Where There Is No Down: Measuring Liquid Levels In Space

August 26, 2025 by 40 Comments

As you can probably imagine, we get tips on a lot of really interesting projects here at Hackaday. Most are pretty serious, at least insofar as they aim to solve a specific problem in some new and clever way. Some, though, are a little more lighthearted, such as a fun project that came across the tips line back in May. Charmingly dubbed “pISSStream,” the project taps into NASA’s official public telemetry stream for the International Space Station to display the current level of the urine tank on the Space Station.

Now, there are a couple of reactions to a project like this when it comes across your desk. First and foremost is bemusement that someone would spend time and effort on a project like this — not that we don’t appreciate it; the icons alone are worth the price of admission. Next is sheer amazement that NASA provides access to a parameter like this in its public API, with a close second being the temptation to look at what other cool endpoints they expose.

But for my part, the first thing I thought of when I saw that project was, “How do they even measure liquid levels in space?” In a place where up and down don’t really have any practical meaning, the engineering challenges of liquid measurement must be pretty interesting. That led me down the rabbit hole of low-gravity process engineering, a field that takes everything you know about how fluids behave and flushes it into the space toilet.

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One of the photo-detector spheres of ARCA (Credit: KM3NeT)

Confirmation Of Record 220 PeV Cosmic Neutrino Hit On Earth

August 26, 2025 by 11 Comments

Neutrinos are exceedingly common in the Universe, with billions of them zipping around us throughout the day from a variety of sources. Due to their extremely low mass and no electric charge they barely ever interact with other particles, making these so-called ‘ghost particles’ very hard to detect. That said, when they do interact the result is rather spectacular as they impart significant kinetic energy. The resulting flash of energy is used by neutrino detectors, with most neutrinos generally pegging out at around 10 petaelectronvolt (PeV), except for a 2023 event.

This neutrino event which occurred on February 13th back in 2023 was detected by the KM3NeT/ARCA detector and has now been classified as an ultra-high energy neutrino event at 220 PeV, suggesting that it was likely a cosmogenic neutrinos. When we originally reported on this KM3-230213A event, the data was still being analyzed based on a detected muon from the neutrino interaction even, with the researchers also having to exclude the possibility of it being a sensor glitch.

By comparing the KM3-230213A event data with data from other events at other detectors, it was possible to deduce that the most likely explanation was one of these ultra-high energy neutrinos. Since these are relatively rare compared to neutrinos that originate within or near Earth’s solar system, it’ll likely take a while for more of these detection events. As the KM3NeT/ARCA detector grid is still being expanded, we may see many more of them in Earth’s oceans. After all, if a neutrino hits a particle but there’s no sensor around to detect it, we’d never know it happened.

Top image: One of the photo-detector spheres of ARCA (Credit: KM3NeT)

VIC-20 Gets ISA Slot, Networking

August 26, 2025 by 22 Comments

There are few computing collapses more spectacular than the downfall of Commodore, but its rise as a home computer powerhouse in the early 80s was equally impressive. Driven initially by the VIC-20, this was the first home computer model to sell over a million units thanks to its low cost and accessibility for people outside of niche markets and hobbyist communities.

The VIC-20 would quickly be eclipsed by the much more famous Commodore 64, but for those still using these older machines there are a few tweaks to give it some extra functionality it was never originally designed for like this build which gives it an ISA bus.

To begin adapting the VIC-20 to the ISA standard, [Lee] built a fixed interrupt line handled with a simple transistor circuit. From there he started mapping memory and timing signals. The first attempt to find a portion of memory to use failed as it wasn’t as unused as he had thought, but eventually he settled on using the I/O area instead although still had to solve some problems with quirky ISA timing. There’s also a programmable logic chip which was needed to generate three additional signals for proper communication.

After solving some other issues around interrupts [Lee] was finally able to get the ISA bus working, specifically so he could add a 3Com networking card and get his VIC-20 on his LAN. Although the ISA bus has since gone out of fashion on modern computers, if you still have a computer with one (or build one onto your VIC-20), it is a surprisingly versatile expansion port.

Thanks to [Stephen] for the tip!

Very Efficient APFC Circuit In Faulty Industrial 960 Watt Power Supply

August 25, 2025 by 2 Comments

The best part about post-mortem teardowns of electronics is when you discover some unusual design features, whether or not these are related to the original fault. In the case of a recent [DiodeGoneWild] video involving the teardown of an industrial DIN-rail mounted 24 V, 960 Watt power supply, the source of the reported bang was easy enough to spot. During the subsequent teardown of this very nicely modular PSU the automatic power factor correction (APFC) board showed it to have an unusual design, which got captured in a schematic and is explained in the video.

Choosing such a APFC design seems to have been done in the name of efficiency, bypassing two of the internal diodes in the bridge rectifier with the external MOSFETs and ultrafast diodes. In short, it prevents some of the typical diode voltage drops by removing diodes in the path of the current.

