Restoring A Vintage Computer And Its Plotter

September 22, 2025 by 23 Comments

Repairing vintage computers is bread-and-butter for many of us around here. The machines themselves tend to be fairly fixable, assuming spare parts are available and there hasn’t been too much physical damage. Peripherals can be another matter, though. Since they interface with the real world they can have more esoteric problems that aren’t always solvable. [joekutz] was handed just such a device in the form of a CE-150 docking station for a Sharp PC1500 Pocket Computer, which has a plotter built in. Here’s his “tip” for getting plotters like these working again.

The first step here is to disassemble the original, dried out pens to scavenge a few of the parts. The outer case needs to be kept so that it can be put back into the plotter, and a small O-ring is saved as well. To replace the dried-out tips [joekutz] discards the original tips and replaces them with tips from a common ink pen, using shrink wrap tubing to help fit the pen’s tip into the original plotter cylinder. He also takes the ink from the pen to fill the plotter’s cartridge, completing the surgery on the multi-colored plotter and bringing it back to life.

Of course this build goes well beyond the plotter, including bringing the PC1500 back to life as well. There are a few other videos about this project covering that original restoration as well as demonstrating some of the quirks of how this computer is meant to be programmed. But we mostly focused on the plotter here since that is a little bit out of the ordinary, and we’re also sure that refilling ink cartridges of any sort gets under the skin of everyone at HP.

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Mandrel Magic: Small Box Assembly With 3D Printing

September 21, 2025 by 2 Comments

Often, we face tedious tasks with no way around them. Sometimes, you just have to grit your teeth and push through. But small tweaks can make the onerous task a bit easier to handle. [James Bowman] sent in his latest quick project that helps him fold small boxes more efficiently.

To fulfill orders on his previously covered TermDriver2, [James Bowman] is faced with folding thousands of small boxes. To aid in this daunting task, he had the idea of making a tool to streamline the process — every second saved adds up when you’re repeating a task thousands of times. He designed a 3D printed mandrel that pops the flat box blank open as it’s slid over the tapered top, shaping it into a perfect rectangle for easy folding of the top flaps.

The nice thing about 3D printng is how easy it is to iterate on a design. Once James had the first version printed and verified it worked as hoped, he had ideas to improve it, such as adding a second mandrel to twist the box from both the inside and outside and adding a guide on one side to enhance rigidity.

While we often think of 3D printers producing ready-to-use parts, but printed tooling holds great potential for repetitive tasks, and is a huge cost saver compared to traditional methods.

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 18 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.