Elongating A BMX For Drag Racing

February 24, 2026 by No comments

BMX bikes are a unique frame geometry, essentially forgoing all travel efficiency for maneuverability and sturdiness. For how much abuse these bikes are designed to take, these are all good tradeoffs. But it turns out that these bikes also have an exceptionally low center of gravity, which could make them useful for drag racing, provided they’re given a suitably large electric motor and a few minor frame modifications.

The project began as a fun weekend project for friends [Sam Barker] and [Tom Stanton]. They had a 20″ BMX wheel with a massive integrated hub motor that seemed to be begging to be put onto a BMX bike that they had on hand. After hooking up a 72V, 20Ah battery to it they were quickly zipping around the driveway, but the short wheelbase on the bike was bottlenecking its maximum performace because the bike would wheelie under high throttle. To solve that, they broke out the welder and extended frame, which kept the wheelies to a minimum and allowed them to take it out and drag race.

Another benefit to the extended frame is that the bike has room to store its battery now as well; before the frame extension it was strapped to the side of the frame under the rider in a non-ergonomic fashion. The duo also had to figure out a braking solution since the BMX didn’t come with its own brakes, but a loaner caliper from a penny farthing was found for some basic stopping abilities. We might assume this bike is not street legal on many public roads, but not every ebike operates in the same legal jurisdictions you might be the most familiar with.

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Peltier Fridges Have Early Death

February 24, 2026 by 6 Comments

If you know about Peltier modules, a solid-state fridge seems like an easy project. Pump 12V into the module, include a heat sink and a fan. Then you are done, right? According to [Peltier Power], this is not the way to design things, but it is common enough to give these units a reputation for failing quickly.

The problem is that while it makes sense that an inefficient Peltier module needs more power to get more cooling. But the reality is in practical applications, many designs push the current up when it should be moving it down. The curve describes a parabola, and you can be on the high side or low side and still get the same result. But obviously, you don’t want to put in more current and get the same cooling that you could get with lower currents.

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A TV Transmitter From An STM32

February 24, 2026 by 5 Comments

Analog TV may have shuffled off its mortal coil years ago, but there are still plenty of old CRT TV sets around that could receive it. [Kris Slyka] has just such a device, and decided to feed it something from an STM32 microcontroller. An STM32G431, to be precise, and he’s doing it using the on-chip hardware rather than in software.

This unexpected feat is made possible by clever use of the internal oscillators and analog multiplexer. The video itself is generated using the MCU’s DAC, and fed into the on-board op-amp multiplexer which is switched at the VHF transmission frequency. This creates the required VHF TV transmission, but without audio. This component comes by abusing another peripheral, the internal RC oscillator for the USB. This is frequency modulated, and set to the required 5.5 MHz spacing from the vision carrier for the TV in question. It doesn’t (yet) generate the PAL color sub-carrier so for now it’s black and white only, but maybe someone will figure out a way.

We like unexpected out-of-spec uses of parts like these microcontrollers, and we especially like analog TV hereabouts. We marked its very final moments, back in 2021.

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Uni-body That Does The Splits

February 24, 2026 by 1 Comment

Personally, I love a monoblock or uni-body split. You’ll pry this Kinesis Advantage from under my cold, dead hands. But on the go, I really like the Glove 80, a true split that can be completely wireless in case you want to put the halves really far apart.

A triple-black split keyboard without a case, for now.
Image by [thehaikuza] via reddit
[thehaikuza] is the opposite, preferring a full split at the desk, but finding it troublesome when using it on the couch or at a cafe or co-working space, and so created dǎ bāo (打包) — a uni-body split that can also be a distant split. And this best-of-both worlds creation is remarkably [thehaikuza]’s first keyboard.

The name means to take out food, and if you click the picture you can see a cute little take-out container on the silkscreen of the right half. Directly below it, there’s a track point nubbin to be used with the thumb.

