a little project I showed at superbooth
I really like bela (http://bela.io) for this kind of thing since it outputs 0..5v, so basically all I did for this was to create a small board that interfaced the right pins of the bela, onto a ribbon cable connector, then a small ae module with a ribbon connector to expose the pins to ae - simple and effective.
bela is too big to put in the rack, so need a 'tidy' way to have it connected.
( of course, I also had to write the software to talk to the eigenharp pico , which took a while )