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Stretch

Posted: Tue Mar 08, 2016 4:08 pm
by chputney
I am trying to use the stretch sensor without a digitizer as an ADC input to a processor for a breathing monitor. I find that the resistance of the rubber element at rest is about 8K. When the rubber is stretched this resistance can decrease, somewhat but when the rubber is released, the resistance climbs to about 10K and then gradually drops back to 8K over a period of tens of seconds.

When the rubber is stretched and released cyclically at about 1 cps, the resistance is about 8K when stretched and 10K when released.

It is not possible to correlate the resistance with pulling force (as the web page suggests) because of this material's long time constant.

Any clues how I can get over these difficulties to measure breathing ?