So far this has only been a page for a prototyping board with nothing about actual prototypes. This isn't necessarily a bad thing, but there's no harm in some inspiration for possible uses for the board.That's why I decided to add a small weekend project here: A simple controller for a Hakko-907-style soldering iron (because Chinese fakes of these and the appropriate tips are widely and cheaply available).
For this application, the STM32F030F4P6 has the perfect size with just the right number of pins and absolutely sufficient capabilities. The leshy has just enough prototyping area for the display and the few extra components the controller needs. To be fair, the encoder and jack for the soldering iron wouldn't fit on the PCB, but those look well in their panel-mount configuration here.
Being built over the last weekend, it of course isn't perfect, but I think it has some reusable components for accelerating development. Well, apart as being useful as a soldering iron for me. Code, schematic and documentation are on GitHub.