ultrasound generation

[shico90]

Hello, I was thinking about a way to generate ultrasound and i thought why can't we adjust a mcu to generate frequency above 20 khz and apply this frequency to buzzer or speaker and by that ew can have ultrasound .
that was my thinking from the theoretical point of view, but i'm geeting a feeling thatit isn't that easy. can anyone help in this?

 

[audioguru]

There are hundreds of circuits that will produce an ultrasonic signal, but a buzzer or speaker probably will not produce the sound.
You need an ultrasonic transducer to produce the high frequencies. Most ultrasonic transducers are the piezo type.

 

[shico90]

thank you for your reply

 

[Nigel Goodwin]

Hello, I was thinking about a way to generate ultrasound and i thought why can't we adjust a mcu to generate frequency above 20 khz and apply this frequency to buzzer or speaker and by that ew can have ultrasound .
that was my thinking from the theoretical point of view, but i'm geeting a feeling thatit isn't that easy. can anyone help in this?

Yes it's that easy - but bear in mind speakers don't work well at ultrasonic frequencies.

 

[shico90]

Yes it's that easy - but bear in mind speakers don't work well at ultrasonic frequencies.

really?
so i can use it with buzzer?

 

[wannaBinventor]

I think that what he's saying is that most speakers or buzzers will only have a frequency response range that is more matched to the human hearing range, not the ultrasound range . Thus, if you were going to use a speaker for this you would need to use a speaker or buzzer with a frequency response range above 20Khz. If I were you, I'd try to get a spec on the freq response range plotted against amplitute to make sure you weren't losing most of your output power in the ultrasonic ranges.

 

[Reloadron]

really?
so i can use it with buzzer?

No, because you are unlikely to find a buzzer that will produce frequencies in the ultrasonic range. If you do a simple Google of Ultrasonic Transducers you will find many devices that can respond to ultrasonic frequencies.

Note what audioguru posted:

There are hundreds of circuits that will produce an ultrasonic signal, but a buzzer or speaker probably will not produce the sound.
You need an ultrasonic transducer to produce the high frequencies. Most ultrasonic transducers are the piezo type.

Ron

 

[shico90]

yes i'm getting you now, thank you all for your replies, I searched before and I found that thing about certain transducers to generate it, but i was hoping to find an alternate solution because I searched about that transducer here in Egypt and I didn't find one, so I was trying to find anything else
anyway thank you for your help