Kritik sah

Multitasking is something we take for granted these days. Just about every computer we use, from our desktops to our phones, is capable of multitasking. It might sound silly to implement multitasking on lower-spec machines from many decades ago, given their limited resources, but it can be done, as [bchiha] demonstrates on a Z80-based machine. [bchiha] has achieved pre-emptive multitasking on the TEC-1G Z80 computer, a modern reimagining of the classic Talking Electronics TEC-1 from the 1980s.  The proof of concept code allows running up to eight separate tasks at once. Task switching runs on interrupts, triggered at approximately 50 Hz. When an interrupt fires, the CPU registers are transferred onto that task’s stack, and the next task’s stack is swapped to the stack pointer to allow execution of the new task to proceed. There is an overhead, of course, with [bchiha] noting that the task swapping routine itself takes about 430 clock cycles to run in between tasks. Multitasking...

If you’ve ever wanted to pump sound to all the rooms of your house, you might use any one of a number of commercial solutions. Or, you could go the more DIY route and whip up something like the Esparagus Audio Brick built by [Andriy].  The concept is simple—it’s a small unit, roughly the size of a brick, which streams high-quality audio. It’s based around an ESP32, which pulls in digital audio over Wi-Fi or Ethernet. The microcontroller is hooked up to a TAS5825M DAC, which comes with a built-in amplifier for convenience. The Esparagus is designed for integration with Home Assistant, allowing for easy control as part of a smart home setup. It’s also compatible with Spotify Connect, AirPlay, and Snapcast—the latter of which provides excellent sync when using multiple units across several rooms. Design files are available on Github for the curious. We’ve seen other neat projects in this space, before, too— like the charmingly-named OtterCast . Video after the break. from Blo...

The solar-powered quadcopter from below. (Credit: Luke Maximo Bell) One of the most frustrating parts about flying a quadcopter is having to regularly swap battery packs, as this massively limits what you can do with said quadcopter, never mind its effective range. Obviously, having the sun power said quadcopter during a nice sunny day would be a much better experience, but how workable is this really? While airplanes have used solar power to stay aloft practically indefinitely, a quadcopter needs significantly more power, so is it even possible? Recently, [Luke Maximo Bell] set out to give it a whirl . His quadcopter build uses a large but very lightweight carbon fiber frame, with large 18″ propellers. This provides the required space and lift for the solar panel array, which uses 27 razor-thin panels in a 9×3 grid configuration supported by a lightweight support frame. Due to the lightweight construction, the resulting quadcopter actually managed to fly using just the direct po...

For our 2025 Component Abuse Challenge there have been a set of entries which merely use a component for a purpose it wasn’t quite intended, and another which push misuse of a part into definite abuse territory, which damages or fundamentally changes it. [Ken Yap]’s use of a transistor base-emitter junction as a voltage reference certainly fits into the latter category. If you forward bias  a base-emitter junction, it will behave as a diode, which could be used as a roughly 0.7 volt reference. But this project is far more fun than that, because it runs the junctions in reverse biased breakdown mode. Using one of those cheap grab bags of transistor seconds, he finds that devices of the same type maintain the same voltage, which for the NPN devices he has works out at 9.5 volts and the PNP at 6.5. We’re told it damages their operation as transistors, but with a grab bag, that’s not quite the issue. We’ve got a few days left before the end of the contest , and we’re sure you can t...