Turning An ATX PSU Into A Variable Bench Supply

May 23, 2024 by 90 Comments

Bench power supplies can sometimes be frustratingly expensive and also kind of limited. If you’re enterprising and creative, though, you can create your own bench supply with tons of features, and it doesn’t have to break the bank either. Do what [Maker Y] did—grab an ATX supply and get building!

ATX power supplies work as a great basis for a bench power supply. They have 12 volt, 3.3 volt, and 5 volt rails, and they can supply a ton of current for whatever you might need. [Maker Y] decided to break out these rails on banana plugs for ease of access, and fused them for safety, too. But the build doesn’t stop there. [Maker Y] also added a buck-boost converter to provide a variable voltage output from 1 to 30 volts for added flexibility. As a nice final touch, the rig also features a pair of USB A ports compatible with Quick Charge 3.0, for keeping smart devices charged while working in the lab.

[Caelestis Workshop] also designed a fully enclosed version if you prefer that style. Check it out on Instructables.

No matter which way you go, it’s a pretty simple build, with a bunch of off-the-shelf parts tossed together in a 3D printed housing. Ultimately, though, it’s got more functionality than a lot of cheap off-the-shelf bench supplies. You can build it just about anywhere on Earth where you can get cheap eBay parts via post. Continue reading “Turning An ATX PSU Into A Variable Bench Supply” →

Grid Leak Radio Draws The Waves

May 23, 2024 by 11 Comments

[Stephen McNamera] found a schematic for a grid leak radio online and decided to throw together a few tubes on a piece of wood and see how it worked. As you can see in the video below, it works well. The video is a bit light on details, but the web page he found the plans on also has quite a bit of explanation.

The name “grid leak detector” is due to the grid leak resistor between the grid and ground, in this case, a 2.7 megaohm resistor. The first tube does everything, including AM detection. The second tube is just an audio amplifier that drives the speaker. This demodulation method relies on the cathode to control grid conduction characteristics and was found in radios up to about the 1930s. The control grid performs the usual function but also acts as a diode with the cathode, providing demodulation. In a way, this is similar to a crystal radio but with an amplified tube diode instead of a crystal.

It looks like [Stephen] wound his own coil, and the variable capacitor looks suspiciously like it may have come from an old AM radio. The of the old screw terminal tube sockets on the wood board looks great. Breadboard indeed! What we didn’t see is where the 150 V plate voltage comes from. You hope there is a transformer somewhere and some filter capacitors. Or, perhaps he has a high-voltage supply on the bench.

While tubes are technologically passe, we still like them. Especially in old radios. Just take care around the high voltages, please.

Continue reading “Grid Leak Radio Draws The Waves” →

An image of a grey plastic carrying case, approximately the size of an A5 notebook. Inside are darker grey felt lined cubbies with a mirror, piece of glass, a viewfinder, and various small printed parts to assemble a camera lucida.

Camera Lucida – Drawing Better Like It’s 1807

May 23, 2024 by 15 Comments

As the debate rages on about the value of AI-generated art, [Chris Borge] printed his own version of another technology that’s been the subject of debate about what constitutes real art. Meet the camera lucida.

Developed in the early part of the nineteenth century by [William Hyde Wollaston], the camera lucida is a seemingly simple device. Using a prism or a mirror and piece of glass, it allows a person to see the world overlaid onto their drawing surface. This moves details like proportions and shading directly to the paper instead of requiring an intermediary step in the artist’s memory. Of course, nothing is a substitute for practice and skill. [Professor Pablo Garcia] relates a story in the video about how [Henry Fox Talbot] was unsatisfied with his drawings made using the device, and how this experience was instrumental in his later photographic experiments.

[Borge]’s own contribution to the camera lucida is a portable version that you can print yourself and assemble for about $20. Featuring a snazzy case that holds all the components nice and snug on laser cut felt, he wanted a version that could go in the field and not require a table. The case also acts as a stand for the camera to sit at an appropriate height so he can sketch landscapes in his lap while out and about.

