C Project Turns Into Full-Fledged OS

October 14, 2025 by Bryan Cockfield 6 Comments

While some of us may have learned C in order to interact with embedded electronics or deep with computing hardware of some sort, others learn C for the challenge alone. Compared to newer languages like Python there’s a lot that C leaves up to the programmer that can be incredibly daunting. At the beginning of the year [Ethan] set out with a goal of learning C for its own sake and ended up with a working operating system from scratch programmed in not only C but Assembly as well.

[Ethan] calls his project Moderate Overdose of System Eccentricity, or MooseOS. Original programming and testing was done in QEMU on a Mac where he was able to build all of the core components of the operating system one-by-one including a kernel, a basic filesystem, and drivers for PS/2 peripherals as well as 320×200 VGA video. It also includes a dock-based GUI with design cues from operating systems like Macintosh System 1. From that GUI users can launch a few applications, from a text editor, a file explorer, or a terminal. There’s plenty of additional information about this OS on his GitHub page as well as a separate blog post.

The project didn’t stay confined to the QEMU virtual machine either. A friend of his was throwing away a 2009-era desktop which [Ethan] quickly grabbed to test his operating system on bare metal. There was just one fault that the real hardware threw that QEMU never did, but with a bit of troubleshooting it was able to run. He also notes that this was inspired by a wiki called OSDev which, although a bit dated now, is a great place to go to learn about the fundamentals of operating systems. We’d also recommend checking out this project that performs a similar task but on the RISC-V instruction set instead.

A photo of the old mechanical and new digital altimeters

Ben Eater Explains How Aircraft Systems Communicate With The ARINC 429 Protocol

October 14, 2025 by John Elliot V 3 Comments

Over on his YouTube channel the inimitable [Ben Eater] takes a look at an electronic altimeter which replaces an old mechanical altimeter in an airplane.

The old altimeter was entirely mechanical, except for a pair of wires which can power a backlight. Both the old and new altimeters have a dial on the front for calibrating the meter. The electronic altimeter has a connector on the back for integrating with the rest of the airplane. [Ben] notes that this particular electronic altimeter is only a backup in the airplane it is installed in, it’s there for a “second opinion” or in case of emergency.

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Standalone CNC Tube Cutter/Notcher Does It With Plasma

October 14, 2025 by Tyler August 7 Comments

Tubes! Not only is the internet a series of them, many projects in the physical world are, too. If you’re building anything from a bicycle to a race cart to and aeroplane, you might find yourself notching and welding metal tubes together. That notching part can be a real time-suck. [Jornt] from HOMEMADE MADNESS (it’s so mad you have to shout the channel name, apparently) thought so when he came up with this 3-axis CNC tube notcher.

If you haven’t worked with chrome-molly or other metal tubing, you may be forgiven for wondering what the big deal is, but it’s pretty simple: to get a solid weld, you need the tubes to meet. Round tubes don’t really want to do that, as a general rule. Imagine the simple case of a T-junction: the base of the T will only meet the crosspiece in a couple of discreet points. To get a solid joint, you have to cut the profile of the crosspiece from the end of the base. Easy enough for a single T, but for all the joins in all the angles of a space-frame? Yeah, some technological assistance would not go amiss.

Which is where [Jornt]’s project comes in. A cheap plasma cutter sits on one axis, to cut the tubes as they move under it. The second axis spins the tube, which is firmly gripped by urethane casters with a neat cam arrangement. The third axis slides the tube back and forth, allowing arbitarily long frame members to be cut, despite the very compact build of the actual machine. It also allows multiple frame members to be cut from a single long length of tubing, reducing setup time and speeding up the overall workflow. Continue reading “Standalone CNC Tube Cutter/Notcher Does It With Plasma” →

2025 Component Abuse Challenge: Making A TTL Demultiplexer Sweat

October 14, 2025 by Jenny List 6 Comments

When we think of a motor controller it’s usual to imagine power electronics, and a consequent dent in the wallet when it’s time to order the parts. But that doesn’t always have to be the case, as it turns out that there are many ways to control a motor. [Bram] did it with a surprising part, a 74ACT139 dual 4-line demultiplexer.

A motor controller is little more than a set of switches between the supply rails and the motor terminals, and thus how it performs depends on a few factors such as how fast it can be switched, how much current it can pass, and how susceptible it is to any back EMF or other electrical junk produced by the motor.

In this particular application the motor was a tiny component in a BEAM robot, so the unexpected TTL motor controller could handle it. The original hack was done a few decades ago and it appears to have become a popular hack in the BEAM community.

This project is part of the Hackaday Component Abuse Challenge, in which competitors take humble parts and push them into applications they were never intended for. You still have time to submit your own work, so give it a go!

OpenSCAD In Living Color

October 14, 2025 by Al Williams 4 Comments

I modified a printer a few years ago to handle multiple filaments, but I will admit it was more or less a stunt. It worked, but it felt like you had to draw mystic symbols on the floor of the lab and dance around the printer, chanting incantations for it to go right. But I recently broke down and bought a color printer. No, probably not the one you think, but one that is pretty similar to the other color machines out there.

