If you have a non-functional Commodore 64 collecting dust in a closet somewhere, this hack by “EricHOlsen” shows you how to convert it into a Bluetooth keyboard, complete with a LiPo power supply and charging circuit. It’s been tested on iOS devices, and should work on other systems, though this is left as a “reader exercise” so to speak.
The heart of the modified contraption is an Adafruit Feather M0 Bluefruit, which as the name implies allows it to send commands via Bluetooth. It also includes a LiPo charging circuit to help with power requirements. Input capabilities are augmented by the use of a 74HC595 shift register, and a second shift register chip takes care of controlling a tri-color LED for feedback.
The project’s electronics were first hooked up on a breadboard, then transferred to a more permanent perfboard setup once everything was verified to work correctly (a step that’s always tempting to skip when immersed in a build). The C64 body gives a good amount of room to hide the new electronics when stripped of its motherboard, helped along here by a 3D-printed mount, and a copious amount of hot glue. While an interesting hack, one might also feel a little sorry for the ancient computer, sentiments echoed in the hack’s comment section if you feel like reading or chiming in.