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From: lansd@utgpu.UUCP
Newsgroups: rec.music.synth,sci.electronics
Subject: Simmons drum pads
Message-ID: <1987Mar25.021417.3679@gpu.utcs.toronto.edu>
Date: Wed, 25-Mar-87 02:14:17 EST
Article-I.D.: gpu.1987Mar25.021417.3679
Posted: Wed Mar 25 02:14:17 1987
Date-Received: Thu, 26-Mar-87 00:35:59 EST
Organization: University of Toronto Computing Services
Lines: 18
Keywords: simmons
Xref: utgpu rec.music.synth:476 sci.electronics:402
Checksum: 31102


   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)?