Interested in more drawing-related hacks? How about this sand drawing bot or some Truly Terrible Dimensioned Drawings?

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Is This The World’s Smallest Multichannel Voltmeter?

May 22, 2024 by 8 Comments

The instrument which probably the greatest number of Hackaday readers own is likely to be the humble digital multimeter. They’re cheap and useful, but they’re single-channel, and difficult to incorporate into a breadboard project. If you’ve ever been vexed by these limitations then [Alun Morris] has just the project for you, in the world’s smallest auto-ranging multichannel voltmeter. It’s a meter on a tiny PCB with a little OLED display, and as its name suggests, it can keep an eye on several voltages for you.

At its heart is an ATtiny1614 microcontroller on a custom PCB, but for us the part we most like lies not in that but in the prototype version made on a piece of protoboard. There’s considerable soldering skill in bending surface mount components to your will on this material, and though these aren’t quite the smallest parts it’s still something that must have required some work under the magnifier.

All of the code and hardware details can be found in the GitHub repository, and for your viewing pleasure there’s a video showing it in action which we’ve placed below.

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FLOSS Weekly Episode 784: I’ll Buy You A Poutine

May 22, 2024 by No comments

This week Jonathan Bennett and Dan Lynch talk with François Proulx about Poutine, the Open Source security scanner for build pipeline vulnerabilities. This class of vulnerability isn’t as well known as it should be, and threatens to steal secrets, or even allow for supply chain attacks in FLOSS software.

Poutine does a scan over an organization or individual repository, looking specifically for pipeline issues. It runs on both GitHub and GitLab, with more to come!

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Hands On: AD409-Max Microscope

May 22, 2024 by 18 Comments

It used to be that only the most well-equipped home electronics lab had a microscope. However, with SMD parts getting smaller and smaller, some kind of microscope is almost a necessity.

Luckily, you can get USB microscopes for a song now. If you’re willing to spend a little more, you can get even get microscopes that have little LCD screens. However, there are some problems with the cheaper end of these microscopes.

Many of them have small and wobbly stands that aren’t very practical. Some don’t leave you much room to get a soldering iron in between the lens and the part. Worse still, many cheap microscopes have trouble staying still when you have to push buttons or otherwise make adjustments to the device.

It seems like every time a new generation of microscopes aimed at the electronics market arrives on the scene, many of the earlier flaws get taken care of. That’s certainly the case with the Andonstar AD409-Max.

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90s PowerBook Runs MacOS Monterey

May 22, 2024 by 12 Comments

Even though Apple isn’t known for making the most pro-consumer devices ever (at least not since the Apple II), the trope that Apples aren’t upgradable, customizable, or otherwise hackable doesn’t really hold much weight. It does take more work to modify them or change how Apple wants them to behave, but it’s not completely impossible. Take this example of a ’94 Apple PowerBook which runs macOS Moneterey thanks largely to new internals from a 2015 MacBook Pro.

[Billy] originally intended for a Raspberry Pi to go inside this old PowerBook, but at the time, prices for ARM single-board computer (SBC) were astronomical. For around the same price as the Pi was at the time, he was able to pick up a retina display from an iPad and the internals from a broken MacBook Pro to outfit this retro case. There’s also a Teensy installed to get the trackpad working and a driver board for the display from Adafruit, and a number of case mods were needed to get everything to fit including the screen which was slightly larger than the original 9.5″ display the laptop would have shipped with.

This project took both inspiration and some of the actual code needed to get everything working from another project we featured a while ago where a Mac Mini was installed inside of a PowerBook case from 1993. Unlike projects that use smaller SBCs for retrocomputing, these builds are notable because the hardware on the inside makes them usable as daily driver computers even today, and might even be an upgrade if you’re using the internals from a MacBook Pro that would have originally had a butterfly keyboard.

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