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

[Olav Martin Kvern]

Ingo asked: "Can you tell us more about this? Is this a harp-type MIDI 
controller,  i.e. something that outputs MIDI data when strings are pulled? 
Or does it actually make sound?"

It's a player, not a controller. It actually makes sound. I would like there 
to be some human interaction--I think things that simply play MIDI files are 
kind of boring. So we might build a separate controller for doing Euclidean 
rhythm MIDI output, or have a human use a slide on the strings or mute the 
strings.

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.)

We'll be creating a blog to show his progress at some point; I'll post a 
link on this list. He's running a bit short on time for everything he wants 
to do (hey, he's a teenager!), so he'll have to make some design decisions 
this weekend. Part of the point of the project is that I teach him about 
things, and provide a workshop and tools, but he does most of the design and 
construction work.

Hope this isn't going too far OT!

Thanks,

Ole