Apologies but I didn't happen to find ultimate answer to this.
I'm trying to make a simple piezo sensor (https://www.sparkfun.com/products/10293) which triggers something (e.g. a sound or lights up a LED) when it's pressed. This is similar to Arduino "Knock Lock" project.
However, I see there are 2 different basic ways to connect the piezo as vibration sensor:
Way 1) [as in Arduino project]
- Piezo + to 5V
- Piezo - to A0
- 1MΩ Resistor between A0 and GND
Way 2) [as in many other references on the internet]
- Piezo + to A0
- Piezo - to GND
- 1MΩ Resistor between A0 and GND
I tried both and have very different behaviours.
Way 1 seems working correctly: analogRead(A0) returns a value related to how strong the vibration is, and then decays to almost 0 (I expected 0 but it stays to 50-60ish).
Way 2 provide more of an impulse-type response, and stays at 400ish after triggered.
Are these behaviors correct and what's the proper way for piezo sensor?
Using Arduino UNO powered via USB.
