Making A Robot To Serve Some Mean Badminton Shuttlecocks

August 30, 2026 by Maya Posch 2 Comments

Sometimes regarded as a less violent form of tennis, badminton is still a pretty challenging sport. One which suffers like so many sports from requiring at least two players since magically flying balls and shuttlecocks haven’t been invented yet. After years of tinkering on a shuttlecock serving robot, [Travis Mitchell] hit upon the idea to convert a small industrial robotic arm for the purpose.

The target of this conversion is a positively cute-sized Denso VS050 robotic arm, with Denso helpfully providing a 3D model of the arm as a solid jumping-off point in a CAD project. Here the task of the robotic arm is two-fold: one is to grab a fresh shuttlecock from a hopper with a pneumatic grabber, the other is to feed it into the spinning wheels that grip and launch it. Fortunately [Travis] has a pretty tricked-out workshop available, including the ability to 3D print metal parts, making building the prototype a snap.

After initially thinking of using a Raspberry Pi Pico, he ended up using an ATmega AVR due to the input-output requirements when communicating with the arm. Using a height-adjustable desk as the base, the whole assembly was put together for some testing on the badminton court.

With most of the testing having been done in the shop already, the remaining issue was to determine the best disc material, as the two high-speed discs that grip the shuttlecock must be well-balanced and not stretch too much. Ultimately a 3D printed plastic disc with a silicone strip as gripping surface was found to work pretty well, allowing for the robot to finally start serving its function.

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Dissecting A Lethal Universal Travel Adapter

August 30, 2026 by Maya Posch 52 Comments

The world’s refusal to standardize on a single type of mains power outlet has led to a vibrant market of so-called travel adapters, all of which try to outdo each other in convenience and universality. This comes at the cost of complexity, something which ultimately reflects in the price. The cheapo $9.26 universal travel adapter that [Brainiac 75] got off an online retailer’s site is thereby a good example of how safety suffers if the overarching goal is to ‘make it cheap’.

The first exciting discovery is that when you plug any of its three sets of connectors into an outlet, the others become live at the same voltage. This would suggest that they’re just wired together, a fact soon confirmed with a quick resistance check between the respective prongs. Though to the adapter’s credit, the prongs are not live when fully retracted into the enclosure. Yet as demonstrated in the video, the retracting of prongs is not enforced, so mistakes here are possible.

The adapter also has two USB ports that claim to provide 5 V at 2.1 A, with as it turns out no hard cut-off. This is probably the best part of the adapter despite not featuring any advanced charging features. After opening the adapter, you can see that the sliding mains prongs connect to a central bus bar when either unfolded or extended, which is definitely straightforward, but doesn’t enforce that only one type of prongs can be used at any given time.

To make it safer, [Brainiac75] removed the less useful US and UK plugs, taping over the empty holes. It’s now just a USB charger with a universal mains port to plug random non-EU plugs into, which is probably relatively safe and a better idea than really using it as a travel adapter.

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Giving The NES An Optical Data Storage Add-On

August 30, 2026 by Maya Posch 10 Comments

The introduction of optical media in the form of CDs meant a revolution in the world of gaming consoles, escaping the restrictions of a few dozen MB of storage and instead offering a theoretically infinite amount of storage through the miracle and tedium of swapping discs. After the SNES narrowly escaped getting a CD add-on and the N64 doubled down on cartridges, we can now at least get an impression of what it’d be like if the Nintendo Entertainment System had been gifted a CD add-on back in the 1980s, courtesy of a project by [Throaty Mumbo].

The NES future we could have had. (Credit: Throaty Mumbo, YouTube) — The NES future we could have had.

There’s also an accompanying video containing typical hijinks and a demonstration of this system. Initially [Throaty Mumbo] was going to make a SNES CD add-on to match that console’s initial prototype, but doing it for the NES seemed more fun. Obviously, since the NES is quite limited hardware-wise it was always going to be a struggle, even if the original front-loading NES conveniently has a mostly unused expansion slot.

On the custom PCB there is an RP2350B microcontroller that mediates between an Everdrive N8 Pro cartridge and an IDE CD drive, along with a PCM5102 audio DAC. The expansion port is hereby used to receive the audio samples on its audio mix input pin, along with power. After boot the game ROM is read off the CD by the MCU and streamed over USB to the Everdrive.

Combined with the previous work [Throaty Mumbo] did to revive the long-defunct Japanese online service for the NES, it’s an exciting time for fans of the iconic console.

