A coiled black USB-C to USB-C cable is shown on a white background.

An Open-Source Justification For USB Cable Paranoia

June 16, 2025 by 37 Comments

Most people know that they shouldn’t plug strange flash drives into their computers, but what about a USB cable? A cable doesn’t immediately register as an active electronic device to most people, but it’s entirely possible to hide a small, malicious microcontroller inside the shell of one of the plugs. [Joel Serna Moreno] and some collaborators have done just that with their Evil Crow Cable-Wind.

This cable comes in two variants: one USB-A to USB-C, and one with USB-C to USB-C. A tiny circuit board containing an ESP32-S3 hides inside a USB-C plug on each cable, and can carry out a keystroke injection attack. The cable’s firmware is open-source, and has an impressive set of features: a payload syntax checker, payload autocompletion, OS detection, and the ability to impersonate the USB device of your choice.

The cable provides a control interface over WiFi, and it’s possible to edit and deploy live payloads without physical access to the cable (this is where the syntax checker should be particularly useful). The firmware also provides a remote shell for computers without a network connection; the cable opens a shell on the target computer which routes commands and responses through the cable’s WiFi connection (demonstrated in the video below).

The main advantage of the Evil Crow Cable Wind is its price: only about $25, at which point you can afford to lose a few during deployment. We’ve previously seen a malicious cable once before. Of course, these attacks aren’t limited to cables and USB drives; we’ve seen them in USB-C docks, in a gaming mouse, and the fear of them in fans.

Thanks to [rustysun9] for the tip!

Balancing Robot Gallery

Cube Teeter Totter: One Motor, Many Lessons

June 16, 2025 by 5 Comments

Balancing robots are always fun to see, as they often take forms we’re not used to, such as a box standing on its corner. This project, submitted by [Alexchunlin], showcases a cool single motor reaction cube, where he dives into many lessons learned during its creation.

At the outset, [Alexchunlin] thought this would be a quick, fun weekend project, and while he achieved that, it took longer than a weekend in the end. The cube’s frame was a simple 3D print with provisions to mount his MotorGo AXIS motor controller. This motor controller was initially designed for another project, but it’s great to see him reuse it in this build.

Once the parts were printed and assembled, the real work began: figuring out the best way to keep the cube balanced on its corner. This process involved several steps. The initial control code was very coarse, simply turning the motor on and off, but this didn’t provide the fine control needed for delicate balancing. The next step was implementing a PID control loop, which yielded much better results and allowed the cube to balance on a static surface for a good amount of time. The big breakthrough came when moving from a single PID loop to two control loops. In this configuration, the PID loop made smaller adjustments, while another control loop focused on the system’s total energy, making the cube much more stable.

By the end of the build, [Alexchunlin] had a cube capable of balancing in his hand, but more importantly, it was a great learning experience in controls. Be sure to visit the project page for more details on this build and check out his video below, which shows the steps he took along the way. If you find this project interesting, be sure to explore some of our other featured reaction wheel projects.

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Capacitor Adapter board

Kludge Compensates For Kaput Component With Contemporary Capacitor

June 16, 2025 by 14 Comments

It is a well-known reality of rescuing certain older electronic devices that, at some point, you’re likely going to have to replace a busted capacitor. This is the stage [Kevin] is at in the 3rd installment in his saga of reviving a 50-year-old Military Tektronix oscilloscope.

[Kevin] recently discovered a failed capacitor in the power supply for this vintage analog scope. Having identified and removed the culprit, it was time to find a way to replace the faulty component with a modern equivalent. The original capacitor is out of fashion to the degree that a perfect replacement would be impractical and likely not desirable. This job would call for a bit of adaptation.

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Retrotechtacular: Arthur C. Clarke Predicts The Future

June 16, 2025 by 22 Comments

Predicting the future is a dangerous occupation. Few people can claim as much success as Arthur C. Clarke, the famous science and science fiction author. Thanks to the BBC and the Australian Broadcasting Company, we can see what Sir Arthur thought about the future in 1964 and then ten years later in 1974.

