Many years ago a single key broke on one of my keyboards, and Yamaha just sent an entire replacement key bed. It’s got 88 weighted hammer action keys, remarkably realistic for a digital piano (though still lacking most of the complex mechanism chain that constitutes a grand piano action). It’s been sitting in my closet for a while, but I’d like to put it to use controlling some homegrown instrument.
It includes electronics for detecting when keys are pressed, and with what velocity. Interestingly, it appears to use some custom silicon! I found some documentation for the YMZ702-D chip on an Arduino forum. If this is correct, it pumps out note data in a simple binary format using an SPI interface.
Note: This project did not go anywhere. I guess the keys will stay in my closet at least another season.