First Transistor Computer Reborn

September 21, 2025 by 15 Comments

Ok, we’ll admit it. If you asked us what the first transistorized computer was, we would have guessed it was the TC from the University of Manchester. After all, Dr. Wilkes and company were at the forefront and had built Baby and EDSAC, which, of course, didn’t use transistors. To be clear, we would have been guessing, but what we didn’t know at all was that the TC, with its magnetic drums and transistors in 1955, had a second life as a commercial product from Metropolitan-Vickers, called the Metrovick 950. [Nina Kalinina] has a simulator inspired by the old machine.

The code is in Python, and you can find several programs to run on the faux machine, including the venerable lunar lander. If you haven’t heard of the Metrovick, don’t feel bad. Oral histories say that only six or seven were ever built, and they were used internally within the company.

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Hackaday Links: September 21, 2025

September 21, 2025 by 7 Comments

Remember AOL? For a lot of folks, America Online was their first ISP, the place where they got their first exposure to the Internet, or at least a highly curated version of it. Remembered by the cool kids mainly as the place that the normies used as their ISP and for the mark of shame an “@aol.com” email address bore, the company nevertheless became a media juggernaut, to the point that “AOL Time Warner” was a thing in the early 2000s. We’d have thought the company was long gone by now, but it turns out it’s still around and powerful enough of a brand that it’s being shopped around for $1.5 billion. We’d imagine a large part of that value comes from Yahoo!, which previous owner Verizon merged with AOL before selling most of the combined entity off in 2021, but either way, it’s not chump change.

For our part, the most memorable aspect of AOL was the endless number of CDs they stuffed into mailboxes in the 90s. There was barely a day that went by that one of those things didn’t cross your path, either through the mail or in free bins at store checkouts, or even inside magazines. They were everywhere, and unless you were tempted by the whole “You’ve got mail!” kitsch, they were utterly useless; they didn’t even make good coasters thanks to the hole in the middle. So most of the estimated 2 billion CDs just ended up in the trash, which got us thinking: How much plastic was that? A bit of poking around indicates that a CD contains about 15 grams of polycarbonate, so that’s something like 30,000 metric tonnes! To put that into perspective, the Great Pacific Garbage Patch is said to contain “only” around 80,000 metric tonnes of plastic. Clearly the patch isn’t 37% AOL CDs, but it still gives one pause to consider how many resources AOL put into marketing.

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A Serial Mouse For A Homebrew 8-bit Computer

September 21, 2025 by 2 Comments

[Too Many Wires] has a custom computer he’s building. He wanted a mouse, but USB is a bit of a stretch for the fledgling computer. We might have opted for PS/2, but he went for something even older: a serial mouse connected with a DE-9 (colloquially, a DB-9). Check it out in his recent video update on the project below.

Don’t remember serial mice? They were very common many years ago, and apparently, you can still buy new ones, which makes you wonder what people are doing with them. If you are an old hand at serial, you’ll immediately know why he couldn’t get it to work at first. If you haven’t worked with RS-232 gear before, you’ll learn a lot.

The protocol is simple enough, and you can read the code or find plenty of old documents. He’s using a UART chip, which offloads the CPU. However, the PS/2 mice are very easy to work with directly, and you could skip the +/- 12V RS-232 and other issues.

Either way, however, using an RS-232 or PS/2 mouse in a project is relatively straightforward. You might not think you need a mouse, but don’t forget, they are really accurate two-axis sensors. An optical mouse on a motion table, for example, could be worth something.

The computer is based on [Ben Eater]’s design, if you want more details on that. Can’t decide between RS-232 and PS/2? You don’t have to.

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Two pieces of metal are sitting next to each other on a brick, with one edge touching. The copper end of a torch is directing a flame against the metal, and the metal is glowing brightly around the point where the flame contacts it.

Welding With Natural Gas And Oxygen

September 21, 2025 by 15 Comments

By virtue of its triple bond, acetylene burns hotter than any other common hydrocarbon when mixed with oxygen, but it isn’t the only flame hot enough for welding. With the assistance of a homemade oxygen concentrator, [Hyperspace Pirate] was able to make a natural gas torch that melts steel, even if welding with the torch remains difficult.

[Hyperspace Pirate] built his oxygen concentrator around a pressure-swing adsorption system, which uses two tanks of a molecular sieve to selectively adsorb and purge nitrogen, leaving behind mostly oxygen. [Hyperspace Pirate] used reverse-osmosis membrane casings as the tanks, solenoid valves to control gas flow, and an Arduino with some MOSFETs to control the timing. For fuel, he used a convenient source of natural gas, already installed in his garage: the water heater’s gas supply. Since the house’s meter regulates the gas down to a fairly low pressure, and the oxygen concentrator doesn’t produce high pressures, the torch didn’t need any inline regulators.

