About as bare bones as you can get for a dev board, but fits perfectly into a breadboard or perfboard project. Initially inspired by the F103C8T6 'Blue Pill' form factor, but shrunk down to use a 20 pin TSSOP package. You can either provide power from the power pins or over the USB connector, and use the SWD debug header for programming. Comes with a reset button, power and user LEDs. Full open source, feel free to make your own! (a future rev might end up on Tindie)

List of things to fix for next rev:
1. Spend however many more cents it takes to get the version with built-in USB
2. Add an external crystal option (currently doesn't have one)
3. Add an RTC package that isn't a pain to solder (currently uses a resonator)

...but it does work, so I'll get around to those later ;)
NOTE: Turns out I switched the silk on SWCLK and SWDIO, so you'll want to switch those wires when you're programming. Working on a rev 2 that fixes this