It does its split-in-half trick via a magnetic four-pin connector for when you want the halves stuck together. When the halves are separated, they can instead talk over a USB-C cable. One half has the microcontroller, and the other has a GPIO expander.

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Real-time Shader, Running On A Game Boy Color

February 24, 2026 by 2 Comments

[Danny Spencer] has a brilliant graphical demo that, like all great demos, flexes a deep understanding of the underlying system: a real-time 3D shader on the Game Boy Color.

If you’re not familiar with shaders, they were originally mathematical lighting models (hence the name) and are an integral part of the modern 3D graphics pipeline. One no longer draws pixels directly to a screen to represent objects. Instead, 3D object data is sent to the Graphics Processing Unit (GPU) which handles the drawing. Shaders are what control things like an object’s lighting, textures, and more.

Implementing even a basic real-time shader in software on a Game Boy Color is pretty wild. Not only is it a pixels-and-sprites (and not 3D graphics) kind of system, but the Game Boy’s SM83 CPU doesn’t even have a multiply instruction, nor does it support floats. As [Danny] puts it: given that the entire mathematical foundation of his shader rests on multiplying non-integer numbers, he had to get creative. That makes his demo a very round peg in an extremely square hole.

In the case of [Danny]’s demo, the user can manipulate the position of, and lighting around, a classic Utah teapot in real time. He explains the workflow and shows how the process can be applied to other objects. The ROM is available on GitHub and there’s a video, embedded below.

[Danny] is no stranger to performing feats of technical prowess that are as creative as they are playful, like implementing a working adding machine in a DOOM level.

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Railguns: Making Metal Go Fast Using The Lorentz Force

February 24, 2026 by 15 Comments

In science fiction, the use of gunpowder-based weapons is generally portrayed as something from a savage past, with technology having long since moved on to more civilized types of destructive weaponry, involving lasers, microwaves, and electromagnetism. Instead of messy detonating powder, energy-weapons are used to near-instantly deposit significant amounts of energy into the target, and railguns enable the delivery of projectiles at many times the speed of sound using nothing but the raw power of electricity and some creative physics.

Of course, the reason that we don’t see sci-fi weapons deployed everywhere has arguably less to do with today’s levels of savagery in geopolitics and more with the fact that physical reality is a very harsh mistress, who strongly frowns upon such flights of fancy.

Similarly, the Lorentz force that underlies railguns is extremely simple and effective, but scaled up to weapons-grade dimensions results in highly destructive forces that demolish the metal rails and other components of the railgun after only a few firings. Will we ever be able to fix these problems, or are railguns and similar sci-fi weapons forever beyond our grasp?

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The Challenges Of Simulating A Human Brain On A Supercomputer

February 24, 2026 by 18 Comments

It’s quite the understatement to say that at this point in time we don’t quite understand how even the tiniest brain works exactly. Much of this is due to the sheer complexity and scale of these little biological marvels: with the human brain packing billions of neurons and their associated supportive scaffolding into a few kilograms of gooey pink-white mass, the sheer connectivity density is more than we can reasonably hope to measure in-situ. Ergo attempts to recreate digital simulations of small sections of such brains, a process that’s making gradual progress.

Most recently we have been doing mapping of neurons and their connections in the brain of the humble fruitfly, D. melanogaster. Despite their brains being minuscule, with only about 140,000 neurons and 50 million connections, we’re not quite at the level where we can have a simulated fruitfly brain spark to life. This should probably give us some hints as to the sheer complexity of mapping the human brain, never mind simulating even a small part like a cubic millimeter of the temporal cortex with about 57,000 cells and 150 million synapses.

Even once you have all the connectome data of such a bit of brain, it’s not like you can just toss it onto a supercomputer and expect a meaningful simulation. All supercomputers today are massively parallel, meaning thousands of networked computers that require the computing task to be split up and all communication between nodes restricted as much as possible to not starve nodes.

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