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Reviving An SD Card With Shorted Capacitors

August 28, 2026 by Maya Posch 19 Comments

A nice thing about SD cards is that even in their non-micro format they are conveniently small. This is however a bit of a problem when an SD card stops working, as they are not exactly designed to be easy to service, or to recover data from. There is however a very good chance that the Flash memory and controller are still fine, and it’s actually one of the passives on the tiny PCB that failed, as with the 32 GB SD card that [Yevgeniy Kapishon] recently diagnosed and recovered data from for a customer.

Tiny capacitors in an SD card package. (Credit: Aeson Labs)

A big hint during initial diagnostics was a clear short between the supply rail and ground, but as became clear when taking the SD card apart, this one was built as a monolithic package, without exposed components on a PCB as in older SD cards. Correspondingly an X-ray machine and thermal camera were used to figure out what was inside the package, and where the short was located.

By combining the hot spot image with the X-ray it was determined that the problem was with some passives near the edge of the package. Some careful material removal later two miniscule capacitors were found to be the culprit and gently removed. With this the short on the power rail vanished, and the SD card started working again.

Having a shorted MLCC or similar passive component is a very common failure mode in general which can cripple even the most expensive device. Even if SD cards still aren’t really repairable, it’s at least reassuring to know that in many cases the data is fairly easy to recover once you have identified and removed the offending part.

Casting Engine Parts From 3D Prints

August 28, 2026 by Maya Posch 28 Comments

After building a couple of internal combustion engines by milling billet aluminium stock and cringing at the absolute waste of material this created, [Camden Bowen] figured he’d give casting metal parts a shot. Of course, the key here is to create the molds for said casting, which is where you got a few options available.

Since DIY is really his thing, he also made his own kiln using cement and perlite, plus a propane burner. For the aluminium material to melt, he bought a stack of aluminium alloy wheels, as these are made of an alloy that’s actually suitable for casting. These were turned into ingots as a first step towards casting the engine parts, which among other things helps to purify the metal.

For the actual casting method he picked lost PLA, meaning the intended shape is 3D printed in PLA, then put into plaster before it’s melted out of the newly minted mold in an oven and subsequently burned out in the kiln. For the plaster [Camden] used regular Plaster of Paris, mixed with sand to give it suitable heat-resistant properties.

After some trial and error, as well as a lot of trouble burning out all the PLA, he got a usable mold and managed to eventually cast an engine cylinder with only a few imperfections. Considering just how convoluted it would have been to mill that part out of billet aluminium, it’s easy to see why commercial manufacturers are casting such parts as well.

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Running Multiple Linux Kernels Without Hypervisor

August 27, 2026 by Maya Posch 15 Comments

In a move that’s no doubt going to trigger a lot of confusion and nostalgia, Mklinux is back, in a sense. As the announcement makes clear, this is multikernel Linux, not microkernel Linux, which is an experimental OS designed to run the Linux kernel as a user-space server running on top of OS X’s Mach kernel.

Naming overlap niggles aside, this neo-mklinux lets multiple independent Linux kernels run simultaneously on bare metal. There is still a host kernel which handles the carving up of hardware resources to the newly spawned kernels, but unlike with a hypervisor there are no abstraction or translation layers.

In theory this should mean basically perfect isolation between kernels, which is one of the main selling points along with increased performance. Compared to running KVM guests the provided benchmarks show much lower latency, at between parity to two times faster.

A website is provided with instructions to get started, along with architectural details if that’s your thing.

The Mactini: A Computer That Does Almost Nothing

August 27, 2026 by Maya Posch 13 Comments

Recently [Tucker Osman] brought to life what once was just a meme created by the BBC as it poked fun at Apple’s push for ever smaller devices that also dropped many features along the path towards questionable innovation. This ‘Mactini’ was a super-small laptop, with just a single button that did everything, befitting the overpriced more-money-than-sense status symbol vibe that [Jony Ive] brought to Apple.

The input method suggested in the BBC video involves convoluted patterns using the single button, which would be functional, albeit cumbersome. Even as [Tucker] set out on this mission to make the Mactini real, he had to answer a lot of questions, while sticking to the rules that it had to follow the rough form factor of the original and have the same features.

In lieu of overcomplicating things, he opted to use a 1.69″ ST7789V2-based SPI LCD along with a small RP2350-based board from Waveshare for the brains. Rather than just slapping the LCD example for the Pico board on it as firmware, he actually used DMA to do the screen data copying, freeing up a lot of CPU cycles.

The rest of the hardware was cobbled together from e-waste parts, including an iPad speaker and an audio amplifier from a scrap board. Video was handled using Motion JPEG decoding for a not-horrible-framerate. All of this was put into a 3D printed case that was designed in FreeCAD, to make the Mac that [Ive] could only have dreamed of back in the 2000s.

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