For those into home-brew programming projects, its easy to make a microcontroller spit out some Morse code with the post shown below. What makes [pavlin’s] take on this project interesting is that it resides on a tiny USB board with an ARM processor. The design for the board is available with single-sided artwork suitable for production using simple methods like toner transfer.
The STM device has a built-in USB bootloader. It can also act as a serial port, which makes the project very simple and a bit more flexible. The only external parts are a speaker and an opt-oisolator.
The program provides a command line interface over the serial port that you can use to program the message and set other options like speed and the delay between messages.
The code is available on GitHub.
