Piezo Trigger Switch circuit described here is a microcontroller-compatible shock/impact sensor switch module works on 5VDC supply. The whole circuit can be assembled on a 5×7 cm common circuit board. The piezo-ceramic element (PZ1) can also be mounted on the PCB without any difficulty. The module gives a “Logic-High” (H) output when the sensor (PZ1) detects a valid shock/impact. By default, this high signal is available for a period of near 1 second. However you can change this by modifying the value of the RC time constant components in the CMOS monostable circuit built around M7555CN (U1).
One 5mm LED (LED1) is added for effective visual indication of the output status. Imagine the fun you could have building a drum kit and then rocking the house.This circuit lets you turn your Arduino into a drum kit. Discotheque lights, winkling in tune with the bass drum bang is another application example!
Proposed circuit board wiring layout is shown here. First of all apply a thin amount of glue to the marked area on the PCB and press a plastic washer (of suitable diameter) into the glue, put aside until the glue is hard. Next, apply little glue on the top of the washer,place the piezo (with presoldered wires) and solder the wires to the circuit board. Decide how you would like to route your wires before you complete this step. It will be harder to move the wires thereafter. Now you can finish the construction by soldering remaining components as indicated in the circuit diagram. After construction, gently hit or knock the piezo sensor with your fingertipor a small hammer to test the circuit. Every time the piezo element receives a hit, the red LED lights up for near one second. Note that the piezo element can easily get damaged, so hit it mildly.