Hello,
I’ve bought some piezo vibration sensors like this one:
http://www.sparkfun.com/commerce/produc … ts_id=9198
They’re said to give up to +/-90V when the film moves…
But, I can’t get the sensor to ouput any voltage above 1V~… :shock:
What’s the trick ?
How must I wire them to get this kind of sensitivity ?
I’ve tried mesuring directly at their pin, then I put some resistors (tried 1M, 70M…) between the pins as said in the technical docs, but it doesn’t change anything… :x
I’d be grateful if someone could help me… Thanks !
Regards.
Nicolas.
What did you measure the output with? They need to feed into a very impedance; I’d use a scope.
Leon
Well I tried with my scope and with a common voltmeter… same results.
The technical manual discusses how to use a scope with them.
Leon
If I undestand well, then I have to use some kind of impedance adapter circuit before trying to measure the voltage without interfering with the piezo film.
I have some 74HCT374 Flip Flop CMOS and I see in the technical manual that CMOS are a good choice to interface piezo…
I don’t know what resistors values I should put in parallel and in series with the film, I guess I should try high values, hoping this won’t destroy my gates…
Thanks.
Nicolas.
They won’t be any use as they are TTL input. I’d use a JFET or MOSFET buffer circuit.
Leon