Win95-Tracker-CYD Is A Cheap Yellow Mod Tracker With I2S

May 8, 2026 by Tyler August 7 Comments

The Cheap Yellow Display is a great little module to start a project with, but it wouldn’t necessarily be our first choice for an audio device. That’s because the PWM on the ESP32 isn’t exactly going to put out hi-fi, and the I2C pins needed for the I2S audio protocol aren’t broken out on the CYD board. That didn’t stop [ivans805] AKA [Ill-Town-5623]– he wanted a mod tracker, he had a CYD board, and necessity is the mother of invention.

It isn’t exactly a ground-breaking hack: he’s just tossed a bodge wire to the pin he needs on the ESP32, and run it to the I2S sound module. Still, in this era of endless modules it’s nice to see someone hacking what they have rather than running to AliExpress or somewhere else for a part that has everything the project needs built in.

The bodge wire is how you know it’s a hack.

What really caught our eye when we saw this project on the ESP32 subreddit was the aesthetics. It might be called “Win95-Tracker-CYD” but that interface just screams “Amiga” to us– look at that Boing Ball! Given where MOD files come from, that’s perfect. The UI was made with Lopaka.app, which we haven’t seen before but appears to be a sort of WYSIWYG editor for embedded device interfaces.

While you don’t need an ESP32 to play mod files– the diminutive CH32 can manage the task— there’s no arguing the CYD could make a nice little player. If you actually wanted to push its limits, you might try a 3D engine instead,

3D Printed Train Whistles Sound Out At Full Scale

May 7, 2026 by Tyler August 10 Comments

The age of steam is long gone, but there are few railfans who don’t have a soft spot for the old rolling kettles. So you’d best believe when [AeroKoi] talks about 3D printed train whistles, that’s steam whistles. Generally speaking, Diesels have horns.

You would not expect printed plastic to hold up to live steam– but that’s why [AeroKoi] uses compressed air. Besides, it’s a lot easier to both justify and maintain an air compressor than a boiler in the shop. At least some hobbyists say it doesn’t make a huge difference with brass whistles, so it should be good enough for plastic. What’s interesting is that even with 120 PSI blasting through them, these multi-part prints held together and sounded amazing.

[AeroKoi] does demonstrate there was a learning curve to climb before he had a good whistle design, and shows you what features worked best. He shared two successes on Thingiverse: A 6-Chime whistle from the Sante Fe Railroad, and a Northern Pacific 5-chime whistle, both 4″ in diameter and printed in vertically sectioned parts. The Northern Pacific is not to be confused with the totally different Union Pacific Railroad, whose famous “Big Boy” also had a whistle feature in the video — though evidently he’s not as happy with it, since he did not share the design.

Those are all North American designs, but there’s no reason this technique wouldn’t work to replicate a more European sound; one of his early experiments was kind of going in that direction already. Of course if you want a perfect replica, the old ways are the best ways: cast brass and live steam. We’ve had a few articles about train whistles in the past, one of which was a doorbell.

Continue reading “3D Printed Train Whistles Sound Out At Full Scale” →

RGB image from the projector, with human for scale.

RGB Laser Projector Does Colorful Asteroids And Much More

May 6, 2026 by Tyler August 13 Comments

Have you thought about building a galvonometer-based laser projector, but don’t know where to start? There are a lot of resources out there, but you could do worse than to check out [Breq] and [Mia]’s laser vector project, which provides a very well-documented and low-cost starting point. They boast that the most expensive part of the project was the ANSI-certified safety glasses, which shows a dedication to safety we wish more people would show when playing with coherent light.

The rest of the parts — from the galvos to the RGB lasers module with dichoric mirrors to keep everything on the same beamline, to the ESP32 module driving everything — was ordered from AliExpress, and not from the most expensive vendors, either. Considering that, it works remarkably well.

If you’re not playing *Asteroids* on your vector display, why even bother?

