I bought a piezo disk and intend to use it to determine the vibration frequency of a string instrument when a note is played.
Can anyone explain how much voltage would be generated by a tuned Low E string (82Hz) compared to the high E (329Hz)?
And if I wanted to detect the frequency of the standard guitar notes I would need to sample the voltage at twice the highest frequency. High E - 329Hz. So I need to sample at 658Hz? Or 658 samples per second to an analog pin of my arduino?