KiCAD library and footprint for an Arduino Micro shield. This is a component which represent the Arduino Micro pinout, and a footprint for that component which maps to the surface area and pinout of ...

Microduino: An Arduino clone nearly as small as a quarter, for $20 Arduino Uno capabilities divided into two small boards for extreme portability.

An Arduino Nano or a Micro might be the best options If a small board sounds like the most appropriate choice.

$6 Maker UNO Arduino UNO Clone Comes with Micro USB Power, I/O LEDs, and a Buzzer Arduino UNO is one of the older Arduino boards, but also one of the most popular, and there are already many clones, ...