Blue Pill Makes Cheap But Powerful Morse Tutor

[W8BH] attended a talk by another ham, [W8TEE] that showed a microcontroller sending and receiving Morse code. He decided to build his own, and documented his results in an 8 part tutorial. He’s using the Blue Pill board and the resulting device sends code with paddles, sends canned text, provides an LCD with a rotary knob menu interface, and even has an SD card for data storage.

All the code is on GitHub. If you are interested in Morse code or in learning how to write a pretty substantial application using the Blue Pill and the Arduino IDE (or any other similar processor), this is a great exposition that is also a practical tool.

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Text Projector With — You Know — Lasers

We missed [iliasam’s] laser text projector when it first appeared, perhaps because the original article was in Russian. However, he recently reposted in English and it really caught our eye. You can see a short video of it in operation, below.

The projector uses raster scanning where the beam goes over each spot in a grid pattern. The design uses one laser from a cheap laser pointer and a salvaged mirror module from an old laser printer. The laser pointer diode turned out to be a bit weak, so a DVD laser was eventually put into service. A DVD motor also provides the vertical scan which is just a slight wobble of a mirror. A Blue Pill CPU provides all the smarts. You can find the code on GitHub.

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Do Other Things Besides Output Video

Small microcontrollers and tiny systems-on-chips are getting more and more popular these days as the price comes down and the ease of programming goes up. A Raspberry Pi is relatively inexpensive and can do pretty much everything you need, but not every chip out there can do something most of us take for granted like output video. For a lot of platforms, it’s next to impossible to do while saving any processor or memory for other tasks besides the video output itself.

[Dave] aka [Mubes] has been working on the Blue Pill platform which is a STM32F103C8 board. While they don’t natively output video, it’s a feature that provides a handy tool to have for debugging in order to see what’s going on in your code. However, if the video code takes up all of the processor power and memory there’s not much point. [Dave]’s video output program, on the other hand, takes up only 1200 bytes of RAM and 24% of the processor for a 50×18 text display over VGA, leaving a lot of room left for whatever else you need the tiny board to do.

Video output on a device this small and lightweight is an impressive feat, especially while saving room for other tasks. This brings it firmly out of the realm of novelty and into the space of useful tools to keep around. If you want to try the same thing on an ATtiny, though, you might have to come up with some more impressive tricks.

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