2025 Component Abuse Challenge: Glowing Neon From A 9 V Relay

November 8, 2025 by Jenny List 7 Comments

Most of us know that a neon bulb requires a significant voltage to strike, in the region of 100 volts. There are plenty of circuits to make that voltage from a lower supply, should you wish to have that comforting glow of old, but perhaps one of the simplest comes from [meinsamayhun]. The neon is lit from a 9-volt battery, and the only other component is a relay.

What’s going on? It’s a simple mechanical version of a boost converter, with the relay wired as a buzzer. On each “off” cycle, the magnetic field in the coil collapses, and instead of being harvested by a diode as with a boost converter, it lights the neon. Presumably, the neon also saves the relay contacts from too much wear.

We like this project for its simplicity and for managing to do something useful without a semiconductor or vacuum tube in sight. It’s the very spirit of our 2025 Component Abuse Challenge, for which there is barely time to enter yourself if you have something in mind.

What Has 5,000 Batteries And Floats?

November 8, 2025 by Al Williams 52 Comments

While it sounds like the start of a joke, Australian shipmaker Incat Tasmania isn’t kidding around about electric ships. Hull 096 has started charging, although it has only 85% of the over 5,000 lithium-ion batteries it will have when complete. The ship has a 40 megawatt-hour storage system with 12 banks of batteries, each consisting of 418 modules for a total of 5,016 cells. [Vannessa Bates Ramierz] breaks it down in a recent post over on IEEE Spectrum. You can get an eyeful of the beast in the official launch video, below. The Incat Tasmania channel also has other videos about the ship.

The batteries use no racks to save weight. Good thing since they already weigh in at 250 tonnes. Of course, cooling is a problem, too. Each module has a fan, and special techniques prevent one hot cell from spreading. Charging in Australia comes from a grid running 100% renewable energy. When the ship enters service as a ferry between Argentina and Uruguay, a 40-minute charge will be different. Currently, Uruguay has about 92% of its power from renewable sources. Argentina still uses mostly natural gas, but 42% of its electricity is sourced from renewable generation.

The ship is 130 meters (426 feet) long, mostly aluminum, and has a reported capacity of 2,100 people and 225 vehicles per trip. Ferry service is perfect for electric ships — the distance is short, and it’s easy to schedule time to charge. Like all electric vehicles, though, the batteries won’t stay at full capacity for long. Typical ship design calls for a 20-year service life, and it’s not uncommon for a vessel to remain in service for 30 or even 40 years. But experts expect the batteries on the ferry will need to be replaced every 5 to 10 years.

While electric ferries may become common, we don’t expect to see electric cargo ships plying the ocean soon. Diesel is hard to beat for compact storage and high energy density. There are a few examples of cargo ships using electric, though. Of course, that doesn’t mean you can’t build your own electric watercraft.

Continue reading “What Has 5,000 Batteries And Floats?” →

BIOS Detectives Find Ghost Of Previously Unknown PC

November 8, 2025 by Jenny List 20 Comments

Old parts such as EPROMs will often find themselves for sale on sites such as eBay, where they are sometimes snapped up by retrocomputing enthusiasts in search of interesting code. Vintage Computer Federation forum member [GearTechWolf] picked up a clutch of IBM-labelled chips, and as int10h reports, stumbled upon a previously unknown PC-AT BIOS version which even hints at a rare PC model as yet unseen.

The IBM AT and its various versions are extremely well known in the retro PC world, so while this was quickly identified as an IBM BIOS from 1985 and narrowed down to a member of the AT family, it didn’t fit any of the known versions which shipped with the ubiquitous 1980s computer. Could it have been from an industrial or rack mount variant? It’s a possibility, but the conclusion is that it might contain a patched BIOS version of some kind.

Lacking real hardware, it happily boots on an emulator. It’s another piece of the PC historical jigsaw for people interested in computer history, and with luck in time someone will unearth an example of whatever it came from. If you find it, try a modern OS on it!

A photo of a hand holding the inductor coil

2025 Component Abuse Challenge: Using Inductors To Steal Power From Qi Wireless Charging Base Station

November 7, 2025 by John Elliot V 1 Comment

Over on Hackaday.IO our hacker [bornach] has his entry into the Component Abuse Challenge: Inductors are Wireless Power Sources.

