MIDI controller for 49 piezo transductors with velocity?

[lastshaman]

Hi all,

I'm building a prototype of an innovative MIDI instrument which will work like a giant drumkit with 49 pieces.

Is there a DIY MIDI controller capable of 49 inputs from piezo trasductors with velocity information?

I only found projects for controllers with 8 inputs.

Thanks in advance for your help

Roberto

[guiseppi]

The only project I know of that is close to that is the eDrum, which is an 8 channel velocity sensitive drum.

With a little work, the analogue portion of the circuit could be expanded for many piezo's, the main parts are not too expensive.

Obviously, this would also involve your own code, as well as using either a bunch of AD chips or 4x PIC with 13 AD inputs (e.g. 18F4420, I got these cheap from Rapid Electronics UK recently) and using one as a master device also.

http://www.edrum.info/schematics.html

[lastshaman]

Hmmm. I'm a programmer, so maybe I could modify the code, but I don't have any cognition about modifying the circuit. :-(

I would really appreciate some help in that field.

[Sasha]

Edrum supports 24 velocity sensitive trigger inputs not 8.  ;)

[guiseppi]

Oh. I didn't spot that ;)

In that case, a few multiplexers rather than multiple PIC's would be more sensible, but it still means modifying or rewriting code.

The analogue part of the circuit with the LM324's simply converts the pulses from the piezo's into a ~0-5v range for the PIC inputs, so could be used in any project as is for triggers. Kits can even be bought. It might be sensible to use fixed resistors at the piezo inputs or small cermet trimmers rather than so many pots. Calibration in software if needed..

[stryd_one]

IIRC eDrum is not open source, so software mods are not possible.