diode rectifier start rectifying signals above 0.6V, so in your case they are doing nothing.
Your signal is so weak, bring piezo closer to noise source, my piezo is producing 200 mV when I attach it to battery drill
diode rectifier start rectifying signals above 0.6V, so in your case they are doing nothing.
Your signal is so weak, bring piezo closer to noise source, my piezo is producing 200 mV when I attach it to battery drill