TechyMagThings

A problem facing the designers of event badges is this: what happens to the badge after the event? It’s one that designers have tried to solve in many ways with varying levels of success, whether that be by making it a dev board, a games console, a mesh-networked communicator, or as in the case of Electromagnetic Field, a continuing badge for future events. Ar BornHack 2026 they have taken a novel approach, by making it a useful desktop appliance. The BornHack Cyber Ægg is a half-egg-shaped badge with a 3D-printed case, and aside from its on-camp applications it’s both a desktop clock/calendar, and a MeshCore node.

Produced with the assistance of the badge.team European badge makers, it’s an egg-shaped PCB with a Nordic nRF52840 at its heart, a Semtech LoRa module, and an e-paper display. On-site there’s a Tamagotchi-style virtual pet game, an event calender, and an RFID token game, but it’s the other two features that give it a life after the camp. The clock and Meshcore, coupled with its case being designed with a flat spot to sit on a desk, make this badge as much an appliance as it is a badge. This is where it will sit in the Hackaday office, and we’re pretty sure most BornHack attendees will use it thus too.

We like this approach to giving a badge a life after the event, and we look forward to seeing what influence it has on future badges. A badge should be a thing to enjoy, not a piece of e-waste.

In 1675, while transporting a barometer by night, the astronomer Jean Picard noticed a glow inside its glass tube, just above the mercury. As the mercury sloshed and splashed across the surface of the glass, a static electric charge had built up, which was discharging by ionizing the residual gas molecules inside the evacuated tube. [Styropyro] recreated this effect, and found that the dim glow could be made much stronger by adding some noble gas to the tube.

It starts with a simple recreation: he took a volumetric flask, attached a narrow glass stem to the mouth, added some mercury to the flask, evacuated it with a vacuum pump, and sealed off the glass stem. This produced a faint glow when shaken, but it was only really visible under very low light. When [Styropyro] brought it near a Tesla coil, however, it did glow much more brightly.

Backfilling an identical flask with neon to about 40 millitorr produced a much more spectacular result (a low pressure in the tube is necessary, but moderate pressure variations don’t significantly alter the effect). When shaken even slightly, this neon-containing flask produced a bright orange-red glow just above the surface of the mercury. Points of obstruction, such as those in a zig-zag tube, produced a brighter glow. A krypton-containing tube glowed blue, but less brightly than the neon tube.

Since this is, essentially, a triboelectric effect, other materials besides mercury should work; [Styropyro] tested several materials, and found that pieces of Teflon produced a faint glow, and copper beads a somewhat brighter glow. Unfortunately, Galinstan, the obvious replacement for mercury, wets and coats glass, preventing a charge buildup.

Without an added noble gas, the standard glow of barometric light comes from the excitation of mercury vapors, a glow which can also be seen in mercury rectifiers, and which excites the phosphors of fluorescent light bulbs.

Thanks to [Vik Olliver] for the tip!

Railroads might be a nineteenth century technology, but they’re still the backbone of cargo transportation in the 21st century. They’ve also far from run out of innovation, including this one which really just sounds like a hack: painting the rails white to beat the heat.

In the old days, when rails were short and riveted together, this might have been unecesssary; all those joints allowed for a lot of flex. But when you have kilometers of continously welded rail, the thermal expansion starts to matter. A lot. Even if the rails haven’t bent and buckled from excess heat, their capacity goes down. Trains must therefore slow way, way down in hot weather, reducing the overall amount of freight the system can handle.

So, how do you cool the million miles of metal that holds a country together? Paint. Simple white paint sprayed on the side of the rails can bring down temperatures 11 °C (20 °F), according to the Union Pacific Railroad, the first to try this in North America. It might not surprise you that this technique is also being rolled out on the other side of the pond during this summer’s European heat waves. Indeed, it was invented there; the Italians have been doing it for many years now.

If you think reducing solar heat with white paint is good, you can do better than that with special formulations that end up cooler than ambient. It passive cooling also comes in fibre form.

[Dr. Gough] bought a generic USB 3.0 hub on an Asian website. Surely, USB 3 is mature enough that even the cheapest hub will have some IC in it that will work well, right? You’d think so, but a little exploratory surgery showed that the only thing about this hub that was USB 3 were the blue port connectors.

We have a few problem USB hubs ourselves, so it might be worth doing this to any you have lying around. The first clue: most of the connectors on the PCB only have four pins. On closer examination, the hub appears to be a USB 3.0 extension cable with a USB 2.0 hub made from two HS8836A chips.

Not only are these USB 2-only, but all the ports on an HS8836A also share the same USB 1.1 bandwidth. Some hubs can provide multiple ports full 1.1 bandwidth, using the higher-speed USB protocol to the PC as a backhaul.

There were quite a few other issues. Missing solder, cables soldered to the board directly, and no bypass capacitors. The per-port switches cut off USB power, but that wouldn’t stop a device with its own power from connecting. The hub has a barrel jack for power, but it would feed back to the PC, which is bad practice at best.

