key64tapper emulates the keyboard of Commodore 64. It allows one to send a string of characters, or interactively type in characters, from a PC/Mac/Linux computer, and have it displayed on the C64 screen.
The project is just another take on microcontroller + crosspoint switch + keyboard combination. When I built it, I was convinced nobody had had that idea before, but when I announced it I was made aware that I was not the first! Similar project are listed in the Reference Material section.