The voltage generated by a piezo transducer can activate a digital circuit. One may build a simple demonstration switch from a piezo transducer and a 4013 D type flip flop (see Figure 12). Each time the piezo film is hit, it triggers the 4013 turning the LED on and off on alternate triggers. While this circuit works , it is unreliable, due to the waveform of the generated piezo pulse signal. To a digital circuit, a piezo-electric pulse will resemble a switch bounce with decay (see Figure 2).
Piezo electric switches have many applications (pinball machines, acceleration detectors, vibration sensors, etc). Therefore standard piezo-electric momentary pulse switches are manufactured and available (Figure 13).These switches provide clean pulses. By tapping on the end cantilever a digital pulse is generated. These swiches may be incorporated into impact sensors, counting circuits and bidirectional encoding applications.
PZ-05 and PZ-05-R Piezo-Switch Features
- Greater than 10 million switch cycles
- Impervious to moisture, dust and smoke
- Digital Output
- Low Profile
- Maintenance Free
These switches are employed in many commercial applications, in vending and slot machines as coin sensors, games, pinball machines sensors, to name a few.