[sdiy] Piezo keyboard

[Peter Grenader]

All,

I was poking around looking for some parts yesterday and came upon ten
sample piezo switches from a place called PIEZO Development I had and forgot
all about (goto http://www.piezoswitch.com/about_switches.html).  The ones I
have are really slick - they don't have a ridge around the perimeter like
the ones in the photograph on their site -- they're basically these flat
polished clear anodized aluminum disks, about the diameter and height of a
quarter and not only pass a signal that's put through them, they do so with
pressure sensitivity.

These are designed for underwater use.

So I've got some faceplate space coming up and I thought I'd do something
with these.  I've laid out a ten position keyboard, which is also going to
house my Smokin' Joe (joystick) and so far I've included:

a tunable voltage level per key and an output for that
a pressure sensitive output per key
and a trigger/gate output per key (switch selectable between the two).

As far as the ganged outputs, I was thinking of a MSB output of:

the tuned voltages 
an output of linear preset voltages (each key increments  X volts)
a ganged pressure out (with sensitivity pot)
a lag output (with glide time pot)
a gate out 
a separate trigger out (with pulse eidth pot).

Anything else I should consider while I'm at this critical 'put it on the
faceplate or you're screwed' stage?

My only complaint is it takes a bit more pressure than I would like before
they short, but these things are so cool and I can forgive this.  But I
won't be able to simple run my hand across and get a reaction like I would
with touch keyboard.  Possibly however in time I could use these just as
contact plates and not incorporate their internal switch at all - there's a
possibility this will work.  But if not, I'm OK with it.

So, any feature creep you guys can think of?

- P