Electromechanical 7-Segment Display Is High Contrast Brilliance

January 13, 2025 by 11 Comments

The seven-segment display is most well known in LED form, but the concept isn’t tied to that format. You can build a seven-segment display out of moving parts, too. [tin-foil-hat] has achieved just that with a remarkably elegant design.

As you might expect, the build relies heavily on 3D-printed components—produced in white and black plastic to create a high-contrast display. It’s a simple choice that makes the display easy to read in a wide variety of lighting conditions, and far less fussy than toying with LEDs and diffusers and all that.

Actuation of each display segment is achieved electromagnetically. Effectively, each segment behaves like a flip dot, with the orientation controlled by energizing one of two electromagnets per segment. Controlling the electromagnets is an ESP32, which is hooked up to the various segments via a Darlington transistor array, with multiplexing used to minimize the number of IO pins required. A shift register was also employed to let the microcontroller easily drive four of these electromechanical digits.

It’s a simple build, well explained—and the final result is aesthetically pleasing. We’ve seen a few builds along these lines before, albeit using altogether different techniques. Lots of different techniques, in fact! Video after the break.

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Clever PCBs Straighten Out The Supercon SAO Badge

January 13, 2025 by No comments

When we decided that Simple Add-Ons (SAOs) would be the focus of Supercon 2024, it was clear the badge would need to feature more than just one or two of the requisite connectors. We finally settled on six ports, but figuring out the geometry of getting all those ports on the badge in such a way that the SAOs wouldn’t hit each other was a bit tricky. In early concept drawings the badge was just a big rectangle with the ports along the top, but it was too ugly.

In the end we went with a somewhat organic design — an electronic “flower” with the radially arranged SAOs forming the petals, but this meant that that none of the SAOs were in the traditional vertical orientation. Luckily, [Adrian Studer] designed a couple of PCBs that not only resolve this issue, but add a seventh SAO port for good measure.

In the project repository you’ll find two PCB designs. The first, “SAO Up” is essentially a little arm that turns the SAO port 90 degrees. This doesn’t exactly get them vertical, in fact, whether or not the new orientation is actually an improvement for the top two SAOs is perhaps debatable. But it definitely helps on the lower SAOs, which are essentially upside down in their original configuration.

The real star of the show is “SAO Bridge”, a wavy board that connects across the two midline SAO ports on the Supercon badge and turns it into a set of three (nearly) horizontal connectors across the front. The center port is particularly helpful in that it gives you a place to put unusually wide SAOs.

As a reminder the Supercon SAO badge, and the winners of the 2024 SAO Contest, will be making the trip across the pond for Hackaday Europe in just a few months. That means you’ve still got plenty of time to have a few of these CERN-OHL-P licensed boards made up.

Raspberry Pi Hack Chat With Eben Upton

January 13, 2025 by 18 Comments

Join us on Wednesday, January 15 at noon Pacific for the Raspberry Pi Hack Chat with Eben Upton!

join-hack-chatThe Hack Chat has been on an extended hiatus, but we’re back for 2025 and coming strong out of the gate! We’ve been trying to get Raspberry Pi co-founder and CEO Eben Upton on the chat for a while, but there was that whole thing of taking the company public that probably distracted him a wee bit. That’s fine though, because we know he loves getting in the trenches with the hacker community and talking about the things we all love to talk about. It’s not often that you get a chance for a one-on-one like this, so make sure you join us with all your Pi-related questions.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, January 15 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

[Image credit: Sniper Zeta, CC BY-SA 4.0]

How Nyan Cat Was Ported To UEFI

January 13, 2025 by 13 Comments

The Unified Extensible Firmware Interface (UEFI) took over from the classical BIOS some years into the new millenium. It’s typically used for running a computer at the basic pre-OS level, and most of us don’t even notice it past boot time. However, you can do some neat things in this space—you can even port over Nyan Cat if you’re talented like [Cornelius].

That’s fun. Set your friend’s computer to boot into this instead of their OS by default and see how long it takes them to figure it out.

Yes, Nyan Cat is now available as a UEFI application, running via the EFI Simple Text Output Protocol. [Cornelius] approached this creation by first learning Rust, before progressing to the Hello World stage. Before long, the computer was booting up to display a simple text message with no OS required.

From there, creating the Nyan Cat animation required figuring out how to display it as a bunch of dancing characters, which is where the Simple Text Output Protocol came in. Nyan Cat was really the perfect animation for the UEFI environment, since its simple pixel art style was easily recreated with text. With a bit of work, the animation came together, with a remarkable resemblance to the original artwork.

