Kritik sah

Producing hot water off-grid is a surprisingly energy-intensive activity, and although it looks simple on its surface it can get quite complicated especially when used in large scale for something like providing hot water for an entire home. When using combustion to heat the water there needs to be proper venting as well as control of the fuel, and even storage of the hot water needs to be meticulous to avoid certain pathogens. [Greenhill Forge] has built an off-grid solution for heating hot water that doesn’t necessarily rely on any combustion , though, provided he can find something to spin his custom electric machine. The machine in question is, of course, an induction heater. It works similar to any simple electric motor, generator, or transformer except in this case the eddy currents generated are exploited rather than minimized. Normally these currents, generated when a magnet passes by a metal, are wasted heat in other machines but in this induction heater it’s the g...

You can get all kinds of fancy lenses for modern cameras, with all sorts of mechanical and electronic wizardly to make them shoot better images. But what if you paired a vintage lens with a modern camera? It would take some work, as [Mathieu] found out, but you’d also get some interesting results. The optic in question is a 100-year old lens—a Foth 50 mm f2.5 to be precise, originally used with a folding film camera. It was sourced from a market for just 3 euros. Notably, the lens was not designed for modern cameras, and so lacks an aperture and focusing mechanism. [Mathieu] thus had to fabricate something to fit the lens to a Sony FX3. A first attempt used an aperture adapter from Amazon and an elcoid adapter, but there were vignetting problems due to the lens placement in this case. Ultimately, [Mathieu] went with a special macro adapter that allowed him to control focus and tuck in an ND filter behind the lens, which made up for the lack of an aperture. The vintage glass isn...

Before Linux, there was Unix. It was great, but it was and has been plagued by problems with licensing and proprietary competition. [Vintage Appartus] recalls, for example, the AT&T Unix PC from the 1980s. It was awesome, but you’ve probably never heard of it. For 1985, it was a nice setup. You got a 10 MHz Motorola 68010, 512K of RAM (but upgradable to 4M), a floppy, a modem, a 720×384 monochrome screen, and a 10 or 20 MB hard drive. You can check out the video explaining the machine and its problems below. Physically, the computer looked like a high-end Apple ][ with a removable keyboard and a built-in monitor. Expansion was via three slots. Cold start took about three minutes, and then you have a fairly normal Unix setup for the period. The sample machine uses a disk emulator, so the video shows the computer running much faster than it would with a real period hard drive. The card also has an 8086 expansion board that can boot MSDOS, an important feature in 1985. ...

Normally, when you design an electronic gadget, you worry about how hot it will get. Automotive-grade components, for example, often have higher allowable temperatures than commercial parts. However, extremely cold environments, such as deep space or the interiors of quantum computers, are also challenging. Researchers at King Abdullah University of Science and Technology believe gallium oxide may be key to operating near absolute zero. According to [Vishal Khandelwal], one of the researchers, most conventional electronics fail below -173C or 100K. Quantum computers routinely operate at 4K. However, β-Ga 2 O 3 is a wide-bandgap semiconductor that has low current leakage and works at high temperatures up to 500C. However, it also avoids the freeze-out effect that traps electrons in other semiconductor materials. The team built two devices from the material seeded with a silicon dopant. The first was a FET with a fin-shaped geometry. The second was an inverter. Both operated reliabl...

Back when phones used to ship with chargers in the box, you’d get a plugpack that could charge one device. Aftermarket manufacturers eventually started making chargers with four or five ports which were great for travelling. But what if you wanted to charge even more devices? You might build something like this rig from [DENKI OTAKU]. The goal was to build a charger that could handle 100 devices at once. The charger is designed to charge devices at up to 1.5 amps. That’s no mean feat, as the device would have to be able to deliver 150 amps total when fully loaded. As for the actual design, though, it’s relatively simple. [DENKI OTAKU] simply built a simple USB-C charger PCB based around an off-the-shelf chip which has ten individual chargers on it, and stacked it up ten of those in a housing made out of aluminium extrusion. To deliver the current to run all these chargers, the rig got two massive switching power supplies to feed the charger array a massive amount of c...

Simple paper hinge. (Credit: Itoshige Studio, YouTube) One doesn’t generally associate cardboard with structural components like hinges, but [Itoshige Studio] assures us that you can absolutely create hinges out of this ubiquitous material . In total the video covers five different designs, ranging from the simple and straightforward to an interlocking tab design that approximates a typical steel hinge with paper rod to keep both sides of the hinge together. The most simple hinge is unsurprisingly just a strip of craft paper, which is also demonstrated as the hinge for a wooden box in lieu of the typical metal hinge. This same principle is then demonstrated for a fancy cardboard box. From here the hinge designs increasingly get more involved, with first a seamless hinge variation, and then a kamichoban hinge design that’s inspired by traditional Japanese room dividers and furniture, using panels that are interconnected with overlapping sections to create a fascinatingly f...