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

Keebin’ With Kristina: The One With The Leather Keyboard

March 31, 2025 by Kristina Panos 13 Comments

Are you eager to get your feet wet in the keyboard surf, but not quite ready to stand up and ride the waves of designing a full-size board? You should paddle out with a macro pad instead, and take on the foam face-first and lying down.

A beautiful purple galaxy-themed macro pad with nine switches and three knobs. — Image by [Robert Feranec] via Hackaday.IO

Luckily, you have a great instructor in [Robert Feranec]. In a series of hour-long videos, [Robert] guides you step by step through each part of the process, from drawing the schematic, to designing a PCB and enclosure, to actually putting the thing together and entering a new world of macros and knobs and enhanced productivity.

Naturally, the fewer keys and things you want, the easier it will be to build. But [Robert] is using the versatile Raspberry Pi 2040, which has plenty of I/O pins if you want to expand on his basic plan. Not ready to watch the videos? You can see the schematic and the 3D files on GitHub.

As [Robert] says, this is a great opportunity to learn many skills at once, while ending up with something terrifically useful that could potentially live on your desk from then on. And who knows where that could lead?

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DIY Linear Tubular Motor Does Precise Slides

March 31, 2025 by Donald Papp 25 Comments

We’ve seen plenty of motor projects, but [Jeremy]’s DIY Tubular Linear Motor is a really neat variety of stepper motor in a format we certainly don’t see every day. It started as a design experiment in making a DIY reduced noise, gearless actuator and you can see the result here.

Here’s how it works: the cylindrical section contains permanent magnets, and it slides back and forth through the center of a row of coils depending on how those coils are energized. In a way, it’s what one would get by unrolling a typical rotary stepper motor. The result is a gearless (and very quiet) linear actuator that controls like a stepper motor.

While a tubular linear motor is at its heart a pretty straightforward concept, [Jeremy] found very little information on how to actually go about making one from scratch. [Jeremy] acknowledges he’s no expert when it comes to motor design or assembly, but he didn’t let that stop him from iterating on the concept (which included figuring out optimal coil design and magnet spacing and orientation) until he was satisfied. We love to see this kind of learning process centered around exploring an idea.

We’ve seen DIY linear motors embedded in PCBs and even seen them pressed into service as model train tracks, but this is the first time we can recall seeing a tubular format.

Watch it in action in the short video embedded below, and dive into the project log that describes how it works for added detail.

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Tiny Bubbles In The Memory

March 31, 2025 by Al Williams 15 Comments

We are always fascinated by bubble memory. In the late 1970s, this was the “Next Big Thing” that, as you may have guessed, was, in fact, not the next big thing at all. But there were a number of products that used it as non-volatile memory at a time when the alternative was tape or disk. [Smbakeryt] has a cool word processor with an acoustic coupler modem made by Teleram. Inside is — you guessed it — bubble memory.

The keyboard was nonfunctional, but fixable. Although we wouldn’t have guessed the problem. Bubble memory was quite high tech. It used magnetic domains circulating on a thin film of magnetic material. Under the influence of a driving field, the bubbles would march past a read-write head that could create, destroy, or read the state of the bubble.

Why didn’t it succeed? Well, hard drives got cheap and fairly rugged. The technology couldn’t compete with the high-density hard drives that could be reached with improved heads and recording strategies. Bubble memory did find use in high-vibration items, but also wound up in things like this terminal, at least one oscilloscope, and a video game.

Bubble memory evolved from twistor memory, one of several pre-disk technologies. While they are hard to come by today, you can find the occasional project that either uses some surplus or steals a part off of a device like this one.

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