[sci.electronics] Simmons drum pads

lansd@utgpu.UUCP (03/25/87)

   Is anyone familiar with the velocity sensing mechanism used
in the Simmons Drum Pads? About a year ago I constructed a drum
pad system using Piezo-Electric crystals, some level detection
circuitry and a Z80-Pio to latch the level changes as interrupts.
   Well, now I would like to make the system velocity sensitive,
but see major problems. A little bit of research a year ago showed
that the cystals have a fairly constant voltage output verse how
hard you hit the pad, so I really can't use these pickups for
measuring the hit velocity.
   I thought the SDS-4 (way back when) used a carbon microphone in
the pads, so the velocity info should have been easily removed from
the dynamic response of the mike. Do they use a capacitve foam in
the latest SDS pads?
    What I would really like to find out about the SDS system is:
	- what kind of pickup mechanisms do the pads use?
	- how do they convert the pad outputs to a velocity value
	  (in explicit terms if possible)?