Of course, it is easy to grab ready-made models in various colors. It is also easy enough to go into a slicer and “paint” colors, but that’s not always desirable. In particular, I like to design in OpenSCAD, and adding a manual intervention step into an otherwise automatic compile process is inconvenient.

The other approach is to create a separate STL file for each filament color you will print with. Obviously, if your printer can only print four colors, then you will have four or fewer STLs. You import them, assign each one a color, and then, if you like, you can save the whole project as a 3MF or other file that knows how to handle the colors. That process is quick and painless, so the question now becomes how to get OpenSCAD to put out multiple STLs, one for each color.

But… color()

OpenSCAD has a color function, but that just shows you colors on the screen, and doesn’t actually do anything to your printed models. You can fill your screen with color, but the STL file you export will be the same. OpenSCAD is also parametric, so it isn’t that hard to just generate several OpenSCAD files for each part of the assembly. But you do have to make sure everything is referenced to the same origin, which can be tricky.

It turns out, the development version of OpenSCAD has experimental support for exporting 3MF files, which would allow me to sidestep the four STLs entirely. However, to make it work, you not only have to run the development version, but you also have to enable lazy unions in the preferences. You might try it, but you might also want to wait until the feature is more stable.

Besides, even with the development version, at least as I tried it, every object in the design will still need its color set in the slicer. The OpenSCAD export makes them separate objects, but doesn’t seem to communicate their color in a way that the slicer expects it. If you have a large number of multi-color parts, that will be a problem. It appears that if you do go this way, you might consider only setting the color on the very top-most objects unless things change as the feature gets more robust.

A Better Way

What I really wanted to do is create one OpenSCAD file that shows the colors I am using on the screen. Then, when I’m ready to generate STL files, I should be able to just pick one color for each color I am using.

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Making The Tiny Air65 Quadcopter Even Smaller

October 14, 2025 by Maya Posch 12 Comments

First person view (FPV) quadcopter drones have become increasingly more capable over the years, as well as much smaller. The popular 65 mm format, as measured from hub to hub, is often considered to be about the smallest you can make an FPV drone without making serious compromises. Which is exactly why [Hoarder Sam] decided to make a smaller version that can fit inside a Pringles can, based on the electronics used in the popular Air65 quadcopter from BetaFPV.

The 22 mm FPV drone with camera installed and looking all cute. (Credit: Hoarder Sam)

The basic concept for this design is actually based on an older compact FPV drone design called the ‘bone drone’, so called for having two overlapping propellers on each end of the frame, thus creating a bone-like shape. The total hub-to-hub size of the converted Air65 drone ends up at a cool 22 mm, merely requiring a lot of fiddly assembly before the first test flights can commence. Which raises the question of just how cursed this design is when you actually try to fly with it.

Obviously the standard BetaFPV firmware wasn’t going to fly, so the next step was to modify many parameters using the Betaflight Configurator software, which unsurprisingly took a few tries. After this, the fully loaded drone with camera and battery pack, coming in at a whopping 25 grams, turns out to actually be very capable. Surprisingly, it flies not unlike an Air65 and has a similar flight time, losing only about 30 seconds of the typical three minutes.

With propellers sticking out at the top and bottom – with no propeller guards – it’s obviously a bit of a pain to launch and land. But considering what the donor Air65 went through to get to this stage, it’s honestly quite impressive that this extreme modification mostly seems to have altered its dimensions.

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The Great Northeast Blackout Of 1965

October 14, 2025 by Dan Maloney 21 Comments

At 5:20 PM on November 9, 1965, the Tuesday rush hour was in full bloom outside the studios of WABC in Manhattan’s Upper West Side. The drive-time DJ was Big Dan Ingram, who had just dropped the needle on Jonathan King’s “Everyone’s Gone to the Moon.” To Dan’s trained ear, something was off about the sound, like the turntable speed was off — sometimes running at the usual speed, sometimes running slow. But being a pro, he carried on with his show, injecting practiced patter between ad reads and Top 40 songs, cracking a few jokes about the sound quality along the way.

Within a few minutes, with the studio cart machines now suffering a similar fate and the lights in the studio flickering, it became obvious that something was wrong. Big Dan and the rest of New York City were about to learn that they were on the tail end of a cascading wave of power outages that started minutes before at Niagara Falls before sweeping south and east. The warbling turntable and cartridge machines were just a leading indicator of what was to come, their synchronous motors keeping time with the ever-widening gyrations in power line frequency as grid operators scattered across six states and one Canadian province fought to keep the lights on.

They would fail, of course, with the result being 30 million people over 80,000 square miles (207,000 km²) plunged into darkness. The Great Northeast Blackout of 1965 was underway, and when it wrapped up a mere thirteen hours later, it left plenty of lessons about how to engineer a safe and reliable grid, lessons that still echo through the power engineering community 60 years later.

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