Thank you Whandall. So apparently I need the Potentiometer to enable the Arduino to print the data. Curious… what would happen without the Potentiometer? What kind of reading would you get?
You don’t need a pot. The pot is used in the example to give you an adjustable voltage to read.
The Piezo goes in the circuit in place of the pot (with a connection to ground and analog-in only).
In the circuit do I have to have a 1 megohm resistor to limit voltage to protect the board? Wouldn’t that defeat the purpose of reading the actual voltage that the sheet can make?
The resistor will reduce the signal level proportionally so you can still get a variable analog voltage.
The voltage you get from the Piezo depends on the particular piezo, the load resistance, the amount of vibration (or sound), and the frequency of the sound/vibration. These are all unknowns except the resistor, so you may have to experiment with different resistor values (or use a high-resistance pot in parallel with the Piezo).
Even if the signal is not too strong, you do need a resistor to “pull-down” the analog input to ground reference and to make sure the analog input is zero when there’s no signal from the Piezo.