multiple piezos triggering 1v/Oct CV voltage

[Mbira]

Hi guys,
It's been a while!   And while it has been a long time since I have posted here, my electronics abilities have not improved at all! In fact they have probably gotten worse.  In any case, I have been totally bitten by the modular synth bug, and I'm having a blast!

I have the marimbas that I build for the band, and in each key there is a piezo trigger that I have been sending through an audio to MIDI converter.  Now, I want to totally ditch the midi and computer.  I want to go out of a DB-25 from the marimba.  The DB-25 has 19 individual piezo triggers.

I want to then plug that DB-25 into a module that will take each individual signal and let me assign a specific voltage for when that trigger is struck. 

I understand that probably the easiest way to do this would be with some sort of logic and programming, but I really want to create this circuit with purely analog circuitry-if only to help myself learning. 

I was looking at a 555 timing circuit: http://www.electroschematics.com/10166/piezo-trigger-switch/ 

From what I can tell, this circuit will take a trigger from  a strike on the piezo and then hold a gate signal high for a time that is determined by the r/c network.  That seems easy enough and that I could dial in that network to reduce false triggering or debouncing.

So I'm thinking having that circuit with a trim pot to adjust that r/c network.  That will take care of the trigger.

Then I need that to feed into a circuit that will detect the trigger and when it is high, it will output a specific voltage.  These modular synths work from 0-10V and there is a 1 v per octave range.  I work in non-western tunings, so I would like to have a trim resistor that will let me fine tune each specific pitch to the exact frequency that I want...I don't know how this circuit would look, but I'm thinking this is just a basic transistor sort of circuit?

Then the third part of this circuit would listen to all of the incoming voltages and output only the most recent voltage.  This is a part of the circuit that I don't know what I'm looking for at all. 

Can anyone point me in the right direction-or at least tell me if I'm moving in the right direction?  Thanks so much!

 

[gyraf]

You should probably look into an envelope follower with additional trigger output - and then simply attenuate the trigger output level to a suitable control voltage.

The beauty of envelope follower would be that you will get original dynamics information in CV format, which tends to make playing much more intuitive than fixed-time-triggering (for driving VCA's and VCF's)...

Jakob E.

 

[Mbira]

At this point, I'm not trying to add the complexity of velocity sensitivity.  I can handle that with a foot controller while I'm playing.  I'm really hoping for the simplest circuit (to start with) just so I can actually achieve it and hopefully even understand what I'm trying to do!

I hope that I'm understanding what you mean about an envelope follower? 

Since each marimba has 19 triggers, I would want to treat each as a monophonic instrument and sending 1v/oct and gate output for each monophonic instrument. 

 

[Mbira]

Any other thoughts on this?