Your MIDI keyboard should now be successfully interfaced with your computer, potentially via your audio interface. This ...

So he pulled the same trick with a USB keyboard. Along the way ... [Dastardly] makes a homemade daughterboard–er, shield–to connect it to the Arduino. The result is a nice little sandwich ...

Mice and keyboard had mechanically identical ... As we all learn and get better at it together, hopefully USB-C will actually become that one plug to connect them all.