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Basic Electronics » Using Piezzo Buzzer to produce Ultrasound?

October 17, 2009
by srjcstud
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Is it possible to produce ultrasonic sound waves using the Piezzo Buzzer? The crystal in our kit is approx 14 MHz and according to wikipedia the frequency of ultrasound is above 20 KHz. If it is possible, then is it also possible to send out and read ultrasound waves. This could be used to make an ultrasonic range detector. I have a very limited knowledge of this sort of stuff, so I appreciate any input.

October 19, 2009
by rusirius
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well since nobody else has answered, I'll take a stab at this one.

Yes, it certainly should be possible. In fact, most of the ultrasound elements you find are in fact piezo discs... I haven't played around with them much, so I don't know for sure, but the main factor will likely be the frequency response of it... (if they work like speakers). In other words, it's possible a very large element would have too much mass to vibrate quickly enough... (i.e. a large woofer can't produce very high sounds well because it can't move fast enough)... I suspect the same may apply for the piezo elements... If so, then you just need to figure out what the "specs" of the supplied one are and rather it can do frequencies that high... (ultrasound doesn't really have to be THAT high, just out of the audiable range, and most tweeters can even do that, so it shouldn't be a problem...

As for doing a range detector, yes, but I suspect you MIGHT not have enough time to output the sound, and get things switched around in time before it comes back... at least over short distances... In other words, you might have to use TWO, one as a sender and one as a detector... But a "robot bat" might well be within your grasp... ;)

Another quick though since halloween is on my mind... I don't know how much power would be needed, but I suspect not much... I believe somewhere right around 25KHz is where sound waves will "atomize" water... (think of those ultrasonic "nebulizers")... That would be a cool little project to work on...

October 19, 2009
by srjcstud
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Thanks for the response. I'll have fun seeing what I can do with it!

January 02, 2010
by toric5
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if you do it please put it in the projects section.

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