An Improbable, Doomed Star System In A Clockwork Coffee Table

The major objects in our solar system orbit along the plane of the ecliptic, plus or minus few degrees, and it turns out most exoplanet systems are the same — pretty flat, with maybe one highly-inclined outlier. But at [The 5439 Workshop], they don’t care about these details: [5439] has come up with a mechanism to drive inclined orbits in an orrery, and he’s going to use it. The star is exploding, too, because why wouldn’t it be?

While the cinematography of this build video might not be to everyone’s taste, it’s worth watching to see the details of the project. The sliding mechanism to “explode” the star by sliding plates across each other is quite well-done, although perhaps not much not designed for assembly (we’re quite impressed he got it together). It isn’t quite the iris we had expected, as there’s a double-ratchet inside to drive the slow collapse/fast expansion dynamic [5439] is going for. It looks more like the breathing mode of a cepheid variable star than an explosion to us, but it’s still a fascinating piece of laser-sintered aluminum.

The driving mechanism for the inclined orbits is fairly simple, but also worth examining, as we’re not aware of anyone having used it before. The gear rings holding the planets are tilted, and are driven by straight vertical shafts via gears that pivot on knuckle joints. It’s not a revolutionary design, but it’s a big part of what makes this build unique. Since the solar system is very flat, clockwork orreries tend not to bother showing orbital inclination at all. Given the way planets are believed to form from a protoplanetary disk, a system with this many planets in such differing orbital planes seems unlikely to occur naturally, but it certainly adds visual interest.

We like model solar systems around here, be they made from brass and steel, molded plastic LEGO bits, or 3D printed and CNC routed aluminum like this one. That you can sit a coffee mug on it is just bonus. Continue reading “An Improbable, Doomed Star System In A Clockwork Coffee Table”

Tiny386 On An Espressif ESP32-S3

Some people may remember the joys of trying to boot Linux on an 8-bit AVR microcontroller, which was an absolute exercise in patience. In comparison [He Chunhui]’s Tiny386 emulator running on an ESP32-S3 MCU is positively zippy when it boots and runs Windows 95. The provided video (also embedded below) makes clear that while you can comfortably waddle off to prepare and pour a fresh cup of tea, it’s actually borderline usable.

The source code can be obtained via GitHub, which contains not just the basic emulated 80386 CPU written in C99, but also peripherals borrowed from TinyEMU and QEMU, along with a SeaBIOS ROM. In addition to the Windows 95 demo it’s claimed that Tiny386 should be able to run most 16/32-bit software.

Right now the ESP32-S3 version targets the JC3248W535 board, which is a roughly $30 development board featuring a built-in display with touch screen and an ESP32-S3 module. Although it has a USB-C port, it appears that this one is just for programming and not for the USB peripheral of the ESP32-S3. With the USB OTG peripheral used, one could conceivably make a small 386 system based around an ESP32-S3 that features a USB hub to plug a keyboard, mouse, etc. into.

Considering that the Tiny386 emulator is a very simple and straightforward approach to emulating an early-90s PC, some optimization might enable a pretty zippy general purpose PC for early 90s software. Quite a boost from watching Linux struggle into a command line on an AVR, indeed.

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What Do You Call An Ekranoplan With An Outboard Motor?

If there’s one thing [rctestflight] likes, it’s… probably radio controlled test flights. If there are two things [rctestflights] likes, the second one is probably ground-effect vehicles, AKA Ekranoplans. Tired of having them flip over and crash, he’s trying an an innovative solution: stick a planing hull on it.

Ekranoplans have a stability problem because the center-of-pressure isn’t static: as the wing gets closer to the ground, the high pressure cushion of air that creates the ground effect tends to put more lift rearwards. The net effect of that is to torque the vehicle nose-down, which is kind of a self-limiting problem at a fraction of a wingspan’s altitude. The opposite problem is more concerning: the higher the ekranoplan gets, the more it wants to nose up, and there’s nothing to stop it. That leads to the vehicle flipping over. Continue reading “What Do You Call An Ekranoplan With An Outboard Motor?”

3D Printing A Piano Action

Part of the reason there are always free pianos on your digital classifieds listing of choice is that, at least economically speaking, a piano is less of a musical instrument and more of a complicated machine that can and will wear out (not to mention the physical difficulty of actually moving one). Once a piano reaches that point, whether through age, use, or neglect, at that point it’s to intents and purposes worthless. But still, they’re essentially just machines. [Toast] figured that, since 3D printers not only can print all kinds of other machines and musical instruments alike, he would take a stab at combining these two and made his own 3D printed piano.

