Goal of this project:
Convert a cheap toy piano to work as a midi device and use it with Synthesia (http://www.synthesiagame.com/
Other programs that use midi inputs can also be used.
The pushbuttons of the piano are used to make a simple pull-down circuit for the arduino mega. The arduino interprets the keystrokes and sends serial midi data to the pc. Then this data is send to a virtual midi port with "serial-midi converter". This midi port is connected to Synthesia via "MIDI Yoke". MIDI Yoke is a driver that creates virtual ports. Each port has an input and an output which are connected. With MIDI Yoke you can couple different midi programs without any physical hardware.