Silent Speak And Spell Gets Its Voice Back

August 18, 2025 by 4 Comments

While talking computers are old hat today, in 1978, a talking toy like the Speak and Spell was the height of novel tech. [Kevin] found a vintage one, but it didn’t work. It looked like someone had plugged in the wrong power adapter, leading to, undoubtedly, one or more unhappy children. There was some damage that suggests someone had already tried to repair it, but without success.

In addition to effecting the repair, [Kevin] took lots of pictures, so if you ever wanted to peek inside one of these, this is your chance. The case had no screws, just clips, although apparently some of the newer models did have some screws.

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The PC In Your Pico

August 18, 2025 by 33 Comments

We’re all used to emulating older computers here, and we’ve seen plenty of projects that take a cheap microcontroller and use it to emulate a classic home computer or gaming platform. They’re fun, but serve mostly as a way to relive old toys.

As microcontrollers become faster though it’s inevitable that the machines they can emulate become more powerful too, so we’re moving into the realm of emulating productivity machines from years past. An example is [Ilya Maslennikov]’s pico-286, which as its name suggests, is a 286 PC emulator for the Raspberry Pi Pico.

It has an impressive set of sound and video card emulations, can drive either a VGA or an HDMI monitor, and uses a PS/2 keyboard and mouse. If DOS games are your thing it should provide what you want, but it’s caught our eye because there was a time when a 286 DOS PC was a productivity machine. There’s a huge library of still-useful software for DOS, and thus the prospect of a handheld DOS PC still has some appeal. We’d love to see someone put this in a badge.

MS-DOS may no longer be for sale, but there are several ways to land an open-source DOS in 2025. FreeDOS is something of a powerhouse.

Adjustable Allen Key After All These Years

August 18, 2025 by 40 Comments

The Allen key turns 115 this year. It’s strange to believe that in all that time, no one has come up with an adjustable version, but apparently true. Luckily [Chronova Engineering] has taken up the challenge in his latest video.

The video is a fascinating glimpse at the toolmaker’s art–manual machining and careful human judgement. Humans being the fallable creatures we are, the design goes through a few iterations. After the first failure in metal, [Chronova] falls back on 3D printing to rapidly prototype the next six iterations. Given how much work goes into manually machining the designs, we can only imagine the time savings that represents.

The final version is has classic hexagonal rod split in two, so that a chisel-shaped rod can spread the two prongs out to engage the sides of the Allen bolt. Even with that settled, the prongs and wedge had to be redesigned several times to find exact shape and heat-treatment that would work. At this point the range is anything between 4 mm and 6 mm, which is admittedly narrow, but [Chronova Engineering] believes the mechanism has the potential to go wider.

The design is not being patented, but the drawings are available via the [Chronova Engineering] Patreon if you really need an adjustable Allen key and don’t feel like reverse-engineering the mechanism from video. It’s a much larger project than we’ve featured from this channel before– enormous, really, compared to steam engines that fit on pencil erasers or electric motors that squeeze through the eye of a needle.

Our thanks hall-of-fame tipster [Keith Olson] for letting us know about this one. If you want a slice of that fame for yourself, the tips line is always open. Continue reading “Adjustable Allen Key After All These Years” →

I, 3D Printer

August 18, 2025 by 3 Comments

Like many of us, [Ben] has too many 3D printers. What do you do with the old ones? In his case, he converted it into a robotic camera rig. See the results, including footage from the robot, in the video below. In addition to taking smooth video, the robot can spin around to take photos for photogrammetry.

In fact, the whole thing started with an idea of building a photogrammetry rig. That project didn’t go as well as planned, but it did lead to this interesting project.

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2025 One Hertz Challenge: Timekeeping At One Becquerel

August 18, 2025 by 23 Comments

The Becquerel (Bq) is an SI unit of radioactivity: one becquerel is equivalent to one radioactive decay per second. That absolutely does not make it equivalent to one hertz — the random nature of radioactive decay means you’ll never get one pulse every second — but it does make it interesting. [mihai.cuciuc] certainly thought so, when he endeavored to create a clock that would tick at one becquerel.

