Author: Dan Maloney

3273 Articles

Got Junk? Then Build This Scrappy TEA Laser

March 13, 2025 by 24 Comments

A piece of glass, some bits of tinfoil, a sheet of plastic, a couple of razor blades, and a few assorted bits and bobs are all it takes to build this TEA nitrogen laser. Oh, and a 5,000-volt flyback supply with enough amperage to stop your heart. You’ll need that too.

Seriously, if you choose to follow [MultiverseCurator] ‘s example and build this laser, you’ll want to take the proper precautions. A transversely excited atmospheric laser is simple in concept, but there are plenty of ways for them to go wrong. Unlike the gas lasers used in laser cutters, there’s no enclosed resonator cavity or mirrors. Rather, the excitation takes place across a narrow gap between two electrodes, using atmospheric nitrogen as the lasing medium. This results in hard UV emissions, which means you can’t see them with the naked eye. Add to that the spark gap creating extremely loud discharges as the laser operates, and hazards abound. Proceed with caution.

Construction starts with a flat glass plate and a pair of large capacitors made from aluminum foil plates separated by a plastic dielectric. The razor blades are connected across the capacitors, separated by a narrow gap, with an inductor made from magnet wire in parallel. A spark gap made from nuts and bolts goes in series, and the whole assembly gets connected to a high-voltage power supply — [Multiverse] used a ZVS driver and a CRT flyback transformer with an eight-megohm resistor in series. The video below has all the build details.

It’ll take a little fiddling to get it lasing, and you’ll need something phosphorescent to see the UV light — a scrap of copy paper should do. But the results are pretty amazing for something made from scrap. If you want to take the design to the next level, you’ll want to check out [Les Wright]’s TEA laser build.

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Classy Paper Tape Reader Complements Homebrew Retrocomputer

March 11, 2025 by 26 Comments

If you were one of the earliest of early adopters in the home computing revolution, you might have had to settle for paper tape mass storage. It was slow, it was bulky, but it was what you had, and that gave it a certain charm that’s hard to resist. And that charm is what [Joshua Coleman] captures with this DIY paper tape reader build.

If the overall style of this project looks familiar, it’s because it was meant to echo the design themes from [Joshua]’s Coleman Z-80 modular computer. The electronics of the reader are based on [David Hansel]’s take on a paper tape reader, which in turn was meant to complement his Altair 8080 simulator — it’s retrocomputers all the way down! [Joshua]’s build has a few bells and whistles to set it apart, though, including an adjustable read head, parametric 3D-printed reels, and a panel mounted ammeter, just because. He also set it up to be a sort of keyboard wedge thanks to an internal relay that bypasses the reader unless it’s actually playing back a tape. Playback speed is pretty fast; see the video below for details.

So far, writing the tapes is an offline process. [Joshua] uses a Python program to convert ASCII to an SVG file and uses a laser cutter to burn holes in lengths of paper, which are then connected together to form a longer tape. A logical next step might be to build a feeder that moves a paper tape across the bed of the laser cutter in sync with the conversion program, to create continuous paper tapes. Or, there’s always the old-school route of solenoid-powered punch and die. We’d be thrilled with either.

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Tiny Laptop Gets A New Case And An Unlocking

March 11, 2025 by 21 Comments

Unless you’ve got an especially small lap, calling the Toshiba Libretto a laptop is a bit of a stretch. The diminutive computers from the mid-1990s had a lot of the usual laptop features, but in an especially compact and portable case that made them a great choice for anyone with an on-the-go lifestyle.

Fast-forward thirty years or so, and the remaining Librettos haven’t fared too well. Many of them have cases that crumble at the slightest touch, which is what led [polymatt] to undertake this meticulous case replacement. The effort started with a complete teardown; luckily, the lower aluminum-alloy shell was in fine shape, but the upper case parts were found to be almost too deteriorated to handle. Still, with a little patience and the judicious application of tape, [polymatt] was able to scan the case pieces on a flatbed scanner and import them into his CAD package. Great tip on the blue-tack for leveling the parts for accurate scanning, by the way.

After multiple rounds of printing and tweaking, [polymatt] had a case good enough to reassemble the Libretto. Unfortunately, the previous owner left an unwanted gift: a BIOS password. Disconnecting the CMOS battery didn’t reset it, but a little research told him that shorting a few pins on the parallel port on the machine’s dock should do the trick. It was a bit involved, requiring the design and subsequent bodging of a PCB to fit into the docking port connector, but in the end he was able to wake up a machine to all its Windows 95 glory. Better get patching.

In a time when laptops were more like lap-crushers, the Libretto was an amazing little machine, and thirty years on, they’re well worth saving from the scrap heap. Hats off to [polymatt] for the effort to save this beauty, and if he needs tips on reading data from any PCMCIA cards that may have come with it, we’ve got him covered.

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Hackaday Links: March 9, 2025

March 9, 2025 by 9 Comments

It’s been a busy week in space news, and very little of it was good. We’ll start with the one winner of the week, Firefly’s Blue Ghost Mission 1, which landed successfully on the Moon’s surface on March 2. The lander is part of NASA’s Commercial Lunar Payload Services program and carries ten scientific payloads, including a GPS/GNSS receiver that successfully tracked signals from Earth-orbiting satellites. All of the scientific payloads have completed their missions, which is good because the lander isn’t designed to withstand the long, cold lunar night only a few days away. The landing makes Firefly the first commercial outfit to successfully soft-land something on the Moon, and being the first at anything is always a big deal.

