[sdiy] MIDI harp, was: (OT)help processing realtime audio on Arduino?

[Ingo Debus]

Am 02.02.2011 um 19:24 schrieb Olav Martin Kvern:

> We'll have a microcontroller take MIDI messages and strike/mute  
> strings--we're still messing with the mechanism. My guess is that  
> it'll use solenoid strikers and mute using small stepper motors,  
> but there's a good argument for using a stepper to pick (rather  
> than strike) each string. A kind of clavichord arrangement is also  
> possible.
>
> Each string will have a pickup, which will lead to a preamp/VCA in  
> a MIDI controlled mixer. We'll handle MIDI velocity at the VCA,  
> rather than trying to control the striking/picking mechanism. He'll  
> be winding all of the pickups--and the solenoids, if we decide to  
> go that route. (We may use a dozen of Tom Wiltshire's excellent PIC  
> ADSRs to provide envelopes.)

Whoa, that's an amazing project for sure! Are you using a ready-made  
harp, or is this part DIY also? It's certainly not easy to handle the  
added forces of all the strings if they all are mounted to a common  
frame.

I'd be wary of the solenoids and stepper motors. Don't they make more  
noise than the strings themselves? But if you're only interested in  
the electrical output of the pickups, it probably doesn't matter. But  
if you have ADSRs, why mute the strings mechanically?

I think, controlling the intensity of the mechanical strikes is very  
different from electronic volume control. Is it so difficult to  
control the solenoids' currents?

Just a few random thoughts. I'll sure read your blog once it's up.

Ingo