Inline check valves, on the other hand, were very much necessary, a mixture of oxygen and natural gas propagating back along the lines being undesirable for obvious reasons, and flashback arrestors would have been a good addition. [Hyperspace Pirate] built the torch itself out of copper tubing and needle valves, with a 0.9 mm MIG welder tip as the nozzle. Adjusting the gas mixture was mostly a matter of trial and error. With an oxygen-rich flame, it could cut thin metal decently well, but it tended to melt thick pieces more than it cut. On the other hand, even with a neutral flame, the water vapor in the exhaust oxidized steel, which made welding quite difficult, but not impossible.

The oxygen supply by itself was an entertaining tool, turning smoldering pieces of charcoal or steel wool violently incandescent. With the assistance of some steel wool, [Hyperspace Pirate] set a steel tube on fire. With a bit more oxygen, it would probably make an effective thermic lance. If you still want to do your welding with acetylene, he’s also made that before.

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DIY electronic eyepiece viewfinder for telescope

Low-Cost, High-Gain: A Smart Electronic Eyepiece For Capturing The Cosmos

September 21, 2025 by 20 Comments

We’ve all seen spectacular pictures of space, and it’s easy to assume that’s how it looks to the naked eye through a nice telescope. But in most cases, that’s simply not true. Space is rather dark, so to make out dim objects, you’ll need to amplify the available light. This can be done with a larger telescope, but that’s an expensive route. Alternatively, you can observe objects for longer periods. This second approach is what [Jordan Blanchard] chose, creating a budget electronic eyepiece for his telescope.

This eyepiece is housed in a 3D printed enclosure designed to fit a standard 1.25″ telescope focuser. The sleek, ergonomic enclosure resembles a night vision device, with a 0.39″ screen for real-time observation of what the camera captures through the telescope. The screen isn’t the only way to view — a USB-C video capture module lets you connect a phone or computer to save images as if you were peering through the viewfinder.

The star of this project is the IMX307 camera module, which supports sense-up mode for 1.2-second exposures and increased gain to capture dim objects without post-processing. This sensor, commonly used in low-light security cameras and dash cams, excels at revealing faint celestial details. All combined, this project cost under 200 Euros, an absolute steal in the often pricey world of astronomy.

Don’t have a telescope? Don’t worry, you can build one of those as well.

For A Robot Claw, The Eyes Have It

September 21, 2025 by 3 Comments

Have you ever wished your hand had an extra feature? Like, maybe, a second thumb? A scope probe pinky maybe? Well, if you are building a robot effector, you get to pick what extra features it has. [Gokux] has the aptly named Cam Claw, which is a 3D printed claw with a built-in camera so you can see exactly what it is doing.

The brains are an ESP32-S3 and the eyes — well, the eye technically — uses an OV3660 camera. There’s even a light in case you are in a dark space. A servo drives it, and the printed gear train is pretty fun to watch, as you can see in the video below.

This project is all about the mechanics. The electronic hardware is trivial. A battery, a power controller, and a servo complement the ESP32 and camera. Six LEDs for light, and the job is done.

Obviously, the gripping power will only be as good as the servo. However, we really liked the idea of putting eyes on a robot hand where they count. Of course, the claw you really want a camera on is in the arcade. We’d like to see cameras on some other robot appendages.

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Building A (Not Very) Portable Xbox

September 21, 2025 by 24 Comments

Modern handheld game consoles are impressive feats of engineering, featuring full fledged computers in near pocket-sized packages. So what happens if you take an original Xbox and sprinkle on some modern electronics and create a handheld? Well, if you’re [James] of James Channel, you end up with this sandwich of PCBs held together with hot glue and duck tape. 

The first order of miniaturization in this Xbox was replacing the hard drive. Because a CompactFlash card uses parallel ATA, that could be a simple drop in replacement. However, the Xbox locks the hard drive to the system requiring a mod chip for the CF card to work. Fortunately, the sacrificial Xbox came with a mod chip installed. After using an arcade machine to flash the card and copy over the contents of the drive, the CF card install was a breeze. 

For the screen and batteries, a portable DVD player that had remained unused since 2006 was repurposed. The battery cells were rather unhappy, but managed to get resurrected with some careful charging. As it turns out, the iPod 30 pin connector inside the portable screen contains an S-Video line. By tapping into that and adding in some power management for the batteries, the Xbox became a pile of PCBs that could maybe be taken places.

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