Some time back [bornach] was gifted a Qi wireless charging base station but didn’t own any compatible devices. He had a dig around in his junk box for inductors to attempt coupling to the wireless charger and lucked out with an inductor salvaged from his old inkjet printer.

There are actually open standards, known as the Qi standards, for how to negotiate power from a Qi device. But [bornach] ignored all of that. Instead he leveraged the fact that the Qi base station will periodically send out a “ping” containing a small measure of power to let compatible devices know that it’s available for negotiation. It is the energy in this “ping” that power’s [bornach]’s circuit!

In [bornach]’s circuit a TL431 provides a regulated five volt supply which can be used to drive a microcontroller and a charliplexed array of ten LEDs. Pretty nifty stuff. If you’re new to wireless charging you might like to know How Wireless Charging Works And Why It’s Terrible. Continue reading “2025 Component Abuse Challenge: Using Inductors To Steal Power From Qi Wireless Charging Base Station” →

OldVersion.com Archive Facing Shutdown Due To Financing Issues

November 7, 2025 by Maya Posch 17 Comments

Finding older versions of particular software can be a real chore, all too often only made possible by the sheer grace and benevolence of their creators. At the same time older versions of software can be the only way to dodge undesirable ‘upgrades’, track down regressions, do historical research, set up a retro computer system, and so on. This is where an archive like OldVersion.com (HTTP only so your browser may shout at you) is incredibly useful, offering thousands of installers for software covering a number of platforms.

Unfortunately, as noted on the website, they recently lost their main source of income in the form of Google advertising. This means that after launching in 2001, this archive may soon have to be shut down before long. Confusingly, trying to visit the blog throws a HTTP 503 error, and visiting the forum currently forces a redirect to a random news site unless you can mash that Esc button really fast, perhaps as alternative advertising partners are being trialed, or due to a hack.

Although these days we have sites like Archive.org to do more large scale archiving, OldVersion.com is special for being focused and well-organized, along with a long and rich history that would be a shame to lose. We have referenced the site in the past for old versions as far back as 2008. Hopefully we’ll soon find out more about what is going on with the archive and what its future will be.

Thanks to [Philip Perry] for the tip.

Screen-Accurate Lightsaber As A Practical Effect

November 7, 2025 by Tyler August 17 Comments

The lightsaber was one of the coolest and most iconic visual effects from the original Star Wars, and people have been trying to get that particular piece of movie magic off the silver screen for about 40 years now. [HeroTech] seems to have cracked the code with their “Impossible Lightsaber”— it’s fully retractable, fully lit, and able to hit things (lightly), all while fitting into a replica prop handle.

The secret is… well, there’s more than one secret, here. The blade itself is made out of a “magician’s cane”, which is a coil of plastic that can spring outwards on demand for magic tricks. Hidden inside of it is a strip of LED lights. Of course one strip of LEDs would not be omnidirectional, and the magician’s cane is pretty floppy, but both of those problems are solved by the same idea: “I’ll try spinning. That’s a good trick.”

The spin-stabilized blade holds up to being waved around much better, and apparently the gyroscopic forces it induces are actually lore-accurate. (Who knew?) Of course fitting a motor to spin the “blade”, and another to winch it back in, along with the circuitry and batteries to drive them was no mean feat. It’s impressive they fit it all inside the replica handle; even more impressive that they fit a speaker so this prop even makes the iconic sound effects. We always wanted to see a stage production of William Shakespeare’s Star Wars, and this gives us verily, a new hope.

[HeroTech] isn’t done yet– while seemingly impossible, this lightsaber isn’t perfect, as it’s not rugged enough for full dueling. It’s also not easy to put together, and apparently can’t handle the delicate attentions of airline baggage handlers. So ruggedization and a bit of design-for-assembly are on the table for the next version. Sadly the project is not open source; they are releasing the build files to subscribers only. Given how much work must have gone into iterating to get to this point, that is disappointing, but understandable. Everybody needs to make a living, after all.

If this project seems familiar, it’s because we featured a much-bulkier previous iteration last year.

You may prefer your lightsabers to match the movie version in effects instead of visuals; if that’s the case, check out this saber that uses HHO to cut through a steel door.

Continue reading “Screen-Accurate Lightsaber As A Practical Effect” →