So came up with a new use for my portable drawing machine: the scariest player piano ever.
The machine runs LinuxCNC on a Beaglebone Black, has a custom kinematics engine. In this application I laser cut strikers for the kids piano so that I could hit the keys sideways rather than vertical, made a quick map of the XY coordinates for each key and then wrote a script in Processing to pass G-code to the machine over a serial link.

Tada, wrecking ball player piano