Author: Lewin Day

3486 Articles

Hydrofoil Bikes Are Harder To Build Than You Think

November 27, 2025 by 7 Comments

Hydrofoils are perhaps best known for their application on boring ferries and scary boats that go too fast. However, as [RCLifeOn] demonstrates, you can also use them to build fun and quirky personal watercraft. Like a hydrofoil bike! Only, there are some challenges involved.

Hydrofoils work much like airfoils in air. The shape of the foil creates lift, raising the attached vehicle out of the water. This allows the creation of a craft that can travel more quickly because the majority of its body is not subject drag from the water. The key is to design the craft such that the hydrofoils remain at the right angle and depth to keep the craft lifted out of the water while remaining stable.

The hydrofoil bike is created out of a combination of plywood, foam, and 3D printed components. It uses a powerful brushless motor for propulsion, and that’s about it. Sadly, despite the simplicity, it wasn’t an instant success. As you might expect, balancing on the bike is quite difficult, particularly when trying to get it started—as the foils need some speed to actually start generating meaningful lift.

After further research into commercial hydrofoil bikes, [RCLifeOn] realized that the buoyancy of the bike made it too hard to straddle when starting out. Some of the 3D printed foils also proved more than a little fragile. It’s back to the drawing board for now—the power system is likely up to snuff, but the dynamics of the platform need work. It’s perhaps no surprise; we’ve covered the challenges of hydrofoil stability before. If you want to go fast on water, you could go the easier route and just build an electric surfboard. Video after the break.

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One-Way Data Extraction For Logging On Airgapped Systems

November 27, 2025 by 51 Comments

If you want to protect a system from being hacked, a great way to do that is with an airgap. This term specifically refers to keeping a system off any sort of network or external connection — there is literally air in between it and other systems. Of course, this can be limiting if you want to monitor or export logs from such systems. [Nelop Systems] decided to whip up a simple workaround for this issue, creating a bespoke one-way data extraction method.

The concept is demonstrated with a pair of Raspberry Pi computers. One is hooked up to critical industrial control systems, and is airgapped to protect it against outside intruders. It’s fitted with an optocoupler, with a UART hooked up to the LED side of the device. The other side of the optocoupler is hooked up to another Raspberry Pi, which is itself on a network and handles monitoring and logging duties.

This method creates a reliable one-way transmission method from the airgapped machine to the outside world, without allowing data to flow in the other direction. Indeed, there is no direct electrical connection at all, since the data is passing through the optocoupler, which provides isolation between the two computers. Security aficionados will argue that the machine is no longer really airgapped because there is some connection between it and the outside world. Regardless, it would be hard to gain any sort of access through the one-way optocoupler connection. If you can conceive of a way that would work, drop it down in the comments.

Optocouplers are very useful things; we’ve seen them used and abused for all sorts of different applications. If you’ve found some nifty use for these simple parts, be sure to drop us a line!

Google Is Building A New OS

November 27, 2025 by 67 Comments

Windows, macOS, and Linux are the three major desktop OSs in today’s world. However, there could soon be a new contender, with Google stepping up to the plate (via The Verge).

You’ve probably used Google’s operating systems before. Android holds a dominant market share in the smartphone space, and ChromeOS is readily available on a large range of notebooks intended for lightweight tasks. Going forward, it appears Google aims to leverage its experience with these products and merge them into something new under the working title of “Aluminium OS.”

The news comes to us via a job listing, which sought a Senior Product Manager to work on a “new Aluminium, Android-based, operating system.” The hint is in the name—with speculation that the -ium part of Aluminium indicates its relationship to Chromium, the open-source version of Chrome. The listing also indicated that the new OS would have “Artificial Intelligence (AI) at the core.” At this stage, it appears Google will target everything from cheaper entry level hardware to mid-market and premium machines.

It’s early days yet, and there’s no word as to when Google might speak more officiously on the topic of its new operating system. It’s a big move from one of the largest tech companies out there. Even still, it will be a tall order for Google to knock off the stalwart offerings from Microsoft and Apple in any meaningful way. Meanwhile, if you’ve got secret knowledge of the project and they forget to make you sign an NDA, don’t hesitate to reach out!

A Friendly Reminder That Your Unpowered SSDs Are Probably Losing Data

November 26, 2025 by 48 Comments

Save a bunch of files on a good ol’ magnetic hard drive, leave it in a box, and they’ll probably still be there a couple of decades later. The lubricants might have all solidified and the heads jammed in place, but if you can get things moving, you’ll still have your data. As explained over at [XDA Developers], though, SSDs can’t really offer the same longevity.

