Replacing an Apple IIe Keyboard Controller with Arduino

After attempting to fire up his Apple IIe clone that he describes as “a bit of a turd” for the first time in 20 years, Max Breedon found that the keyboard decoder chip was burnt out. Given the computer’s age and manufacture, a replacement wasn’t available, and he wasn’t even able to find information on the chip searching the Internet.

Rather than give up, he figured out how the chip worked, and programmed an Arduino to decode keypresses from the keyboard with the help of an SN74HC595 shift register. It then sends this information serially to the computer as ASCII characters.

The setup was prototyped using an Uno, then transferred to a Nano and perf board as a permanent solution. You can find more details on the replacement decoder and the build process here.

[h/t: Hackaday]