Picture By Paper Tape

August 26, 2025 by 14 Comments

The April 1926 issue of “Science and Invention” had a fascinating graphic. It explained, for the curious, how a photo of a rescue at sea could be in the New York papers almost immediately. It was the modern miracle of the wire photo. But how did the picture get from Plymouth, England, to New York so quickly? Today, that’s no big deal, but set your wayback machine to a century ago.

Of course, the answer is analog fax. But think about it. How would you create an analog fax machine in 1926? The graphic is quite telling. (Click on it to enlarge, you won’t be disappointed.)

If you are like us, when you first saw it you thought: “Oh, sure, paper tape.” But a little more reflection makes you realize that solves nothing. How do you actually scan the photo onto the paper tape, and how can you reconstitute it on the other side? The paper tape is clearly digital, right? How do you do an analog-to-digital converter in 1926? Continue reading “Picture By Paper Tape” →

Close up of a multi-USB tester PCB

Troubled USB Device? This Tool Can Help

August 26, 2025 by 18 Comments

You know how it goes — some gadgets stick around in your toolbox far longer than reason dictates, because maybe one day you’ll need it. How many of us held onto ISA diagnostic cards long past the death of the interface?

But unlike ISA, USB isn’t going away anytime soon. Which is exactly why this USB and more tester by [Iron Fuse] deserves a spot in your toolbox. This post is not meant to directly lure you into buying something, but seen how compact it is, it would be sad to challenge anyone to reinvent this ‘wheel’, instead of just ordering it.

So, to get into the details. This is far from the first USB tester to appear on these pages, but it is one of the most versatile ones we’ve seen so far. On the surface, it looks simple: a hand-soldered 14×17 cm PCB with twelve different connectors, all broken out to labelled test points. Hook up a dodgy cable or device, connect a known-good counterpart, and the board makes it painless to probe continuity, resistance, or those pesky shorts where D+ suddenly thinks it’s a ground line.

You’ll still need your multimeter (automation is promised for a future revision), but the convenience of not juggling probes into microscopic USB-C cavities is hard to overstate. Also, if finding out whether you have a power-only or a data cable is your goal, this might be the tool for you instead.

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.

Continue reading “Where There Is No Down: Measuring Liquid Levels In Space” →

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.

Continue reading “Very Efficient APFC Circuit In Faulty Industrial 960 Watt Power Supply” →

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.