[John] utilises the Arduino pro micro for its copious analog inputs and USB functionality. A nice feature of this board is that it’s based on the ATMega32U4, which can quickly implement USB ...

Rather than be left on the wrong side of the divide [Stefan S] has come up with his own USB-C version of of an Arduino Pro Micro to avoid ... much slower speed of the ATMEGA32U4 processor, but ...

It's like a shrunken version of the Arduino Leonardo as it features the same ATmega32U4 microcontroller, micro-USB port, and pinouts. It also operates at 5V and requires an external supply of 7 to ...