Replacing Selenium Rectifiers

September 24, 2024 by 13 Comments

Old radios often had selenium rectifiers to convert AC to DC. The problem is that the old units, dating back to 1933, are prone to failure and to release dangerous chemicals like hydrogen selenide. [M Caldeira] has a new board made to fit a particular rectifier and also allows a varying voltage drop. The circuit consists of a few diodes, a MOSFET, and a pot for adjusting the voltage drop. An IRF840 MOSFET provides the adjustment.

Did it work? It did. The good news is that if it fails — which shouldn’t happen very often — it won’t release stinky and noxious fumes

We wondered if he should 3D print a fake case to make it look more the part. If you haven’t seen a real selenium rectifier, they were made of stacks of metal plates coated with bismuth or nickel. Then, a film of doped selenium was annealed to the surface to form cadmium selenide. Each plate could handle about 20 V and the more plates you used, the more reverse voltage the device could withstand.

Selenium was also found in old photocells. If you fancy replacing other parts of an old radio, you might consider a faux magic eye or even one of the main tubes.

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Digital Audio Workstation In A Box

September 23, 2024 by 3 Comments

Although it’s still possible to grab a couple of friends, guitars, and a set of drums and start making analog music like it’s 1992 and there are vacant garages everywhere yearning for the sounds of power chords, the music scene almost demands the use of a computer now. There are a lot of benefits, largely that it dramatically lowers the barrier to entry since it greatly reduces the need for expensive analog instruments. It’s possible to get by with an impressively small computer and only a handful of other components too, as [BAussems] demonstrates with this tiny digital audio workstation (DAW).

The DAW is housed inside a small wooden box and is centered around a Behringer JT-4000 which does most of the heavy lifting in this project. It’s a synthesizer designed to be as small as possible, but [BAussems] has a few other things to add to this build to round out its musical capabilities. A digital reverb effects pedal was disassembled to reduce size and added to the DAW beneath the synthesizer. At its most basic level this DAW can be used with nothing but these components and a pair of headphones, but it’s also possible to add a smartphone to act as a sequencer and a stereo as well.

For a portable on-the-go rig, this digital audio workstation checks a lot of the boxes needed including MIDI and integration with a computer. It’s excellent inspiration for anyone else who needs a setup like this but doesn’t have access, space, or funds for a more traditional laptop- or desktop-centered version. For some other small on-the-go musical instruments we recently saw a MIDI-enabled keyboard not much larger than a credit card.

The Possibility Of Reverting Time On The Ageing Of Materials

September 23, 2024 by 7 Comments

Everyone knows that time’s arrow only goes in one direction, regardless of the system or material involved. In the case of material time, i.e. the ageing of materials such as amorphous materials resulting from glass transition, this material time is determined after the initial solidification by the relaxation of localized stresses and medium-scale reordering. These changes are induced by the out-of-equilibrium state of the amorphous material, and result in changes to the material’s properties, such as a change from ductile to a brittle state in metallic glasses. It is this material time which the authors of a recent paper (preprint) in Nature Physics postulates to be reversible.

Whether or not this is possible is said to be dependent on the stationarity of the stochastic processes involved in the physical ageing. Determining this stationarity through the investigation of the material time in a number of metallic glass materials (1-phenyl-1-propanol, laponite and polymerizing epoxy) was the goal of this investigation by [Till Böhmer] and colleagues, and found that at least in these three materials to be the case, suggesting that this process is in fact reversible.

Naturally, the primary use of this research is to validate theories regarding the ageing of materials, other aspects of which have been investigated over the years, such as the atomic dynamics by [V.M Giordano] and colleagues in a 2016 paper in Nature Communications, and a 2022 study by [Birte Riechers] and colleagues in Science Advances on predicting the nonlinear physical ageing process of glasses.

While none of these studies will give us time-travel powers, it does give us a better understanding of how materials age over time, including biological systems like our bodies. This would definitely seem to be a cause worthy of our time.

Header image: Rosino on Flickr, CC BY-SA 2.0.

Find My Power Tool Battery

September 23, 2024 by 7 Comments

Apple’s Find My network has seen its fair of hacks to devices, but perhaps the most unusual we’ve seen is before us today. [biemster] has added a Lidl Parkside smart connected power tool battery to the network, not by concealing an AirTag within it, but by hacking its on-board firmware.