If you use Linux, try lsusb -t and look at the negotiated speed for your hubs. If they aren’t what you expect, it could be a cable issue, or it could just be that you also have a cheap USB hub. Don’t be surprised if your USB 3 hub shows both a USB 3 and a USB 2 hub; that’s common. But if you only see the USB 2 hub, something is amiss, or someone’s lying.

You can learn a lot about USB 3 reading Hackaday.

CD+Graphics was a format that never really caught on. It let music discs pack some graphics, maybe liner notes, and mostly song lyrics into the otherwise empty space on a CD. It was never intended for displaying full-motion video, but that didn’t stop [Adam Gashlin] from getting a Bad Apple, with lyrics, running on any device that will play CD+G.

The main challenge is that CD+G gives you 300 screen commands per second, which is plenty for updating text on the 48×16 blocks as the lyrics scroll by. But if you want to send custom blocks and draw images, that’s 2.5 seconds per screen: a lousy framerate.

[Adam]’s first trick is to drop the resolution way down, which gets him into the 8 FPS range. Only update the blocks that change pushes this up to a respectable 17-20 FPS. But you can see the updates, and that’s distracting. It really needed buffering.

If you don’t know Bad Apple, it’s in black and white. And like many old graphics engines of the day, CD+G uses a dynamic palette of colors. [Adam] uses this to pack four frames into one, switching between them using palette swapping. (Absolutely check out his “rainbow” version of the video to see how the palette-swapping trick works.)

In the end, his demo has audio, triple-buffered video, and lyrics at 16.3 FPS. It’s slower than the fastest video-only version, but it looks so good, and [Adam]’s explanation of all of the graphics tricks he uses to get there is the real star of the show.

If you want to see Bad Apple running on yet more minimal hardware, how about a 16×2 LCD? Or a much more ridiculous implementation? How’s regexes in Vim for absurd? Got any Bad Apple hacks of your own? Let us know in the comments or the tips line. You can never have too many.

Compared to the Arduino Uno of old, modern microcontrollers are absolutely tiny — especially for the amount of processing power and I/O you get. But if you need something really small, like fits-on-the-tip-of-your-finger small, most of the turn-key development boards on the market are still a bit too big.

Enter the pinch from moddo, which they advertise as “The World’s Smallest 32-Bit Arduino-
Compatible Board.” We can’t vouch for its world-record status, but we certainly can’t think of a smaller one. At least not a complete solution like this, which offers native USB and 15 GPIO pins in addition to the usual suspects like SPI, I2C, PWM, and UART. In fact, it’s so small that it even includes a breakout board to make prototyping a bit easier.

Coming from something like an ESP32, the biggest adjustment will probably be working around the relatively limited specs of the SAMD11. The ARM Cortex-M0+ under the hood tops out at 48 MHz, and there’s only 4 KB SRAM and 16 KB flash (of which the bootloader eats up 4 KB). Still, not bad for something that occupies roughly the same surface area as a female USB-C connector.

We’re told the team is in the final stages of testing and production of the pinch, and you can currently pre-order the $16 board ahead of its planned September ship date. A circuit schematic and STEP 3D model are already available, and it looks like board design files aren’t far behind.

Just when you thought we’d run out of things to port DOOM to, here comes [Ahmed Amer] with his CSS-DOS, a massive 300 MB CSS style sheet, that runs not just DOS, but Windows 1.0 and, of course, DOOM. The CSS sheet isn’t holding a DOOM port this time, though — it’s holding a full IBM PC compatible, with a simulated 8086, 640 kB of RAM, floppy and VGA controllers. Yes, in one style sheet. We did mention it was 300 MB, right?

CSS is not a very good programming language. It’s got functions and if statements nowadays, but it doesn’t really do programs in the usual sense. That is, lists of instructions that feed one into another. You can’t change a variable without jumping through hoops. The sort of static behavior you get from a CSS sheet actually matches hardware architecture better than software, which was the key insight [Ahmed] had to make the project possible. It’s still not easy, or elegant, or perhaps even sane, as you can find out from the excellent write-up he has describing how he pulled this off. We particularly like the interactive guide to the full mountain of madness that is the .css file.

Now, we admit that “runs DOOM” may be an exaggeration — even if the maddeningly massive CSS sheet ran an IBM-AT full speed, that hardware can’t handle the game at any playable speed. It doesn’t emulate at anything close to full speed, though. Because this is such a gratuitously weird hack, it only runs at two instructions per second. No, not FPS, instructions, as in at the CPU level. Well, it could be worse, at least it’s not clock ticks. Still, if you’re time-dilated enough you can wait the 3 weeks to boot DOS, and the 3 months to load a level, you can play DOOM at 0.0001 FPS.

Look, we didn’t make the rules — they say everything has to try and run DOOM. They don’t say everything has to run it well.