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Does anybody know how to make a surface transducer? Answered


I want to build some surface transducers. Any suggestions?

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icengBest Answer (author)2011-10-20

The easy surface transducer, I like to use is a pair of magnets holding a 
piezoelectric disc to a metal surface ( see first & second pic ) and feed
that to an opamp.

Try making a strain gauge.  Glue a very fine ( 50 gauge wire ) zig zag
across the surface you want to monitor ( see third pic ) and you can measure the wire resistance changes as the surface is stressed.

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user
blinkyblinky (author)iceng2011-10-20

Thanks.

What is the output volume?

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iceng (author)blinkyblinky2011-10-20

Piezoelectric disc are real Loud and strain gauges are like a fly talking.

A piezo can run a uP analog input or two differential pins directly and
you still need to protect the uP with series resistors and diodes to Vcc
and from ground.  BTW a simple piece of paper insulates the disc from
the metal surface.

The strain gauge change is in millivolts.  You will need an OpAmp to
amplify the signal before it can be useful.

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blinkyblinky (author)iceng2011-10-20

"...you still need to protect the uP with series resistors and diodes to Vcc
and from ground. BTW a simple piece of paper insulates the disc from
the metal surface."

I'm not sure what you mean.

What does BTW mean?

Thanks again.

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iceng (author)blinkyblinky2011-10-20

Attached a PDF of how you interface a piezoelectric crystal to uP.

By the Way I had to look up the google Common internet catch anagram meaning
of BTW when I was curious as you must ( No Spoon feeding here )

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iceng (author)caarntedd2011-10-21

Thanks, as far as I know this AFAIK was my most recent perplexing anagram,
also had to look it up.

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iceng (author)caarntedd2011-10-21

Ha ha... slip of the tongue :-)
The word speller works good, but doesn't fix word choice.
Could have been a Freudian slip, It was a puzzle to me.
Thanks for catching it.

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thes007 (author)iceng2011-10-27

Initialism actually. Acronyms spell or create words (i.e.. NATO, UNICEF, SHIELD (Supreme Headquarters, International Espionage, Law-Enforcement Division)). Initialisms are just initials (FBI, CIA, NBC, LMFAO). Just thought I'd help straighten things out a bit.

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blinkyblinky (author)thes0072011-10-27

I did not post the reply to start an acronym revolution!

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