Cheap toy pianos don’t usually have MIDI, and getting a velocity-sensitive keyboard from something out of the toy aisle at Walmart is nearly out of the question. If you’re willing to tear one of these toy pianos apart and build your own control electronics, though, the sky is the limit, as [JenShen] shows us with his home built velocity sensitive keyboard.
Usually, velocity-sensitive keyboards have two buttons underneath each key. By having a microcontroller measure the time difference between when each button is pressed, it’s possible to sense how fast each key was pressed. [JenShen] took the idea of a velocity-sensitive keyboard in another direction and instead used a force sensitive resistor strip, cut up into many pieces to provide velocity and aftertouch data.
[JenShen]’s keyboard adds these resistive buttons to the button matrix he already made. The result is a very inexpensive velocity sensitive keyboard with aftertouch, an impressive feat for an Arduino and only a few components.
You can check out the keyboard in action after the break.