2026-04-28 19:00:41
There’s a rule of thumb when it comes to FDM printing that overhangs are really only possible to an angle of around 45 degrees or so. If you try to squirt out plastic with nothing supporting it, it just goes everywhere. However, a new slicer hopes to enable printing up to 90-degree overhangs with some creative techniques.
The software that enables this is called WaveOverhangs, and currently exists as a fork of OrcaSlicer. The idea is straightforward enough — using unique toolpathing to create rings of deposited material that fasten to those laid down before them in the same layer. Thus as the printer lays down a layer into bare space, the deposited plastic is, ideally, able to fix on to the supported edge. As the next ring is laid down, it grabs on to the cooled ring laid down before it, and so on. The idea is inspired by wave propagation, hence the name. You can see a demonstration of the software in the video below by [Cocoanix 3D Printing].
It’s still a very new technique. The slicer has a whole bunch of knobs to turn and two different algorithms. Get the settings just right and you can print horizontal overhangs successfully. There aren’t exactly presets yet, this is something to explore with trial and error. If you test it out, don’t forget to upload your results to the Community Gallery so the developers can see what works and what doesn’t.
We’ve explored how smart slicers can do amazing things before, too, particularly when it comes to things like bridging.
2026-04-28 16:00:05
If you mention the word bus, you might think of public transportation or, more likely for us, a way to connect things together. But in the satellite world, the bus is the part of a vehicle that supports the payload but isn’t itself the payload. Typically, that means the electric power system, propulsion, radios, and thermal control, among other systems. If you are designing a CubeSat, you will want to read A Guide to CubeSat Mission and Bus Design by [Frances Zhu].
The Creative Commons-licensed book has twelve chapters, ranging from systems engineering — that is, defining what you want to do — to analyzing structures, handling power, setting up communications, and more. Of particular interest to us was the chapter on command and data handling. The final chapters cover software, system integration, and there’s even a chapter on Ethics.
If you want to build a CubeSat or just want to learn more about how satellites actually work, this is a great read. There are videos and other features, too. If you don’t like reading in your browser, you can download an EPUB, PDF, or MOBI near the top of the page.
There are many resources for the want-to-be CubeSat builder. You can even start with an open source design.
2026-04-28 13:00:04
USB wasn’t even a gleam in an engineer’s eye when the Sega Master System hit the market in 1985. Today, we’re up to USB 4 or something, and the USB C connector is becoming a defacto standard for just about everything except desktop computers. [Retrostalgia] is embracing this by mating the control pad from Sega’s first international console with the connector of today.
Naturally, the Sega Master System did not use the Universal Serial Bus to talk to its controllers, so some conversion was in order. That’s achieved with the use of a RP2040 microcontroller, which reads the D-pad and action buttons via its GPIO pins. It then acts as a HID device when plugged into a computer or other USB host, showing up as a simple game controller. This is a particularly easy hack as the Master System controller is so simple, there’s no need to decipher any protocols or anything like that. It’s just about wiring up a few simple buttons. Beyond that, it’s just a matter of hot-gluing the RP2040 into the Master System controller housing, and making some room for the USB C port to sneak out the top. We’d have loved to seen a little extra hackery on this one, perhaps adding some rumble to a controller that was never, ever supposed to have it.
If you want to adapt authentic old controllers to work with modern computers and emulators, this project is a great place to start. It doesn’t get much simpler than the Master System, after all. You can always work your way up to more advanced feats later, like working with the beloved Wavebird. Video after the break.
2026-04-28 10:00:35
Solid state batteries, we are told, are the new hot battery technology that will replace lithium-ion batteries. Soon. Not that we haven’t heard that before. One reason it isn’t dominating the market today is that it’s prone to short circuits during charging. [Dr. Yuwei Zhang and others have published a paper detailing why the shorts happen, which could lead to strategies to improve the technology.
Solid state batteries employ a solid electrolyte and a lithium anode. It is known that, sometimes, lithium metal from the anode forms dendrites that penetrate the ceramic electrolyte and cause it to crack. This is somewhat of a mystery as the lithium is a soft metal (to quote [Zhang], “like a gummy bear.”).
There were two leading hypotheses for the observations. [Zhang’s] team showed that hydrostatic stress made the lithium dendrites act like a water jet, enabling them to penetrate the hard ceramic.
There is still work to figure out what to do about it, but understanding the root cause is certainly a step in the right direction. We’ve looked at these batteries before. We’ve also seen how changing the anode construction might help with the problem.
2026-04-28 07:00:08
Ultrasonic levitation is by now a familiar trick: one or more ultrasonic transducers create a standing wave, and small objects can be held in the nodes of this standing wave. With a sufficiently large array of transducers, it’s even possible to control the movement of the object. This isn’t the only form of ultrasonic levitation, however, as [Steve Mould] demonstrated with his ultrasonic air hockey table.
This less familiar form of levitation was discovered by [Bob Collins] while working on torpedo guidance systems: when he tried to place a glass lens on an ultrasonic transducer it immediately slid off. He found during further experimentation that an ultrasonic transducer would levitate over any sufficiently flat and smooth surface. It works by trapping a very thin layer of air between the transducer and the smooth surface. When the transducer moves sharply toward the surface, it compresses a layer of air in between, and forces some air out, and the reverse happens while pulling back. However, during the downstroke, the gap through which air can escape is narrower than during the upstroke, and there is more surface-induced drag, meaning that the inflow and outflow of air through a narrow gap isn’t completely equal. At a certain distance, inflow and outflow balance, and the transducer floats on a thin layer of air.
In [Steve]’s air hockey arena, the floor oscillates and the pucks levitate over this. Driving it using just one transducer didn’t work, since the floor formed standing waves, and the pucks would get stuck on node lines. Instead, he used two transducers, one at each end of the arena, and drove them out of phase with each other. This created a standing wave and minimized dead spots.
The arena was a bit small (having to be played using toothpicks), but it seemed to work well. If you prefer your air hockey a bit more human-scaled, we’ve seen a table build before. We’ve also seen ultrasonic levitation before, ranging from simple electronics kits to the driving force behind a full volumetric display or photography station.
2026-04-28 04:00:44
Springs are great, but making them out of plastic tends to come with some downsides, for fairly obvious reasons. Creating a compliant mechanism that can be 3D printed and yet which doesn’t permanently deform or wear out after a few uses is therefore a bit of a struggle. The compliant toggle mechanism that [neotoy] designed is said to have addressed those issues, with the model available on Printables for anyone to give a shake.
The model in question is a toggle, which is the commonly seen plastic or metal device that clamps down on e.g. rope or cord and requires you to push on it to have it release said clamping force. Normally these use a metal spring inside, but this version is fully 3D printable and thus forms a practical way to test this particular compliant mechanism with a variety of materials.
The internal spring is a printed spiral spring, with the example in the video printed in PETG. You can of course also print it in other materials for different durability and springiness properties. As noted in the video, PLA makes for a very poor spring material, so you probably want to skip that one.
We covered compliant mechanisms in the past for purposes like blasters, including some that you can only see under a microscope.
