winners of this particularly lively challenge soon.

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

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.

Another Thermal Printer, Conquered

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”

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?

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.

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