Jaggermax

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I just received a robotic's book from Barnes and Nobel and it has some excellent info on sensors and op amps circuits.  I came across a short paragraph in the book on motion sensors and the author says he has used "Piezoelectric Film" for motion sensing of human bodies.  He also mentioned that a number of motion detection security companies use this same film in their motion sensors.  This film generate a voltage whenever a change in heat, vibration, or stress is applied to the film.  

I did some quick searching on the web last night and it seems that this sensor can detect infared heat if mounted behind a fresnel lens.  I found these sensors for sale at Digikey for only .75 cents each. The only problem with the sensor that I can see is that two would have to be used together with an Op amp differential circuit to cancel the effects of wind, sunlight, etc..   The standard RE200b PIR that a lot of us are familiar with has this circuitry built in.  Any of you guys (Arc, Richard...) ever used this stuff before?  Just curious.  I found a company that makes the film and they have some neat info on what it can do.  http://www.msiusa.com/piezo/index.htm
 

Archilochus

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Hi Jaggermax,
I actually have a few of the MSI parts - Digi-Key part#MSP1007-ND "LDT vibration sensors" in my "stuff" box.  I've been fooling around with a "seismic" trigger for my cams.  I've never heard of these parts being used for motion sensors, but I'll check them out and see if they work at all.  Even if it can sense motion, seems like a big problem would be vibration or even microphonic noise setting the thing off.  Don't know if there would be a way to tell the difference between a vibration signal and a motion signal.

Archilochus
 
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