Mysterious Files PH

The Playdate is a small handheld console with a dedicated fanbase. Among them is [Cristina Ramos], who recently decided to try and push the limits of the hardware by implementing a 3D renderer for the platform.

[Cristina] began by implementing a raycaster. This is a very simple way to do 3D on limited hardware, and this technique was used by some early games like Wolfenstein 3D. However, for [Cristina], it was more a test to get an idea of the performance limitations of the Playdate. After getting her feet wet with that, she stepped up to implementing a renderer that relied on binary space partitioning, which could load map files in the same format used by the classic Quake engine. There was naturally plenty of work to do to handle things like texture mapping and lighting, too, particularly given the vagaries of working with the Playdate’s 1-bit monochrome screen. Using a simplistic, cel-shaded like approach for textures gave things a good look while preserving visual readability on the low-resolution screen.

The 3D engine and associated game remain a work in progress for [Cristina] — we look forward to seeing where the project goes next. We’ve seen similar projects on resource-limited platforms before, too.

I was told you couldn't do 3D on the Playdate, so I did it.Then I was told there was no way I could create exterior levels like those in Mirror's Edge, so I proved them wrong again.

— Cristina Ramos (@saffroncr.bsky.social) 2026-07-22T08:57:09.594Z

Community-led open source project hosting site Codeberg has formally announced that projects whose code is largely or fully machine-generated through LLMs and other ‘AI’ tools will no longer be welcome. This follows on the heels of a similar ban on cryptocurrency-related projects.

The community vote was on two issues, the first being the notion that scraping of project code for the use in LLMs should be forbidden, which was a motion that easily passed. The second motion was on disallowing projects whose code was substantially generated by LLMs like Claude, OpenAI Codex, and similar. This motion passed with 358 in favor versus 144 against.

In the earlier linked blog post the reasoning behind especially this second issue is expanded upon, covering not only ‘license whitewashing’, but also the direct and indirect hardware costs, with the expanding ‘AI’ datacenter hyperscaling having massively increased hardware costs for Codeberg over the past years, as the costs have been largely externalized.

Also covered is also the aspect of these LLM-based tools destroying the OSS community, which is something that is backed up by recent studies. Even if we ignore that such LLM-tools are destroying the cognitive abilities of its users, there’s an argument to be made that if LLM-scraping is disallowed, then it’s consistent to also not allow LLM-generated code.

In the Terms of Use you can see these changes, both for LLMs and for cryptocurrency projects.

Thanks to [mk-fg] for the tip.

[Myth Made] has a goal to get into writing. However, she likes to do things the aesthetic way, rather than the easy way. Thus, she has eschewed simple word processing on a conventional computer, instead choosing to build a remarkably attractive writing deck styled after a classic typewriter.

The build began with a mechanical keyboard with a compact layout. The square keycaps were swapped out for custom 3D printed versions that were rounded to suit the desired look. [Myth Made] used a neat technique where the caps were colored in with a paint marker and then ran through a laser engraver to bond the paint to the surface to make all the key markings.

With the input side sorted, the rest of the build could progress. The typewriter shell was printed in multiple parts, and then welded together with acetone. This was then covered with an ABS-acetone solution that helped remove some of the surface artifacts, before priming and paint. As for the electronics side, a Raspberry Pi Zero runs the show, hooked up to a Waveshare e-ink display which can be cranked up and down like a piece of paper coming out of a typewriter. There’s also a lovely 7-segment display which displays the current word count.

It’s a fun build that looks utterly joyous to use. Sometimes leaning into the aesthetic side of a project is what makes it so magical.

On this episode, Hackaday editors Elliot Williams and Tom Nardi discuss their love of electronic paper, clunky cartridges, and keeping old games alive by any means possible. You’ll also hear about getting the most out of the sensors in our 3D printers, playing with X-rays at home, a ring that runs Java, and a roulette wheel that outgrew its 555 timer. Stick around to the end to learn about a different sort of IRC that’s even more niche than the one you’re probably familiar with, as well as the logistical challenges and potential benefits of catching rockets with a giant net.

Check out the links if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download in DRM-free MP3.

Episode 379 Show Notes:

News:

• 2026 Hackaday Supercon: Call For Proposals
• Remembering The Zilog Z80 As It Turns Fifty Years Old

What’s That Sound:

• We’re putting What’s That Sound on hold while we sort out new prizes. Stay tuned.

