On the electronics and interfacing side of things, [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 ...

A low-power, compact keypad module based on the STM32L010K4T6 microcontroller. This project includes a 12-button keypad interfaced with a host MCU via I2C or UART, designed to serve as a mini keyboard ...