piezo+arduino

Good morning,

I would like to use a piezo with an Arduino mega2560.

The transducer has to be used as transmitter and receiver.
The idea is to transmit to the piezo a sinusoidal wave amplitude 15V @ 40KHz for 200us and after sending the impulses transform the transducer in a receiver for the remaining 200us: the high terminal is grounded, while the negative terminal is set to be an input.

Attached you can find the system’s schema.

Do you have some idea on how to realize that or some link to advice me

I'd keep one pin of the piezo at Gnd and feed it with a symmetric (+-7V) signal. The input amplifier must sustain that voltage, what's not hard to accomplish. The input amplifier can use the same symmetric operating voltage.

RUE:
Good morning,

I would like to use a piezo with an Arduino mega2560.

The transducer has to be used as transmitter and receiver.
The idea is to transmit to the piezo a sinusoidal wave amplitude 15V @ 40KHz for 200us and after sending the impulses transform the transducer in a receiver for the remaining 200us: the high terminal is grounded, while the negative terminal is set to be an input.

Attached you can find the system's schema.

Do you have some idea on how to realize that or some link to advice me

Do you have some idea of the decay rate of the piezo after you stop the excitation signal?

Paul

The Arduino doesn't have a DAC so it can't put-out a sine wave... But a square wave will probably work and you don't need a linear amplifier to "boost" a square wave, so it could be an advantage.

The transducer has to be used as transmitter and receiver.
The idea is to transmit to the piezo a sinusoidal wave amplitude 15V @ 40KHz for 200us and after sending the impulses transform the transducer in a receiver for the remaining 200us: the high terminal is grounded, while the negative terminal is set to be an input.

Attached you can find the system's schema.

You need a "real" ground/reference for both the input and output. The way you've shown it you won't get any "sound" out of it because you're not getting much current through the piezo and into the high-impedance amplifier input. (All/most of the voltage will be going through into the amp instead of being dropped across the piezo.)

Realistically, you should probably be using two piezo transducers because when receiving (working like a microphone) you want a high impedance circuit but you want to drive it from a low-impedance source.

Or at least get your design working with two transducers, then you can think about adding an analog switch (or something similar) to switch between transmit & receive.

Good morning,

Thank you so much for the suggestions.

I have already tried to use the two transducers with a switch and it works.

I have to reduce the cost of the system and I am evaluating if it is possible to use only one transducer used alternately as transmitter and receiver.

Generating a square wave for me it should be ok, as well.
The transducer is used at higher frequency (40KHz) than the resonance one, so it is not so important the decay rate after stopping the excitation signal.

Could I generate a signal like in the attachment?

Thanks in advance for the help.