[sdiy] touchplate keyboard - works!

[Roy J. Tellason]

On Saturday 05 February 2005 02:05 pm, Ian Fritz wrote:

> I'm missing something. Could you clarify how you get a pressure output? It
> seems to me the piezos just put out a pulse. In fact, it's impossible to
> get a dc voltage from a piezoelectric transducer, since they are
> capacitive.

Eh?  A piezoelectric material is defined as one where,  when you apply a 
mechanical force you get a voltage,  and vice versa.  Same principle that's 
used in crystal-controlled oscillators,  too.

They may be "capacitive" in the electronic sense,  but that doesn't change the 
principle of operation...