Interface contact microphone to MCU

[Carel_Integrated]

I would like to program a MCU to be able to detect water flowing through a pipe. The requirements are:
1.) No tapping into the piping system (it should be an external device only).
2.) It should use the principle of sound measuring (audio quality does not matter).
3.) It should only detect sound emitted from the object it is in contact with.

So - I was thinking of using a piezo from a buzzer. I need help in choosing the correct piezo, I am not sure whether I should be using an internal or external drive piezo. I want it to be very sensitive. Are there any suggestions to what kind of piezo I should be looking for or specific parameters of the piezo I should be looking for?

Thanks in advance

 

[cowboybob]

What have you investigated thus far?

It sounds as though you intend to detect the actual sound of water flowing in a pipe. Is that correct? I should point out that is a very inaccurate method in that ambient, external noise could cause a false flow indication.

Ultrasonic water flow units are very effective but are extremely expensive.