All that’s missing is a routine to play the music over a PC speaker; only, those are hardly a thing anymore. A pity! In any case, if you’ve been cooking up your own nifty UEFI hacks, don’t hesitate to drop us a line!

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

Keebin’ With Kristina: The One With The Holey And Wholly Expensive Keyboard

January 13, 2025 by 10 Comments

An Ultimate Hacking Keyboard (UHK) with DIY rainbow keycaps.
Image by [jwr] via reddit
The Ultimate Hacking Keyboard (UHK) line is, as the name suggests, a great choice for a lot of people. They’re each a toe-dip into the ergonomic waters with their split-ability and those beginner thumb clusters.

However, [jwr] was not completely satisfied and decided to make a custom set of keycaps. The idea was to create ‘caps without the “annoyingly abrasive texture of PBT”, that are larger than average for larger-than-average fingers. Finally, [jwr] wanted the Function row to tower over the number row a little, so these have a taller profile.

So, what are they made of? The look kind rubbery, don’t they? They are cast of pigmented polyurethane resin. First, [jwr] designed five molds in Fusion360, one for each row. Then it was time to machine master molds via CNC in foam tooling board. These were filled with silicone along with 3D-printed inserts, which produced silicone molds for casting keycaps four at a time in resin.

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Using Audio Hardware To Drive Neopixels Super Fast

January 13, 2025 by 17 Comments

Here’s the thing about running large strings of Neopixels—also known as WS2812 addressable LEDs. You need to truck out a ton of data, and fast. There are a dozen different libraries out there to drive them already, but [Zorxx] decided to strike out with a new technique—using I2S hardware to get the job done. 

Fast!

Microcontrollers traditionally use I2S interfaces to output digital audio. However, I2s also just happens to be perfect for driving tons of addressable LEDs. At the lowest level, I2S hardware is really just flipping a serial data line really fast with a clock line and a word select line for good measure. If, instead of sound, you pipe a data stream for addressable LEDs to the I2S hardware, it will clock that data out just the same!

[Zorxx] figured that at with an ESP32 trucking out I2S data at a rate of 2.6 megabits per second on the ESP32,  it would be possible to update a string of 256 pixels in just 7.3 milliseconds. In other words, you could have a 16 by 16 grid updating at over 130 frames per second. Step up to 512 LEDs, and you can still run at almost 70 fps.

There’s some tricks to pulling this off, but it’s nothing you can’t figure out just by looking at the spec sheets for the WS2812B and the ESP32. Or, indeed, [Zorxx’s] helpful Github page. We’ve featured some other unorthodox methods of driving these LEDs before, too! Meanwhile, if you’ve got your own ideas on how to datablast at ever greater speeds, don’t hesitate to let us know!

Modern AI On Vintage Hardware: LLama 2 Runs On Windows 98

January 13, 2025 by 27 Comments

[EXO Labs] demonstrated something pretty striking: a modified version of Llama 2 (a large language model) that runs on Windows 98. Why? Because when it comes to personal computing, if something can run on Windows 98, it can run on anything. More to the point: if something can run on Windows 98 then it’s something no tech company can control how you use, no matter how large or influential they may be. More on that in a minute.

Ever wanted to run a local LLM on 25 year old hardware? No? Well now you can, and at a respectable speed, too!

What’s it like to run an LLM on Windows 98? Aside from the struggles of things like finding compatible peripherals (back to PS/2 hardware!) and transferring the required files (FTP over Ethernet to the rescue) or even compilation (some porting required), it works maybe better than one might expect.

A Windows 98 machine with Pentium II processor and 128 MB of RAM generates a speedy 39.31 tokens per second with a 260K parameter Llama 2 model. A much larger 15M model generates 1.03 tokens per second. Slow, but it works. Going even larger will also work, just ever slower. There’s a video on X that shows it all in action.

It’s true that modern LLMs have billions of parameters so these models are tiny in comparison. But that doesn’t mean they can’t be useful. Models can be shockingly small and still be perfectly coherent and deliver surprisingly strong performance if their training and “job” is narrow enough, and the tools to do that for oneself are all on GitHub.

This is a good time to mention that this particular project (and its ongoing efforts) are part of a set of twelve projects by EXO Labs focusing on ensuring things like AI models can be run anywhere, by anyone, independent of tech giants aiming to hold all the strings.

And hey, if local AI and the command line is something that’s up your alley, did you know they already exist as single-file, multi-platform, command-line executables?