This is a collection of easy to build adapters for connecting SNES, NES, Mega Drive/Genesis (3/6-button), Master System, Atari, Commodore, Amiga (incl. CD32) controllers to USB. Support for more controllers is on the way (Sega Saturn, NeoGeo etc.).
You will need the [Arduino IDE](https://www.arduino.cc/en/Main/Software) to build the projects. Download the whole repository via the "Clone or download" button, open the project you want to build in the IDE and select "Arduino Leonardo" in Tools / Board. Connect the Arduino to a USB port and build/upload from Scetch / Upload.
The Mega Drive gamepad interface is based on this repository : https://github.com/jonthysell/SegaController but almost entirely rewritten and a lot of optimisations have been made.