General operation
The laser harp we want to design consists of a number of beams each
corresping to one note, or of a cluster of beams corresponding each to one
note. Most laser harps currently existing use only one beam for note
on/note off, and use some other sensor to determinte note velocity.
By using multiple beams per string, it is possible to have both note
velocity (e.g. how many beams are interrupted) and attack time (e.g. how
much time is between the interruption of the beams).
A foot pedal can be added for extra expression control (e.g. modulation
depth), as well as a distance sensor per beam cluster (e.g. used for pitch
bend).