Laser harp

[Bert Schiettecatte]

Sorry if I ask a stupid question, I'm just new to this diy-stuff ...

I've been thinking with a friend to build a laserharp, a bit lile JM. Jarre. Does anyone have an idea 
how to make this harp velocity-sensitive ?

What would be intresting values to assign to beams, and in what way should the beams be arranged,
if I want to use this device with a Korg Wavestation to develop new sounds ?
(i have the complete sysex table, since I own a wavestation original ...)

Bert.