Perhaps his best-known prediction was that of communication satellites, but he called quite a few other things, too. Like all prognosticators, he didn’t bat a thousand, and he missed a wrinkle or two, but overall, he has a very impressive track record.

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Expanding rack structure

Expanding Racks In The Spirit Of The Hoberman Sphere

June 16, 2025 by 7 Comments

If you’re a mechanical engineering wonk, you might appreciate this latest video from [Henry Segerman] wherein he demonstrates his various expanding racks.

[Henry] explains how the basic “double-rack” unit can be combined to make more complex structures. These structures are similar in spirit to the Hoberman sphere, which is a compact structure that can be expanded to fill a large space.

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Big Chemistry: Seawater Desalination

June 16, 2025 by 40 Comments

For a world covered in oceans, getting a drink of water on Planet Earth can be surprisingly tricky. Fresh water is hard to come by even on our water world, so much so that most sources are better measured in parts per million than percentages; add together every freshwater lake, river, and stream in the world, and you’d be looking at a mere 0.0066% of all the water on Earth.

Of course, what that really says is that our endowment of saltwater is truly staggering. We have over 1.3 billion cubic kilometers of the stuff, most of it easily accessible to the billion or so people who live within 10 kilometers of a coastline. Untreated, though, saltwater isn’t of much direct use to humans, since we, our domestic animals, and pretty much all our crops thirst only for water a hundred times less saline than seawater.

While nature solved the problem of desalination a long time ago, the natural water cycle turns seawater into freshwater at too slow a pace or in the wrong locations for our needs. While there are simple methods for getting the salt out of seawater, such as distillation, processing seawater on a scale that can provide even a medium-sized city with a steady source of potable water is definitely a job for Big Chemistry.

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This Thermochromic Clock Is A Ray Of Sunshine

June 16, 2025 by 5 Comments

It’s never a bad time to look at a clock, and one could certainly do worse than this delightful Paper Sunshine Clock by [anneosaur]. The sun-ray display is an interesting take on the analog clock, and its method of operation is not one we see every day, either.

Reading the clock is straightforward: there are twelve rays divided into two segments. Once you figure out that this artful object is a clock, it’s easy enough to guess that the rays give the hours, and half-rays are half-hours. In the photo above, it’s sometime between nine o’clock and nine thirty. Our Swiss readers might not be terribly impressed, but a “fuzzy” clock like this is quite good enough much of the time for many people.

Even the flex PCB holding the resistors looks like a work of art.

The title gives away its method of operation: it’s thermochromic paint! The paint is printed onto a piece of Japanese awagami paper, which is pressed against a flexible PCB holding an array of resistors. Large copper pads act as heat spreaders for the resistors. For timekeeping and control, an Atmega328PB is paired with a DS3231MZ RTC, with a coin cell for backup power when the unit is unplugged. (When plugged in, the unit uses USB-C, as all things should.) That’s probably overkill for a +/-30 minute display, but we’re not complaining.

The Atmega328PB does not have quite enough outputs to drive all those resistors, so a multiplexing circuit is used to let the 10 available GIPO control current to 24 rays. Everything is fused for safety, and [anneosaur] even includes a temperature sensor on the control board. The resistors are driven by a temperature-compensated PWM signal to keep them from overheating or warming up too slowly, regardless of room temperature. The attention to detail here is as impressive as the aesthetics.

[annenosaur] has even thought of those poor people for whom such a fuzzy clock would never do (be they Swiss or otherwise) — the Paper Sunshine Clock has a lovely “sparkle mode” that turns the rays on and off at random, turning the clock into an art piece. A demo video of that is below. If you find this clock to be a ray of sunshine, everything you need to reproduce it is on GitHub under an MIT or CC4.0 license.

This is not the first thermochromic clock we’ve featured, though the last one was numeric. If you must have minute accuracy in a thermochromic analog clock, we’ve got you covered there, too.

Special thanks to [anneosaur] for submitting the hack. If you’ve seen (or made) a neat clock, let us know! You won’t catch us at a bad time; it’s always clock time at Hackaday.