How do I know which is ground and power in Piezo? I have a piezoelectric sensor. Both pins are the same length. I have one like this: Piezo picture. On the Piezo it's written muRata and 01P. How do I know which do I send to the digital pins and which to the ground? I have an Arduino Uno.
On the one I have, the shorter pin is ground. I discovered that empirically - a scientific word for "I tried it the wrong way round the first time but the magic smoke stayed inside." Afterwards I inspected it more carefully, I found a '+' embossed in the top surface nearer one side. :-o