This circuit uses a thin piezoelectric sensor to sense the vibrations generated by knocking on a surface; eg, a door or table. Basically, it amplifies and processes the signal from the sensor and ...

This low-cost circuit uses the piezoelectric element of a piezobuzzer as the input sensor. The piezoelectric element plate is fixed at the centre of the door wing by using a cello tape. Apply a small ...

Knock sensors are devices used in internal combustion engines to detect engine knock or detonation. The knock sensor detects vibrations and sends a signal to the engine control module (ECM), to ...