It all comes down to power. SSDs are considered non-volatile storage—in that they hold on to data even when power is removed. However, they can only do so for a rather limited amount of time. This is because of the way NAND flash storage works. It involves trapping a charge in a floating gate transistor to store a single bit of data. You can power down an SSD, and the trapped charge in all the NAND flash transistors will happily stay put. But over longer periods of time, from months to years, that charge can leak out. When this happens, data is lost.

Depending on your particular SSD, and the variety of NAND flash it uses (TLC, QLC, etc), the safe storage time may be anywhere from a few months to a few years. The process takes place faster at higher temperatures, too, so if you store your drives in a warm area, you could see surprisingly rapid loss.

Ultimately, it’s worth checking your drive specs and planning accordingly. Going on a two-week holiday? Your PC will probably be just fine switched off. Going to prison for three to five years with only a slim chance of parole? Maybe back up to a hard drive first, or have your cousin switch your machine on now and then for safety’s sake.

On a vaguely related note, we’ve even seen SSDs that can self-destruct on purpose. If you’ve got the low down on other neat solid-state stories, don’t hesitate to notify the tipsline.

Benchmarking Chinese CPUs

November 26, 2025 by 25 Comments

When it comes to PCs, Westerners are most most familiar with x86/x64 processors from Intel and AMD, with Apple Silicon taking up a significant market share, too. However, in China, a relatively new CPU architecture is on the rise. A fabless semiconductor company called Loongson has been producing chips with its LoongArch architecture since 2021. These chips remain rare outside China, but some in the West have been benchmarking them.

[Daniel Lemire] has recently blogged about the performance of the Loongson 3A6000, which debuted in late 2023. The chip was put through a range of simple benchmarking tests, involving float processing and string transcoding operations. [Daniel] compared it to the Intel Xeon Gold 6338 from 2021, noting the Intel chip pretty much performed better across the board. No surprise given its extra clock rate. Meanwhile, the gang over at [Chips and Cheese] ran even more exhaustive tests on the same chip last year. The Loongson was put through typical tasks like  compressing archives and encoding video. The outlet came to the conclusion that the chip was a little weaker than older CPUs like AMD’s Zen 2 line and Intel’s 10th generation Core chips. It’s also limited as a four-core chip compared to modern Intel and AMD lines that often start at 6 cores as a minimum.

If you find yourself interested in Loongson’s product, don’t get too excited. They’re not exactly easy to lay your hands on outside of China, and even the company’s own website is difficult to access from beyond those shores. You might try reaching out to Loongson-oriented online communities if you seek such hardware.

Different CPU architectures have perhaps never been more relevant, particularly as we see the x86 stalwarts doing battle with the rise of desktop and laptop ARM processors. If you’ve found something interesting regarding another obscure kind of CPU, don’t hesitate to let the tipsline know!

Chinese Regulators May Kill Retractable Car Door Handles That Never Should Have Existed

November 26, 2025 by 157 Comments

Headlights. Indicators. Trunk releases. Seatbelts. Airbags. Just about any part of a car you can think of is governed by a long and complicated government regulation. It’s all about safety, ensuring that the car-buying public can trust that their vehicles won’t unduly injure or maim them in regular operation, or in the event of accident.

However, one part of the modern automobile has largely escaped regulation—namely, the humble door handle. Automakers have been free to innovate with new and wacky designs, with Tesla in particular making waves with its electronic door handles. However, after a series of deadly incidents where doors wouldn’t open, regulators are now examining if these door handles are suitable for road-going automobiles. As always, regulations are written in blood, but it raises the question—was not the danger of these complicated electronic door handles easy to foresee?

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Build A High Voltage Supply For Vacuum Tube Work

November 25, 2025 by 12 Comments

If you work on simple digital projects, just about any bench supply will offer the voltage and current you’re looking for. However, if you’re working with valves, you’ll often find yourself needing much higher voltages that can be tricky to source. [Chappy Happy] has shared a design for a simple HV power supply that should prove useful to vacuum tube enthusiasts.

The build is fairly basic in nature, lacing together some commonly available parts to generate the necessary voltages for working with common vacuum tubes from a 12 volt DC input. Inside the supply is a UC3843A DC boost converter, set up to output high voltage up to around 300 volts DC, with a ripple filter added for good measure. The output can be adjusted with a knob, with a voltmeter on the front panel. There’s also a 12-volt output, and a LM2596 step down converter to produce 6.3 volts for the filament supply. The whole project is built in an old Heathkit project box, and he demonstrates the supply with a simple single-tube amplifier.

If you find yourself regularly whipping up tube circuits, you might like to have something like this on your workbench. Or, you might even consider cooking up your own tubes from scratch if you’re more adventurous like that. Video after the break.

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