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minerva
03-07-2007, 11:15 AM
Hi
My project group is building a "mechanical gravity canceller" for a class project. We need to use something·to measure the changing weight diameter is larger that the diameter of the·flexiforce sensor (sensing diameter .375"). Will the weigh be accurately measured.

PS. Has anyone used the flexiforce sensor demo kit

Thanks

James Long
03-08-2007, 01:05 AM
Minerva,

If the weight is applied to the sensor correctly ( like on a washer or such) it will.....if the weight is touching(being supported) anywhere else....there will be some error. This all depends on how large the mass is you are trying to weigh.....and the shape.

I don't know if this answers your question.....but I hope this helps,

James L

steve_b
03-08-2007, 03:16 AM
I bought a few flexiforce sensors (not the demo kit) to test the pressure some conductive brushes had on their contacts.
I really didn't get repeatable results. I think part of the problem was that the surface I wanted to measure was not uniform (was curved) and you need to preload the sensor before using it.
As far as I can tell, the 'preloading' helps distribute the resistive paste in the sensor so that it's more uniform. If you don't do this right, you're readings will not be the same.

It's a pity they do vary so much, as I have a tonne of ideas for these devices.....and they can easily be measured with a DMM!

You might look at the piezo elements that produce a voltage with pressure (although DO be sure to use the interface circuit to avoid large voltage spikes that'll kill your processor).

cheers

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Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."