Like all DIY laser projectors, this one does vector graphics, sweeping the beam fast enough that the human eye registers crisp, clean lines. Galvonometers, or galvos for short, take analog input, so a DAC is needed — fortunately the ESP32-S2 comes with a pair built in. The custom PCB of course has audio-in for the usual Lissajous lightshow or oscilloscope music, but with an ESP32 as the brains, you can do a lot just inside the projector.

Like what? Well, play Asteroids, for instance, using Wiimote controllers. Project a lovely clock. Render text input in various single-stroke fonts. More to the point, since this is a projector, take arbitrary SVG data and project literally any image you’d like — as long as it doesn’t have too many lines, at least. The galvos in this project are rated at 20,000 points per second, which is not exceedingly fast: they were chosen to meet the budget, not the greatest-possible speed.

More to the point is that this is one of the better-documented projects of this type we’ve seen. [Breq] doesn’t just tell us how to build the projector, but why they designed it that way. We really encourage you to give it a read if you’ve been thinking of getting into this sort of display.

We’ve seen plenty of laser projectors before, most of them producing vector images like this one. If you really must have a raster display, though, that’s also an option. Don’t count out vector images, though — they could even replace your Christmas lights.

Thanks to [CapinRedBeard] for the tip! Remember to send any bright ideas you see to our tips line, coherently lit or no.

3D reconstruction of x-rayed worms. X-ray absorbing particles in the guts are shown in white.

Earthworms Don’t Bio-Accumulate Microplastics, So There May Be Hope For Us

May 5, 2026 by Tyler August 26 Comments

Microplastics absolutely saturate the Earth’s environment, and that’s probably not a good thing unless you’re looking for a sediment marker for the Anthropocene period. On the other hand, environmental contamination only becomes a really big problem if it bioaccumulates– that is, builds up in the tissues of plants and animals. At least when it comes to worms, that’s not the case with microplastics, according to new research from the Canadian Light Source at the University of Saskatchewan.

Pictured: Not an Igloo.
Credit: David Stobbe / Stobbe Photography, via University of Saskatchewan

The Canadian Light Source isn’t just some hoseheads in an igloo with a flashlight– it’s a 2.9 GeV Synchrotron tuned to produce high-energy photons. Back when Synchrotrons were used for particle physics, Synchrotron radiation was a very annoying energy sink, but nobody cares about 2.9 GeV electrons anymore. So rather than slam them into each other or a static target, the electrons just whip about endlessly, giving off both soft- and hard X-rays for material science studies– or, in this case, to observe the passage of polyethelyne microplastic particles through the guts of some very confused earth worms. To make them detectable by x-ray, the polyethylene was bonded to barium sulfate, an x-ray absorber. Equally opaque barium titanite glass microspheres were used with different worms, as a control.

Despite being fed soil enriched with far more plastic than you’ll find outside of a 3D print farm, it seems the worm’s digestive system was able to reject the particles, even those as fine as 5 microns. That’s a good thing, because if the worms were absorbing plastic from the soil, it’s likely their predators would absorb it from the flesh of the worms, so and so forth up the food chain in the sort of cascade that made DDT a problem and makes mercury compounds so serious. If the worms are rejecting these compounds, there’s a chance other creatures can too– and at the very least, it means they aren’t building up on this bottom rung of the foot chain. If you’re looking for a more technical read, the full paper is available here.

It’s too early to say what this means for how microplastics get into humans and other animals, but it’s hopeful. Equally hopeful was the recent finding that studies that don’t rely on football-field sized X-ray machines might be picking up on microplastics from lab gloves, skewing results.

Header image: the digestive systems of earth worms as imaged by the Canadian Light Source. Credit Letwin, et al,
Environmental Toxicology and Chemistry, vgag072, https://doi.org/10.1093/etojnl/vgag072

LightInk, A Solar Powered ESP32 Smartwatch

May 5, 2026 by Tyler August 11 Comments

There’s something about the ESP32 family of microcontrollers and timekeeping. We probably see it in clocks as often as we do anything else; we also probably see more clocks with one as the beating heart than any of the many other possible timekeeping options.

[Daniel Ansorregui]’s LightInk watch is no different in that regard — but it is very different in one important detail, because unlike most other smartwatch designs, you won’t have to worry about battery life. Outside of gloomiest Gotham, its built-in solar panel should be able to keep it charged.

