Using sound to create electric pulse

Thread Starter

rwijupal

Joined Dec 5, 2016
5
Hi,
I am trying to create small mv electric pulses using sound, ideally ultrasound. i had used ceramic piezoelectric plates (25mm, 4.6khhz rezonance freq) for the same. can someone suggest what type of piezoelectric material i should use or some good study material for the same.
 

Thread Starter

rwijupal

Joined Dec 5, 2016
5
Why not use a cheapo electret microphone capsule? They're alleged to work up to ultrasonic frequencies.
Hi Alec,
Actually I thought a a piezoelectric plates would be cheaper than getting a mic capsule. hence chose that. I need at least 10,000 of either the mic or piezoelectric capsule. considering my requirement do you still suggest to move to a mic
 

Alec_t

Joined Sep 17, 2013
11,526
You haven't stated what frequency you need to detect. 4.6kHz is nowhere near ultrasonic, so the piezo plate you mentioned may not suit.
 

Thread Starter

rwijupal

Joined Dec 5, 2016
5
This is marginally "ultrasound" because some people can hear 20 KHz. Is it possible to go above 20 KHz? By mobile, can I assume that you mean a cell phone?
Hi RichardO,
Ya i know its marginally ultrasound but i can only get a mobile (cell phone) to generate sound of max 20khz.
 

WBahn

Joined Mar 31, 2012
26,068
It might help to start with the problem you are trying to solve so that people can offer suggestions relevant to the problem instead of asking about part of a solution to an unknown problem and making people guess about what information might or might not be relevant to the problem.
 

Thread Starter

rwijupal

Joined Dec 5, 2016
5
Sure. I am tryjng to generate enough electricity using sound to light two leds to start with. i want to use the frequency range of a mobile cell phone for the same. I had initially started working with piezoelectric as cost is a major concern for me, considering the large number of convertors i would require
 

WBahn

Joined Mar 31, 2012
26,068
Sure. I am tryjng to generate enough electricity using sound to light two leds to start with. i want to use the frequency range of a mobile cell phone for the same. I had initially started working with piezoelectric as cost is a major concern for me, considering the large number of convertors i would require
Have you taken any look at all at the power budget?

How much energy do the two LEDs need to be lit?

How much sound energy does the cell-phone speaker emit?

What fraction of the sound energy emitted by the cell-phone speaker makes it to your transducer?

What is a reasonable upper limit on the conversion efficiency of the transducer from sound to electrical energy?

Is the product of the last three numbers even in the ballpark of the first?
 

Alec_t

Joined Sep 17, 2013
11,526
Why do you need at least 10000 of these sensors? If they are any significant distance from the cell-phone their signal pickup will be extremely feeble. Certainly not enough to light a LED.
 
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