The result is an interesting version of a Vetinari Clock, first conceived of by [Terry Pratchett] in his Discworld books. In the books, the irregular tick of the clock is used by Lord Vetinari as a form of psychological torture. For some reason, imposing this torture on ourselves has long been popular amongst hackers.

Without an impractical amount of shielding, any one-becquerel source would be swamped by background radiation, so [mihai] had to get creative. Luckily, he is the creator of the Pomelo gamma-ray spectroscope, which allowed him to be discriminating. He’s using an Am-241 source, but just looking for the characteristic 59.5 KeV gamma rays was not going to cut it at such a low count rate. Instead he’s using two of the Pomelo solid-state scintillation as a coincidence detector, with one tuned for the Am-241’s alpha emissions. When both detectors go off simultaneously, that counts as an event and triggers the clock to tick.

How he got exactly one becquerel of activity is a clever hack, too. The Am-241 source he has is far more active than one decay per second, but by varying the distance from the gamma detector he was able to cut down to one detection per second using the inverse square law and the shielding provided by Earth’s atmosphere. The result is a time signal that is a stable one hertz… if averaged over a long enough period. For now, anyway. As the Am-241 decays away, its activity decreases, and [mihai] admits the clock loses about 0.4 seconds per day.

While we won’t be giving the prize for accuracy in this contest, we are sure Lord Vetinari would be proud. The Geiger-counter sound effect you can hear in the demo video embedded below is great touch. It absolutely increases the psychic damage this cursed object inflicts.

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How Laser Headlights Died In The US

August 18, 2025 by 141 Comments

Automotive headlights started out burning acetylene, before regular electric lightbulbs made them obsolete. In due time, halogen bulbs took over, before the industry began to explore even newer technologies like HID lamps for greater brightness. Laser headlights stood as the next leap forward, promising greater visibility and better light distribution.

Only, the fairytale didn’t last. Just over a decade after laser headlights hit the market, they’re already being abandoned by the manufacturers that brought them to fruition. Laser headlights would end up fighting with one hand behind their back, and ultimately became irrelevant before they ever became the norm.

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Should You Try Printing With Polypropylene?

August 18, 2025 by 11 Comments

Of all the plastics that surround us on the daily, the one we hear least about in the 3D printing world is probably polypropylene (PP). Given that this tough, slightly flexible thermoplastic has characteristics you might want for your prints, the question is: why? [Lost in Tech] is not answering that question in a recent video; instead he’s showing us what we’re missing out on with a review of the material.

A look at the Material Safety Data Sheet and available material has [Lost in Tech] suggesting it won’t be (much) more toxic for you than PLA, but you still wouldn’t want to huff the fumes. The biggest issue printing PP is getting it to stick — glass beds and PEI are not your friend, but polypropylene tape is easy to find and makes a fine print surface. He reviews a few other options, but it looks like plain old tape is still your best bet if you can’t get a hold of a Prusa PP bed. The other big issue is shrinkage, but that’s hardly unique to PP and can be accounted for in the model.

Just because it can be used, that doesn’t mean it should be. [Lost in Tech] does make a good case for why you might want to use PP — for one thing, it doesn’t string much, in part because it’s not hygroscopic. That makes it great for those of us in humid climes who don’t want to always faff around with dry boxes, but also wonderful for parts that will be in touch with water. Polypropylene also has great chemical resistance for even scarier chemicals than dihydrogen monoxide. The “killer app” though, at least as far as [Lost in Tech] is concerned, is to use polypropylene with compliant mechanisms: it’s incredibly resilient to bending, and doesn’t fatigue easily. You might even call it a “flexible” filament, but unlike with TPU, you get a nice hard plastic to go with that flexibility.

If you’re interested in this somewhat-forgotten filament, we featured a “getting started” guide last year. You can even make your own polypropylene filament using non-medical “COVID” masks, but do be sure to wash them first. What do you think? Is it time to give PP another chance, or has the 3D printing world moved on? Continue reading “Should You Try Printing With Polypropylene?” →