A few questions about aftertouch sensors

[maki]

1) how is an aftertouch sensor made?
2) are there different types of sensors?
3) what is the smallest type?
4) any good internet pages about the subject?
5) how are they incorporates in a key?

thanks!

[Meffy]

I'm thinking elastomeric elements might be included -- rubbery stuff impregnated with a conductive material, a hunk of which changes resistance when compressed. But that's a guess. I'd like to know what's really being used.

Good questions. If anyone knows I'll be as interested as you in learning the facts.

[jupiter8]

I'm not sure but the easiest way i can think of is simply having a piezo element under the keybed. Simple,cheap and easy to make. If that's the way it is actually done i don't know.