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Retrotechtacular: Better Living Through Nuclear Chemistry

March 8, 2025 by 11 Comments

The late 1950s were such an optimistic time in America. World War II had been over for less than a decade, the economy boomed thanks to pent-up demand after years of privation, and everyone was having babies — so many babies. The sky was the limit, especially with new technologies that promised a future filled with miracles, including abundant nuclear power that would be “too cheap to meter.”

It didn’t quite turn out that way, of course, but the whole “Atoms for Peace” thing did provide the foundation for a lot of innovations that we still benefit from to this day. This 1958 film on “The Armour Research Reactor” details the construction and operation of the world’s first privately owned research reactor. Built at the Illinois Institute of Technology by Atomics International, the reactor was a 50,000-watt aqueous-homogenous design using a solution of uranyl sulfate in distilled water as its fuel. The core is tiny, about a foot in diameter, and assembled by hand right in front of the camera. The stainless steel sphere is filled with 90 feet (27 meters) of stainless tubing to circulate cooling water through the core. Machined graphite reflector blocks surrounded the core and its fuel overflow tank (!) before the reactor was installed in “biological shielding” made from super-dense iron ore concrete with walls 5 feet (1.5 m) thick — just a few of the many advanced safety precautions taken “to ensure completely safe operation in densely populated areas.”

While the reactor design is interesting enough, the control panels and instrumentation are what really caught our eye. The Fallout vibe is strong, including the fact that the controls are all right in the room with the reactor. This allows technicians equipped with their Cutie Pie meters to insert samples into irradiation tubes, some of which penetrate directly into the heart of the core, where neutron flux is highest. Experiments included the creation of radioactive organic compounds for polymer research, radiation hardening of those new-fangled transistors, and manufacturing radionuclides for the diagnosis and treatment of diseases.

This mid-century technological gem might look a little sketchy to modern eyes, but the Armour Research Reactor had a long career. It was in operation until 1967 and decommissioned in 1972, and similar reactors were installed in universities and private facilities all over the world. Most of them are gone now, though, with only five aqueous-homogenous reactors left operating today.

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Get Into Meshtastic On The Cheap With This Tiny Node Kit

March 8, 2025 by 14 Comments

There’s been a lot of buzz about Meshtastic lately, and with good reason. The low-power LoRa-based network has a ton of interesting use cases, and as with any mesh network, the more nodes there are, the better it works for everyone. That’s why we’re excited by this super-affordable Meshtastic kit that lets you get a node on the air for about ten bucks.

The diminutive kit, which consists of a microcontroller and a LoRa module, has actually been available from the usual outlets for a while. But [concretedog] has been deep in the Meshtastic weeds lately, and decided to review its pros and cons. Setup starts with flashing Meshtastic to the XIAO ESP32-S3 microcontroller and connecting the included BLE antenna. After that, the Wio-SX1262 LoRa module is snapped to the microcontroller board via surface-mount connectors, and a separate LoRa antenna is connected. Flash the firmware (this combo is supported by the official web flasher), and you’re good to go.

What do you do with your new node? That’s largely up to you, of course. Most Meshtastic users seem content to send encrypted text messages back and forth, but as our own [Jonathan Bennett] notes, a Meshtastic network could be extremely useful for emergency preparedness. Build a few of these nodes, slap them in a 3D printed box, distribute them to willing neighbors, and suddenly you’ve got a way to keep connected in an emergency, no license required.

Trio Of Mods Makes Delta Printer More Responsive, Easier To Use

March 7, 2025 by 9 Comments

Just about any 3D printer can be satisfying to watch as it works, but delta-style printers are especially hypnotic. There’s just something about the way that three linear motions add up to all kinds of complex shapes; it’s mesmerizing. Deltas aren’t without their problems, though, which led [Bruno Schwander] to undertake a trio of interesting mods on his Anycubic Kossel.

First up was an effort to reduce the mass of the business end of the printer, which can help positional accuracy and repeatability. This started with replacing the stock hot-end with a smaller, lighter MQ Mozzie, but that led to cooling problems that [Bruno] addressed with a ridiculously overpowered brushless hairdryer fan. The fan expects a 0 to 5-VDC signal for the BLDC controller, which meant he had to build an adapter to allow Marlin’s 12-volt PWM signal to control the fan.

Once the beast of a fan was tamed, [Bruno] came up with a clever remote mount for it. A 3D-printed shroud allowed him to mount the fan and adapter to the frame of the printer, with a flexible duct connecting it to the hot-end. The duct is made from lightweight nylon fabric with elastic material sewn into it to keep it from taut as the printhead moves around, looking a bit like an elephant’s trunk.

Finally, to solve his pet peeve of setting up and using the stock Z-probe, [Bruno] turned the entire print bed into a strain-gauge sensor. This took some doing, which the blog post details nicely, but it required building a composite spacer ring for the glass print bed to mount twelve strain gauges that are read by the venerable HX711 amplifier and an Arduino, which sends a signal to Marlin when the head touches the bed. The video below shows it and the remote fan in action.

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