With the C64 JoyKEY I wanted to build a simple joystick, but given how well it worked I wanted it to work with more than a handful of systems. You could certainly use it directly as a three-button joystick for the Commodore 64, but this module is however not about the Commodore 64 - it's all about making it work on the Nintendo Entertainment System (NES) instead! Meaning that if you have a C64 JoyKEY then you can use it as a regular controller on your NES, by pairing it with the C64 JoyKEY arcade you can easily use it as a basis for building your own NES-controller using arcade parts.

NB! This design isn't associated with Nintendo in any way, I just built it in order to easily play games on their original 8-bit console. If it wasn't already clear, this is only an adapter for the system and not the joystick itself - for the main PCB as well as other adapters you might be interested in, check out my other shared projects relating to this project. For BOM and build instructions, have a look at my github-repository.