A Raspberry Pi Pico 2 W connected to a speaker

Voice Control Toolkit Comes To A Pico Near You

July 23, 2026 by Julian Scheffers 4 Comments

Voice-controlled appliances are nothing new. What might be new, however, is [Moonshine AI] running it all locally on a Raspberry Pi Pico 2 W!

The voice interface is roughly divided into three parts: voice activity detection, SpellingCNN speech-to-text and a neural text to speech. The speech to text supports up to 50 tokens, and can be re-trained to support any specific words you want. It runs a simple loop: detect voice activity, listen for (command) tokens, process them in C++, use the TTS to reply, and repeat.

Now, to be fair, it is a bit of a squeeze: 3.6 MiB of the available 4 MiB FLASH and 468 KiB SRAM on a stock Pi Pico 2 board. It leaves you with just about enough space to write a small amount of extra software, but it’ll be a challenge to fit anything substantial. Still, fitting three different types of AI model needed to make this possible in such a space is quite impressive.

Old TV Vacuum Tube Turned DIY X-Ray Machine

July 22, 2026 by Julian Scheffers 27 Comments

Just because you probably shouldn’t make a DIY X-ray machine, doesn’t mean nobody would. [mircemk] shows off his DIY unit, how it works, how to use it safely and of course, some pretty X-ray photos of household objects.

The machine repurposes a DY86 vacuum tube from old CRT TVs to emit X-ray radiation. To drive the tube without blowing it up, a rather specialized series of power supplies is needed; a low-voltage DC power supply powers a high-voltage AC inverter, which is then sent through first a transformer, and then a Crockfort-Walton voltage multiplier, to reach the incredibly high voltages needed for such a vacuum tube’s radiation emission to reach X-rays. Naturally, this didn’t go to plan first try, leading to the unfortunate demise of three vacuum tubes (as well as another three which had already lost their vacuums).

Now how do you capture an image with X-rays for a light source? With dental X-ray photo films of course! The dental film is placed behind the object to be scanned, the transmitted X-rays making up the resulting image. After going through the standard process of developing for about 30s, washing, fixing for about half an hour, and washing again, the photos become clearly visible. The best results were obtained at a distance of 10-15 cm an an exposure time varying from 15 minutes to an hour depending on material hardness.

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Drawing Videos On An Etch-a-Sketch

May 26, 2026 by Julian Scheffers 2 Comments

We’ve covered etch-a-sketch robots before, but usually they’re not quite as fast as [Every Flavor of Robot]’s “video” etch-a-sketch, capable of drawing a full portrait in as little as a minute.

The robot, nearly finished drawing a portrait of [William Osman]

The idea comes from the motivation to make something cool for Open Sauce. Of course, most projects with a deadline come very close to missing it, and–like many an Open Sauce project–this one is no exception. Arriving in California, they realize they couldn’t access their code! Fortunately, they get a demo working where your portrait is drawn just in time.
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Lost Version Of Amiga Unix Suddenly Reappears

May 25, 2026 by Julian Scheffers 10 Comments

Some of you may know there’s a version of UNIX for the Commodore Amiga, aptly called Amiga Unix or AMIX. There is an almost complete record of versions from 1.0 to 2.03, but 2.02 was lost media–until [Forgotten Computer] found it on an old Amiga.

It starts with an auction held for the 40 year anniversary of the Free Software Foundation where, by just one second, the highest bidder was too late. What do you do first with an artifact as valuable as an old FSF computer? You image the hard drive. Then you make several copies, including on different computers–after all, you wouldn’t want to lose the data on it. Preservation secured, the natural next thing is to boot it–and that’s when we see the magic 2.02c version number.
According to thorough digging by [Forgotten Computer], this version was–until now–lost.

In the video after the break, [Forgotten Computer] goes over what Amiga Unix is, the discovery process, and explores what’s on the disk–including FSF staples like GCC, G++ and core utilities like GNU less.
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Passive Bug Zapper Tracks Its Kill Count

May 23, 2026 by Julian Scheffers 32 Comments

If it’s summer in a warm, humid climate, bugs can be the bane of your existence. A natural solution is to place a passive bug zapper to catch bugs at night. But what if that isn’t fancy enough? [Nicolas Boichat] spices it up with a passive bug zapper that tracks its kill count.

But how exactly do you detect a bug zap? With an antenna, of course! When a bug gets caught, it arcs, creating an electromagnetic pulse. A small loop antenna on the backside of the zapper receives the signal.
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A desk fan with an air filter. On the side, the final assembled PCB is visible.

Making A PCB The Old-Fashioned Way

May 21, 2026 by Julian Scheffers 59 Comments

Nearly all modern PCBs are designed with the help of EDA software, but not all of them. [ALTco] shows us the process of plotting out a board the old-fashioned way — by hand.

Back in the day, drawing out the traces on a PCB lead to beautiful, smooth lines that [ALTco] wanted to imitate. But first, he needed to figure out how the rest of the fabrication process worked. He starts by just experimenting, both with the “resist” markers and paint, and the etching compound. Things rarely work first-try, and neither did his home-made etchant. So then it was time to buy some ferric chloride, the standard copper etchant for PBCs. A few more tests sorted out which permanent marker worked best.

[ALTco] starts by thoroughly cleaning a raw copper-clad board so the marker sticks properly, then draws the circuit for a little analog fan controller. The board is then laid in a bath of the etchant for several minutes while gently rocking it to keep the reaction going. Finally the board is taken out, etchant stored for re-use, and the board washed with water and then presumably IPA to remove the remaining marker. Some assembly of the newly-printed circuit board later and you have a cute little smoke absorber for your soldering projects.

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A render of the moon, on a circular display.

Put The Moon On Your Desk

May 20, 2026 by Julian Scheffers 8 Comments

Most people take the Moon for granted, not considering its slow cycle where the sun gradually illuminates different parts of it. A recent project from [Karsten Mueller] helps you keep our nearest celestial neighbor in mind by putting a tiny version on your desk. (German)

The device itself is made with a circular display, an ESP32-S3, and a simple 3D printed case. But the interesting part is the software — it’s not just a moon phase display, it actually takes your local time, latitude and longitude into account. The resulting image is an approximation of what the moon looks like if you were to look at it, even if you wouldn’t actually be able to see it, such as when it is obscured by the Earth or barely visible during the daylight sky. Initially the project actually used a photograph of the Moon that [Karsten] personally snapped, but there’s also an option to pull the imagery from NASA.

The original write-up is in German, but there’s also an English page for the project on Hackaday.io, and the source is available on GitHub if you’d like to put one together yourself.