Piezo sensor circuit neeeds some advice

[idcrageon]

Hi,
I have a question about using piezo element to sensing slight vibration through arduino leonardo.
I want to measure a continuous vibration about ± 80mV sinusoidal sweep signal just like the picture, and analysis its FFT result.

First, when I try to measure the vibration by arduino knock sample, but I can't get any significant result.
Then, think of that the voltage piezo makes is too low .I try to add an op-amp to the circuit, but it still can not figure out significant frequency performance(it should be significant at some specific frequency).
Can anyone give me some advice about the circuit of piezo element?

Thanks,
Neil

[Paul_KD7HB]

Piezos always have a resonant frequency that they are most sensitive to. That is based on the crystal composition and geometry of the device. Are you taking that into account with your design.

Paul

[johnerrington]

@idcrageon

Then, think of that the voltage piezo makes is too low .I try to add an op-amp to the circuit, but it still can not figure out significant frequency performance(it should be significant at some specific frequency).

To measure vibration you need an accelerometer.
https://lmgtfy.app/?q=arduino+piezo+accelerometer

@idcrageon

I want to measure a continuous vibration about ± 80mV sinusoidal sweep signal

A vibration is not measured in mV. Its acceleration so (m/s)^2 as a function of time.

[idcrageon]

@Paul_KD7HB Thanks for your advice. I will take this factor into circuit consideration.
@johnerrington I think piezo element is a kind of accelerometer
and about the second I just want to express the current the piezo element generated, so I use mV to express it. Please forgive me for causing your misunderstanding.

Thanks for helping
Neil

[johnerrington]

@idcrageon

I think piezo element is a kind of accelerometer

Can you post a link to the device you are using?

@idcrageon

just want to express the current the piezo element generated, so I use mV

Oh dear. Current is not measured in mV.