Solenoids in the piano are connected to its keys through aluminium extrusions, allowing the system to play songs by activating solenoids in the correct sequence and with the right power.
Using ten solenoids to mimic the actions of ten human fingers could have been simpler and cheaper, but the current design allows the piano to play songs that would be impossible for a human to perform.
The current design also means there is a noticeable click when the solenoids activate, but this issue can be solved by attaching orthodontic rubber bands to the solenoids.
References are provided to other musical instrument automation projects, including a xylophone-playing device and a player piano using a 555 chip.
