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DIY $3 contact microphone/piezo pickup


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Hello all,

 

I hacked together a piezo pickup for acoustic instruments (initially to test the sensitivity of the piezo elements I'm going to use in another project, but this experiment turned out rather well). This thing is awesome. My roommate and I had fun with this thing for hours last night, taping it to everything... even our throats. It picks up voices!

 

Anyways, the whole thing can be built for around $3 from RadioShack, assuming you already have a soldering iron, solder, and electrical tape. But who doesn't?

 

I did a write up with pictures and demo recording on my blog. Check it out here: http://blog.suspended-chord.info/?c=25

 

:D

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very cool! now thats great pratical physics demostrated. i wonder if it can be made into a bike intercomm, that would be a great application as wind noise would cut out normal intercomm usage.

 

i wish we still have radioshack in canada (they got brought and now became "the source"), looking at all the great deals mentioned here.

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Cool. Just hooks to any amplifier?

Yes, or mixer, or pre-amp, or... anything which takes a mono audio signal.

 

i wonder if it can be made into a bike intercomm, that would be a great application as wind noise would cut out normal intercomm usage.

It might. I suggest you try it and see! One thing to notice though, it works on vibration, not air pressure. You can blow on it, but if you just talk at it it won't pick up anything. However, as mentioned in my blog post, it works great (though a bit bass-heavy) if taped to someone's throat.

 

Thanks for the comments!

 

EDIT: hit submit too early.

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Great work! I tried a similar thing in the past, but I was more interesting in using the piezos as pressure sensors instead of picking up sound (well, technically with sound it also sense the wave pressure...). I attend a bioengineering congress in wich some guys show how they hook up a bunch of these on an insole (i'm not sure if i'm using the right term here) in order to measure the foot preasure for gait analisys. It is a cheaper solution compared with comercial ones.

At the end i had some problems with the signal, those things work great with sound but don't have a good behaviour with constant preassure, and I eventually quit it... :roll:

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...those things work great with sound but don't have a good behaviour with constant preassure, and I eventually quit it... :roll:

Don't they only generate signal with pressure changes? I guess you could have assumed that no signal meant no change in pressure since last reading (as long as you were reading frequently). I'm probably wrong, though; I've never used peizos. :?

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Don't they only generate signal with pressure changes?

yes indeed. i found that later...after destroying one :oops: assuming that more pressure was better :lol:

after seeing the paper about the proyect i was talking about I realised that the way to do it was with a capacitor to store the voltage that the piezo generates, take a sample and discharge it. Perhaps in the future if I can get some piezos i'll try it out again

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Well, one goal of this was to see if I could make them work as pressure sensors (well documented, I know, but I'm a hands-on kind of guy), but they're going to be activated in single concrete events, not in a continuous fashion.

 

I'll need some resistors when I use them in that capacity, but they will work, as this has demonstrated.

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