These days, you have a certain expectation for computer keys on a keyboard. Of course, there are variations and proponents of different mechanisms and noise levels. However, back in the late part of the 20th century, it was a different world. Computers came with a bewildering and sometimes befuddling array of keyboards. Since the IBM Selectric was the king of typewriters, we assumed the IBM PC keyboard would be spectacular, but it wasn’t. The PC Jr was even worse! Atari experimented with flat keyboards to save costs, and many computers had keys more reminiscent of calculator keys than you would imagine. The market voted. In general, a keyboard that wasn’t really a keyboard was the kiss of death for a computer. Case in point: the Commodore PET with its infamous chicklet keyboard, which gets a detailed examination in a recent post from [Norbert Landsteiner].
The PET keyboard gets some bad rap due to software limitations. Because of this, some games would use their own scan routines, and [Norbert] has worked on emulation able to accommodate software that wants to read the hardware directly. The resulting insights into the old keyboard is very interesting. For example, you can press more than one key at once. The result? The answer to that question takes up about half the post.
A few notable examples include a C64 emulator, minesweeper, and even a js port of Wolfenstein 3D so this isn’t just a toy, but actually useful. Ok, for real use cases, there are also the usual file browsers, and document readers as well as a writing application based on CKeditor. There is a kind of Windows 3.1 look and feel simplicity to the experience which is refreshing in the modern era of complex applications with their learning curves. Orb could be very useful in an educational setting, or just for jotting your own notes as you travel. Who knows, because the possibilities are endless if you’re willing to get your hands dirty with a bit of coding.
[jgpeiro] is no slouch when it comes to building small, affordable oscilloscopes out of common microcontrollers. His most recent, based on an RP2040 with two channels that ran at 100 MSps, put it on the order of plenty of commercially-available oscilloscopes at this sample rate but at a fraction of the price. He wanted to improve on the design though, making a smaller unit with a greatly reduced bill-of-materials and with a more streamlined design, so he came up with this STM32-based oscilloscope.
The goal of this project was to base as many of the functions around the built-in capabilities of the STM32 as possible, so in addition to the four input channels and two output channels running at 1 MHz, the microcontroller also drives a TFT display which has been limited to 20 frames per second to save processor power for other tasks. The microcontroller also has a number of built-in operational amplifiers which are used as programmable gain amplifiers, further reducing the amount of support circuitry needed on the PCB while at the same time greatly improving the scope’s capabilities.
In fact, the only parts of consequence outside of the STM32, the power supply, and the screen are the inclusion of two operational amplifiers included to protect the input channels from overvoltage events. It’s an impressive build in a small form factor, and we’d say the design goal of keeping the parts count low has been met as well. If you do need something a little faster though, his RP2040-based oscilloscope is definitely worth checking out.
Polish YouTuber WorkshopFromScratch finally got fed up with tripping over piles of garden detritus and decided to have a go at building a woodchipper (Video, embedded below). Since they had a ‘small’ 1.5kW gearmotor just lying idle (as you do) it was an obvious fit for a machine that needs torque rather than supersonic speed. The video is a fabulous 20-minute journey through the workshop showing just about every conceivable metalworking tool being used at some point.
One interesting point is the bottom roller, which sits between a pair of removable guides, which should help the thing self-feed without jamming. Whether that was necessary is not for us to judge, but it can’t hurt. The frame looks like it was constructed from at least 1/4″ thick steel, which is expensive if you don’t happen to have a supply to hand. There’s lots to see, everything from thin sheet metalworking, which was plasma cut, constructing the feed and exhaust guides, to box sections being skilfully welded at some interesting angles to make a cart to move the thing. They tell us the blades were constructed from some seriously thick slabs of C45 grade steel, but currently are not hardened. This is planned for the future, but we suspect not something that is easily achieved in the home workshop!
Working with metals can present a lot of unique challenges even for those with a fairly well-equipped shop. Metals like aluminum and some types of steel can be cut readily with grinders and saws, but for thick materials or some hardened steels, or when more complex cuts need to be made, mechanical cutting needs to be reconsidered in favor of something electric like electrical discharge machining (EDM) or a plasma cutter. [Norbert] has been on the path of building his own EDM machine and walks us through the process of generating a spark and its effects on some test materials.
Armed with a microscope, a homemade high-voltage generator, drill bit, and a razor blade to act as the workpiece, [Norbert] begins by experimenting with electrical discharges by bringing the energized drill bit close to the razor to determine the distance needed for effective electrical machining. Eventually the voltage is turned up a bit to dive into the effects of higher voltage discharges on the workpiece. He also develops a flushing system using de-ionized water, and then finally a system to automate the discharges and the movement of the tool.
What if I told you that you might never need to draw a new footprint again? Such is my friend’s impression of the tool that she’s shown me and I’m about to show you in turn, having used this tool for a few projects, I can’t really disagree!
We all know of the JLCPCB/LCSC/EasyEDA trio, and their integration makes a lot of sense. You’re expected to design your boards in EasyEDA, order the components on LCSC, and get the boards made by JLCPCB. It’s meant to be a one-stop shop, and as you might expect, there’s tight integration between all three. If there wasn’t, you’d be tempted to step outside of the ecosystem, after all.
But like many in this community, I use KiCad, and I don’t expect to move to a different PCB design suite — especially not a cloud one. Still, I enjoy using the JLCPCB and LCSC combination in the hobby PCB market as it stands now, and despite my KiCad affinity, it appears that EasyEDA can help me after all!
Ever seen a restaurant where they display fake models of the food on the menu? We never thought much about how shokuhin sampuru — the Japanese name — were made until we watched [Process X]’s video showing a 71-year-old artist creating food models. We aren’t sure what we — or you — would do with this information, but it is a striking process, and there must be something you could do with it. We suggest turning on the English captions, but you’d probably enjoy watching the unusual craftsmanship even with no words.
In years past, the food models were primarily made from wax, but since the 1980s, it is more common to use polyvinyl chloride, silicone, and resin. While some factories produce items, sometimes with a mold, single craftsmen like the one in the video still make up the largest part of the market.
We aren’t sure, but we think the material in the video is wax. We couldn’t help but think that some of this could have been 3D printed, but even with the finest resins and resolution, it probably wouldn’t be quite as artistic. We think wax is mainly underutilized in today’s tech. But there are some places it still shows up.