A piano’s action is the mechanical linkage between the keys and the strings of the piano themselves. Over many hundreds of years this has developed into a complicated series of levers which not only rapidly strike strings when a key is pressed, but also mute the strings while the key is not being pressed and strike the strings in a way that the hammer won’t be pressed into the strings if the player leaves their finger on a key. Rather than try to recreate all of this in meticulous detail, [Toast] has swapped out the strings for a series of tubes which, unlike strings, do not much change their musical behavior if the hammer remains on the tube after being struck. This greatly simplifies the action (and cost) of his miniature piano.

The piano works by positioning hammers above these tubes, which strike downwards when a musician depresses the keys. Rubber bands return the hammers to their upright positions after the key is lifted. The instrument went through a few stages of design as well where [Toast] refined the size and shape of the tubes as well as improved the way by which the hammers are attached to the keys.

Is it still a piano if it has pipes instead of strings? Perhaps, but at the very least we can all agree that he’s built a working keyboard action capable of producing music, if not an outright definitionally-accurate piano. It’s an interesting build that we hope to see more iterations of in the future, if not to build a more functionally accurate 3D printed piano action then to see what is possible from a 3D printer in the piano space. Despite their complexity and weight, pianos are a fundamental and popular instrument in the Western music tradition and we’ve seen many interesting builds around them like this modern player piano built with a series of solenoids. Continue reading “3D Printing A Piano Action”

2025 Component Abuse Challenge: Relay Used As Guitar Pickup

We’ve all built projects that are a rats’ nest of wiring and feature creep, but the best projects in the end are usually those that use a simple solution to elegantly solve a problem. [Kauz] had been thinking about a unique type of electric guitar pickup for a while and rather than purchase an expensive option or build a complex microcontroller-based system he found his elegant solution in the form of a common electronic component.

The core of this idea is that guitar pickups are essentially coils of wire, and are surprisingly similar to the coils of wire found in electromechanical relays. [Kauz] has used six small relays, left them unmodified, and then built an amplifier circuit for each to allow the vibrations of the guitar strings to resonate in the relay coils, eventually producing a sound. Not only do the relays work perfectly well as pickups, but [Kauz] also created a mixing board that allows the six relays to be combined into two channels, allowing for options like stereo sound for different strings directly out of the guitar or for different effects to be applied to different strings.

The build also allows for some interesting options in future versions as well. [Kauz]’s plans are eventually to build this into an instrument which can output polyphonic MIDI signals, where various strings can behave as different instruments. In theory, with six circuits six different instruments can be produced, and we’re excited to see what the next versions will look and sound like. In the meantime, be sure to check out some other guitar pickups we’ve seen that use even simpler parts found lying around the workbench.

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The Pi 500 Turned Overkill Bluetooth Keyboard

Perhaps we’ve all found ourselves at one time or another with more computers in use than keyboards and other peripherals at hand to use them with. With a single user you can make do with remote terminals or by simply plugging and unplugging, but with multiple users it’s not so easy.

CNX Software’s [Jean-Luc Aufranc] had just such a problem involving broken keyboards and a forgotten wireless dongle, but fortunately he had just reviewed the latest version of the Raspberry Pi 500 all-in-one computer with the fancy mechanical switches. His keyboard solution is inspired but completely overkill: to use the full power of the compact Linux machine to emulate a Bluetooth keyboard.

At the heart of this hack is btferret, a Bluetooth library. Run the appropriate software on your Pi, and straight away you’ll have a Bluetooth keyboard. It seems there’s a bit of keymap tomfoolery to be had, and hitting the escape key terminates the program — we would be caught by that SO many times! — but it’s one of those simple hacks it pays to know about in case like him you need to get out of a hole and happen to have one of the range of Pi all-in-one machines to hand.

If IRobot Falls, Hackers Are Ready To Wrangle Roombas

Things are not looking good for iRobot. Although their robotic Roomba vacuums are basically a household name, the company has been faltering financially for some time now. In 2024 there was hope of a buyout by Amazon, who were presumably keen to pull the bots into their Alexa ecosystem, but that has since fallen through. Now, by the company’s own estimates, bankruptcy is a very real possibility by the end of the year.

Hackaday isn’t a financial blog, so we won’t get into how and why iRobot has ended up here,  although we can guess that intense competition in the market probably had something to do with it. We’re far more interested in what happens when those millions of domesticated robots start getting an error message when they try to call home to the mothership.

We’ve seen this scenario play out many times before — a startup goes belly up, and all the sudden you can’t upload new songs to some weirdo kid’s media player, or the gadget in your fridge stops telling you how old your eggs are. (No, seriously.) But the scale here is unprecedented. If iRobot collapses, we may be looking at one of the largest and most impactful smart-gadget screw overs of all time.

Luckily, we aren’t quite there yet. There’s still time to weigh options, and critically, perform the kind of research and reverse engineering necessary to make sure the community can keep the world’s Roombas chugging along even if the worst happens.

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