Here is the idea (pic. 1). Let the line sensor represent one piano key. Place several white and black areas on a sheet of paper. Then, move this sheet relative to the stationary line sensor.

This module allows the user to wire up an Arduino to any conductive interface (fruits, cans, ect.) and play sounds using that interface. It can be used to create sounds in an integrated system or ...

Posted in Arduino Hacks Tagged arduino, capsense, keyboard, piano, synthesizer, touch sensitive, touch sensor ← The Thinnest Xbox Laptop Yet Keurig Hack Now Automatically Fills The Water ...

The sensor forms an image and OpenCV detects the actual touch configuration. It appears you can use the raw data from the Arduino, too, but it might be a little harder.