Vibration alarm circuit diagram

Photocoupler

Using a piece of integrated circuit IC7556, two piezoelectric ceramics X1 and X2 and several passive electronic components to form a mechanical vibration alarm, can generate a one-minute alarm sound. As long as mechanical vibration is applied to the piezoelectric ceramic piece X1, a voltage is generated on the 10 MΩ resistor of the IC1a6 pin, and the time base circuit 7556 is triggered to cause the piezoelectric ceramic piece X2 to emit an alarm sound.

The second time base circuit IC1b generates a self-excited signal modulated by a low frequency of 5 Hz.