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Scratch-built Electric Boat Shows off Surprising Speed

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Electric cars are everywhere these days, but what about boats? Looking to go green on the water, [NASAT] put together this impressively nimble boat propelled by a pair of brushless motors. The boat itself has a completely custom-built hull, using plywood as a mold for the ultimate fiberglass body. Itā€™s a catamaran-like shape that seems to allow it to get on plane fairly easily, increasing its ultimate speed compared to a displacement hull. It gets up to that speed with two electric motors totaling 4 kW, mated to a belt-driven drivetrain spinning a fairly standard prop. Power is provided by a large battery, and the solar panel at the top can provide not only shade for the operator, but 300 W to charge the battery when the motors are not being used. With the finishing touches put on, the small single-seat boat effortlessly powers around the water with many of the same benefits of an electric car: low noise, low pollution, a quiet ride, and a surprisingly quick feel. Electrification h...
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Building a Cyberpunk Modular Keyboard

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Perhaps you have a tilt towards glowing cyberpunk peripherals. Perhaps youā€™ve been hunting for a keyboard that you can position perfectly to suit both your left and right hands. In that case, you might just like this nifty design from [Modern Hobbyist]. The first thing youā€™ll note is the split design, which allows each half of the keyboard to be placed optimally for each armā€™s comfort. Theyā€™re linked with a cable, which allows the STM32 microcontroller to read the keys on both sides and then spit out the right stuff upstream over its USB-C connection. The microcontroller is also in charge of running the per-key LED lighting and the LCD screens on each half. The board owes its sleek and slim design at least in part to using Kailh Choc low-profile switches. They plug in to hotswap compatible sockets so the switches can easily be changed if desired. Keycaps are blank off-the-shelf parts because this is a keyboard for those who arenā€™t afraid to spend the time establishing the right musc...
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Single Tube SDR Is a Delightful Mix of Old and New

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Software Defined Radio (SDR) is the big thing these days, and why not? A single computer can get rid of a room full of boat anchors, and give you better signal discrimination than all but the best kit. Any SDR project needs an RF receiver, and in this project [mircemk] used a single 6J1 vaccum tube to produce an SSB SDR that combines the best of old and new.  Single-tube radios are a classic hack, and where a lot of hams got started back in the day, but there is a reason more complicated circuits tend to be used. On the other hand, if you can throw a PC worth of signal processing at the output, it looks like you can get a very sensitive and selective single-sideband (SSB) receiver.  The 6J1 tube is convenient, since it can run on only 6 V (or down to 3.7 as [mircemk] demonstrates). Here it is used as a mixer, with the oscillator signal injected via the screen grid. Aside from that, the simple circuit consists of a receiving coil, a few resistors and a variable capacitor. ...
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Letā€™s Buy Commodore! Well, Somebody Is.

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When a man wearing an Atari T-shirt tells you heā€™s buying Commodore it sounds like the plot for an improbable 1980s movie in which Nolan Bushnell and Jack Tramiel do battle before a neon synthwave sunset to a pulsating chiptune soundtrack. But here on the screen thereā€™s that guy doing just that, Itā€™s [Retro Recipes], and in the video below heā€™s assembling a licensing deal for the Commodore brand portfolio from the distant descendant of the Commodore of old. Itā€™s a fascinating story and we commend him for tracing a path through the mess that unfolded for Commodore in the 1990s. We tried the same research path with a friend a few years ago and ended up with an anonymous Dutch paper company that wouldnā€™t answer our calls, so weā€™re impressed. In conjunction with several other players in the Commodore retrocomputing world heā€™s trying to assemble a favourable percentage deal for manufacturers of new parts, computers, and other goodies, and weā€™re pleased to see that itā€™s for the smaller pl...
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The Bellmac-32 CPU ā€” What?

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If you have never heard of the Bellmac-32 , you arenā€™t alone. But it is a good bet that most, if not all, of the CPUs in your devices today use technology pioneered by this early 32-bit CPU. The chip was honored with the IEEE Milestone award, and [Willie Jones] explains why in a recent post in Spectrum. The chip dates from the late 1970s. AT&Tā€™s Bell Labs had a virtual monopoly on phones in the United States, but that was changing, and the government was pressing for divestiture. However, regulators finally allowed Bell to enter the computing market. There was only one problem: everyone else had a huge head start. There was only one thing to do. There was no point in trying to catch the leaders. Bell decided to leap ahead of the pack. In a time when 8-bit processors were the norm and there were nascent 16-bit processors, they produced a 32-bit processor that ran at a ā€” for the time ā€” snappy 2 MHz. At the time (1978), most chips used PMOS or NMOS transistors, but Bellmac-32 use...
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Freeze-drying for improved metal printing

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For all the remarkable improvements weā€™ve seen in desktop 3D printers, metal printers have tended to stay out of reach for hackers, mostly because they usually rely on precise and expensive laser systems. This makes it all the more refreshing to see [Dan Gelbart]ā€™s demonstration of Rapidiaā€™s cast-to-sinter method, which goes from SLA prints to ceramic or metal models. The process began by printing the model in resin, scaled up by 19% to account for shrinkage. [Dan] then used the resin print to make a mold out of silicone rubber, after first painting the model to keep chemicals from the resin from inhibiting the siliconeā€™s polymerization. Once the silicone had set, he cut the original model out of the mold and prepared the mold for pouring. He made a slurry out of metal powder and a water-based binder and poured this into the mold, then froze the mold and its contents at -40 ā„ƒ. The resulting mixture of metal powder and ice forms a composite much stronger than pure ice, from which [Da...
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A Flip Clock Becomes a Flip Timer

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Sometimes itā€™s nice to have a widget to do a single task and avoid getting distracted by the supposed simplicity of doing it with an app on a smartphone. [Dina Amin] built a timer from an old flip clock to stay focused. Starting with a disassembly of the flip clocks she found at a flea market with [Simone Giertz], [Amin] decided to change the twenty four hour mechanism to a twenty four minute one which was similar to the amount of time she was already using for several different practices. Since sheā€™s an expert in animation, she planned on turning a set of CT scans into the animation that would play on the section that had previously been the minutes of the clock. As much of the original clockā€™s components were damaged, and [Amin] didnā€™t have a chance to learn clockmaking from scratch in a week, she tried a few different drive mechanisms for the build. The drum from an air fryer timer driven with an electric motor fit the bill, but off enough from proper minutes that [Amin] switche...
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