Although not a new design, as succinctly pointed out in the comments by [marcogeri], it’s explained how even cutting out one diode worth of voltage drop in a PSU like this can save 10 Watt of losses. Since DIN rail PSUs rarely feature fans for active cooling, this kind of APFC design is highly relevant and helps to prevent passively cooled PSUs from spiraling into even more of a thermal nightmare.

As for the cause behind the sooty skid marks on one of the PCBs, that will be covered in the next video.

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The Shady School

August 25, 2025 by 8 Comments

We can understand why shaderacademy.com chose that name over “the shady school,” but whatever they call it, if you are looking to brush up on graphics programming with GPUs, it might be just what you are looking for.

The website offers challenges that task you to draw various 2D and 3D graphics using code in your browser. Of course, this presupposes you have WebGPU enabled in your browser which means no Firefox or Safari. It looks like you can do some exercises without WebGPU, but the cool ones will need you to use a Chrome-style browser.

You can search by level of difficulty, so maybe start with “Intro” and try doing “the fragment shader.” You’ll notice they already provide some code for you along with a bit of explanation. It also shows you a picture of what you should draw and what you really drew. You get a percentage based on the matching. There’s also a visual diff that can show you what’s different about your picture from the reference picture.

We admit that one is pretty simple. Consider moving on to “Easy” with options like “two images blend,” for example. There are problems at every level of difficulty. Although there is a part for compute shaders, none seem to be available yet. Too bad, because that’s what we find most interesting. If you prefer a different approach, there are other tutorials out there.

The camera, lens off to show the 1" sensor.

There’s Nothing Mini About This Mini Hasselblad-Style Camera’s Sensor

August 25, 2025 by 10 Comments

When someone hacks together a digital camera with a Raspberry Pi, the limiting factor for serious photography is usually the sensor. No offense to the fine folks at the foundation, but even the “HQ” camera, while very good, isn’t quite professional grade. That’s why when photographer [Malcolm Wilson] put together this “Mini Hasselblad” style camera, he hacked in a 1″ sensor.

The sensor in question came in the form of a OneInchEye V2, from [Will Whang] on Tindie. The OneInch Eye is a great project in its own right: it takes a Sony IMX283 one-inch CMOS image sensor, and packages it with an IMU and thermal sensor on a board that hooks up to the 4-lane MIPI interface on the Raspberry Pi CM4 and Pi 5.

Sensor in hand, [Malcolm] needed but to figure out power and view-finding. Power is provided by a Geekworm X1200 battery hat. That’s the nice thing about the Pi ecosystem: with so many modules, it’s like LEGO for makers. The viewfinder, too, uses 4″ HDMI screen sold for Pi use, and he’s combined it with a Mamiya C220 TLR viewfinder to give that look-down-and-shoot effect that gives the project the “Mini Hasselblad” moniker.

These are a few images [Malcom] took with the camera. We’re no pros, but at least at this resolution they look good.
The steel-PLA case doesn’t hurt in that regard either, with the styling somewhat reminiscent of vintage film cameras. The “steel” isn’t just a colour in this case, and the metal actually makes the PLA conductive, which our photographer friend learned the hard way. Who hasn’t fried components on a surface they didn’t realize was conductive, though? We bet the added weight of the steel in the PLA makes this camera much nicer to hold than it would be in plain plastic, at least.

The OneInchEye module came set up for C-mount lenses, and [Malcolm] stuck with that, using some Fujinon TV lenses he already had on hand. [Malcolm] has released STL files of his build under a Creative Commons NonCommercial license, but he’s holding the code back for subscribers to his Substack.

This isn’t the first Pi-based camera we’ve seen from [Malcolm], and there’ve been quite a few others on these pages over the years. There was even a Hackaday version, to test out the “official” module [Malcolm] eschewed.

Butta Melta Stops Rock-solid Butter From Tearing Your Toast

August 25, 2025 by 53 Comments

Ever ruin a perfectly serviceable piece of toast by trying (and failing) to spread a little pat of rock-solid butter? [John Dingley] doesn’t! Not since he created the Butta Melta to cozily snug a single butter serving right up against a warm beverage, softening it just enough to get nice and spreadable. Just insert one of those foil-wrapped pats of butter into the Melta, hang its chin on the edge of your mug, and you’ll have evenly softened butter in no time.

The Butta Melta is intentionally designed with a bit of personality, but also has features we think are worth highlighting. One is the way it’s clearly designed with 3D printing in mind, making it an easy print on just about any machine in no time at all. The second is the presence of the hinge point which really helps the Butta Melta conform to a variety of cup designs, holding the payload as close as possible to the heat regardless of cup shape. A couple of minutes next to a hot beverage is all it takes for the butter to soften enough to become easily spreadable.

You may remember [John] (aka [XenonJohn]) from his experimental self-balancing scooters, or from a documentary he made about domestic ventilator development during COVID. He taught himself video editing and production to make that, and couldn’t resist using those skills to turn a video demo of the Butta Melta into a mock home shopping style advertisement. Watch it below, embedded just under the page break, then print one and save yourself from the tyranny of torn toast.

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