Opening up the device reveals a Tuya BT17L Bluetooth module, the hackable nature of which due to other projects prompted a port of a previous Find My project which provided open source access to the network. The result is as he describes, the world’s chunkiest key finder, and also we’re guessing the one with one of the longest battery lives too.

The European budget supermarkets are well known for their budget bargain aisles, and Lidl’s Parkside range has some surprisingly robust tools among it. They might not quite be up to replacing IKEA in the hacker source stakes, but those of us who live in countries served by them know to keep an eye out in the hope of fresh gems alongside those awesome AlpenFest apple crumble cakes. This one certainly isn’t the first Parkside hack we’ve seen.

A series of wooden rectangles are arranged vertically around the edges of a dark wooden base, reminiscent of a very tall radial fan. Light glows from the base up the slots between the vanes. a cord runs from behind the dark base to a small puck of the same color. The setup sits on a light grey table in front of a light grey wall.

A Beautiful Lamp-Inspired PC Case

September 23, 2024 by 4 Comments

Sometimes you see something super cool and think of how it would be really neat if applied in a totally different context. [MXC Builds] saw an awesome lamp from [karacreates], but decided it would be better as a PC case.

We love seeing how different techniques can be used in conjunction to make something that no one method could produce on its own, and for this build, we see [MXC Builds] use 3D printing, laser cutting, CNC, sewing, soldering, and traditional woodworking techniques.

A large part of the video is spent on the CNC process for the walnut base and power button enclosure for the build. As with any project, there are a few places requiring some creative use of the tools on hand, like the walnut piece for the base being too tall for the machine’s usual z-calibration puck or any of [MXC Builds]’s bits to do in one pass, and it’s always interesting to see how other makers solve these issues.

If you’re looking for other beautiful casemods, how about a transparent PS2 or this Art Deco number? Before you go, may we bend your ear about how PC Cases are Still Stuck in the Dark Ages?

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Custom Mini-Neon Signs In 10 Minutes

September 23, 2024 by 22 Comments

Sometimes, you see a project that isn’t a technical powerhouse but just looks so good you can’t help but think about duplicating it. That’s how we felt with the mini-neon signs made by [makerverse]. From an electronics point of view, it is just some filament LEDs and a 3D-printed casing. But, as you’ll see in the video below, these look like little miniature neon signs, and they look great.

Although we might use a different set of tools to get there, the idea is to create your text in DXF, extrude it in CAD, and then print a dark shell with a light or translucent center using a filament change. Glow-in-the-dark filament is also an option. Obviously, if you are handy in any CAD tool, you could easily pull this off.

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Revisiting 1990’s Mac Games That Never Were

September 23, 2024 by 16 Comments

[John Calhoun] was digging around their old MAC hard drives, revisiting some abandoned shareware games they wrote over three decades ago, and has uploaded the recovered disk images to GitHub for everyone to take apart and play with. This repository has a few of the games complete with their development files and the compiler environment, a mixture of Think Pascal and C.

Back then, [John] had a solid mantra when creating projects, specifically prototyping fast and abandoning things quickly if they were not working out. The blog shows a list of twenty-eight projects, of which only five ever made it to release, with all the rest left to rot. This is reminiscent of the attitude around Silicon Valley of moving fast and breaking things. Anyway, reasons for ditching a project ranged from ‘too much sprite work’ for a D’n’D style game to simply ‘not fun’ for some with clunky control mechanisms. [John] even abandoned a neat-looking steampunk flight simulator due to the sheer amount of work needed. Of course, it’s not all lost effort. Much of the code written was reused across multiple projects; after all, there’s no point in re-writing a cosine lookup table if you’ve already got one kicking around in another project.

Still, it’s a fun trip down memory lane, looking deep into projects that never were and the development journey to becoming a successful programmer.

While it isn’t hard to find old Macintosh hardware, some are not in great shape. Here’s a fun Hackintosh project that uses retro parts. [John] was featured a while back, with his homage to his first mac, a sleek Rpi-powered eInk desk ornament. Finally, we can’t talk about recovering retro software without looking in detail at the floppy disk themselves.