Interesting Hacks of the Week:

• 20 FPS On E-Paper Display Without Help
  • E-ink Display Driven DIY
  • Clever E-Ink Driver Does 32 Levels Of Grey, Avoids Update Flicker, And More
  • Behold A 60 Hz Refresh Rate E-ink Monitor
• Old SSDs Find New Life As Game Cartridges
• 60 FPS NES Emulator On ESP32
• Automated Pressure Advance Using A Bed-Leveling Sensor
  • Direct Pressure Advance Measurement For Fast Calibration
• Old TV Vacuum Tube Turned DIY X-Ray Machine
  • X-rays with a DY86 – BOGIN, JR.
• Dress Up Your YubiKey With This Web-Based Tool

Quick Hacks:

• Elliot’s Picks:
  • Echolocation For Drones
  • Java Ring Restored After Nearly 30 Years
  • Tired Of Xargs?
• Tom’s Picks:
  • Seven Ways To Install Magnets Into Your 3D Prints
  • ESP32-driven Roulette Wheel Could Have Used A 555, But That Didn’t Have WiFi
  • Flex Filament Stuck To Your Build Platform? Reach For The Isopropanol

Can’t-Miss Articles:

• Postal IRCs Are Almost A Thing Of The Past
• Launching Rockets Is Hard, Bring Them Back Is Harder

Despite their small size, mosquitoes are one of the deadliest creatures on Earth, and keeping them away from you is one of the best ways to stay safe. DEET has been the mainstay of insect repellents for decades, but what if there was a repellent you could grow yourself?

Researchers at Cardiff University found that the essential oil from catnip plants (Nepeta cataria) could be as effective as DEET at repelling mosquitoes when applied as a 6% lotion. The oil has been shown to be effective against many species of mosquitoes, ticks, and mites in previous research. You can look at the paper for details, but the catnip oil was obtained through steam distillation followed by some processing with hexane. The essential oil was then mixed with “water, glycerin, emulsifying wax, cetyl alcohol, cetyl stearyl alcohol, shea butter, glycerol monostearate, olive oil, coconut oil, sunflower oil, methyl paraben, propyl paraben and silicone oil.” We suspect that list will look familiar to anyone who’s read an ingredient label of most any store bought lotion, unless it was paraben free.

The Guardian’s coverage quotes one of the researchers, [Dr. Simon Scofield]: “We did not conduct any experiments to see if it is attractive to cats, but given that the active ingredient [nepetalactone] has well-known cat-attractive properties, I would expect they would quite like it,” he said. Depending on how your cats react, you may want to consider applying the lotion shortly before departing home.

If you want some more options in your mosquito defense, how about becoming a bug zapper, using drones and sonar, or genetically modifying mosquitoes to curb their numbers.

Trains are a great way to get around. You just have to make sure you’re across the schedule if you intend to get where you’re going in a timely manner. Train departure boards exist for that very purpose. As a train fan, [Jon] always wanted such a thing, so decided to build one for himself. 

The build started, as so many do, with a Raspberry Pi 4, with [Jon] deciding on the 1GB model. Hooked up to either an Adafruit RGB Matrix Bonnet, or an Electrodragon 3-port RGB Matrix board, it’s then possible to get the Pi running three to four HUB75E LED matrixes. Each matrix consists of 128 x 64 pixels, so stacking up a bunch of them can make a nicely-sized departure board that’s easily readable. [Jon] was sure to hook up a nice, juicy 5-amp 5-volt power supply to ensure there wouldn’t be any surprise brownouts under normal usage conditions. From there, it’s simply a matter of having the Pi query the Rail Data Marketplace in order to get the relevant schedule data to display on the board.

If you want to get information on your local rail services at a glance, or just want to impress your fellow foamers at your next railfan gathering, a build like this is a great way to go. We’ve seen similar builds before, too. Video after the break.

Today’s phone microphones are perfectly adept at picking up sound in all sorts of conditions, and they’re backed by all kinds of processing techniques to filter out noise and capture clean audio. [mcore1976] has been working on a device to jam phone microphones that might be listening in, however, countering fancy processing techniques in turn. 

The build uses a microcontroller brain to control an array of ultrasonic transducers. [mcore1976] has created many revisions of the project, each time improving its ability to jam microphones in modern hardware. The latest revision uses an RP2040 microcontroller and a MOSFET drive stage to control 20-80 ultrasonic transducers. They’re driven with a PWM signal generated from the RP2040 itself. The signal output is specifically modulated to try and confuse the automatic gain control systems used in many modern phones in order to make it difficult for them to record clear audio when the jammer is running. As [mcore1976] demonstrates with an iPhone 17, his voice is completely lost amidst unintelligible garbled noise while the jammer is switched on.

It’s a niche idea, and perhaps most interesting because it affects phone microphones while being largely inaudible to the human ear. We’ve featured other interesting jamming devices of late, too. Video after the break.