[Andres] wrote in to share his USB for NES controller project (translated). It enumerates as a USB keyboard and is easily mapped on most emulators. Over the weekend we looked in on an AVR ...

So [Andrew] went a step further and made his own SNES controller to USB converter. This had the venerable Atmel ATmega328 at its core, and can be used separate from the cartridge reader if desired.