That’s for a few reasons. The obvious one is the e-ink display, which only takes a sip of power during updates. That’s hardly unique to [Daniel]’s projec t– he quite explicitly calls out the Watchy project, which we featured previously, as where he got the idea of putting e-ink and an ESP32-PICO together on his wrist. What is unique is the delightful hack [Daniel] is using to minimize power usage, which is our favorite part.

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Sunlight Powered, Sunlight Readable: Solar Case For Nook Simple Touch

May 4, 2026 by Tyler August 6 Comments

When life gives you lemons, you make lemonade. What if life gives you a pile of old e-book readers? Well, when [spiritplumber] got box of old Nook Simple Touch devices, he decided to design solar-powered cases to help boost the old batteries. It makes perfect sense to us: sunlight readable screen, sunlight chargeable battery.

It looks like he’s got a pair of panels built into the 3D printed case. He recommends using any TP4056-based charger, and tying into the battery test points, not the 5 V supply. It won’t hurt anything if you do, apparently, but the device will think it’s plugged in an refuse to turn off the WiFi. That’s no big deal when you’ve got a continental power grid on the other end of the cable, but charging from a small panel on the back of the case doesn’t always give you enough juice to waste on unneeded radio activity. Especially indoors — these panels are apparently big enough to trickle-charge the device under artificial light, which is a nice, if doubtless slow feature.

The design is open source, and includes SketchUp design files as well as the exported .STL, so if you’ve got a hankering to edit this to fit a different e-book reader, you can. He also provides a handy-dandy guide to root this model of Nook, and if you’re on Hackaday we probably don’t need to explain why you might want to.

We’ve seen the Nook Simple Touch go some interesting places — like into the clouds as a glider computer — but solar power is a new hack for this device, at least on this site. We don’t know if [spiritplumber] has a green thumb, but he’s evidently got some environmental bones in his body: his last featured project was about improving quadcopter efficiency with a wing and a prayer.

ESP32 Hosts SolarPunk Message Board

May 4, 2026 by Tyler August 8 Comments

Solarpunk is sometimes thought of as the “good ending” to cyberpunk– there’s technology, but it’s community-focused instead of in the hands of evil conglomerates, and– if the name doesn’t give it away– renewably powered. [Victor Frost] found that image of the future inspiring enough to create this ESP32-hosted community hub. Yes, it looks like a lantern, but it’s actually a very-local webserver.

It looks like a lantern, but it’s got a server inside. Plus two 18650 cells to charge from a solar panel that’s presumably off-camera.

Local webserver sounds like an oxymoron, but this device does serve a page over HTTP… just, not on the world-wide web. Instead the only way to access it is via its own Wireless Network– he’s using the ‘captive portal’ that forces you to log into public wifi to direct people to a community message board.

It’s unmoderated, and unfiltered– users can post what they like, but given that they have to be within a few meters of the device, it’s not exactly anonymous. It’s a lot like the community center corkboard brought into the 21st centruy, which is very in keeping with the solarpunk ethos.

For ease of updates, he’s subdivided the ESP32’s flash into three partitions: one for the data, and two for the software, using LittleFS. This allows live updates and keeping a known-good backup for the quickest possible turnaround and/or rollback. One interesting thing is that his who UI– the actual web site, HTML, CSS, and JS– is all crammed into a single string in PROGMEM rather than files on the little file system. It’s an interesting choice, and makes for quick updates, firmware and UI in one go. Not everyone will like it, but it works for [Victor]. The code is, of course, on GitHub under the GPL— there’s a lot of overlap between the open source and solarpunk ethos, after all.

It’s a bit of a pity that he missed our Green Powered Challenge, as this project would have fit right in to the PV category, considering it runs on a 6W panel. For all the cyberpunk and solar power you see on this website, you’d think the “solarpunk” tag would be more popular, but no– all we have is this stained-glass robot.

Thanks to [Victor] for the tip! If you missed our contest, too, no worries– we take projects of all colours, green or otherwise, all the time. Just drop us a tip.