Vibration sensor Alarm / Switch circuit

Vibration sensor is something that can be used to sense vibration or force that acts upon a object. Here you will see a simple vibration sensor alarm circuit which when detects any vibration or force it will sound alarm and activate a LED as an indicator to the user. This design uses the Piezo element for monitoring vibrations because of its characteristics of transforming mechanical energy into electrical energy. The conversion specification depends on the material and type of Piezo element.


  1. Op-Amp integrated circuit, LT1464 or similar
  2. Resistors 1M – 2
  3. Resistor 1k – 1
  4. Potentiometer 1M
  5. LED
  6. Piezo element – such as disc, plate, bare piezo element.
  7. Buzzer
  8. Battery, depending on the Op-Amp the value can be between 5 to 15V


The Piezo element (PZ), with no energy applied to itself generates low voltage. And here we use an Op-Amp, with a high input impedance because the volts generated by the PZ could get to hundreds of volts. We connect the voltage input from Piezo element to the inverting input of Opamp. And for the non-inverting input we connect voltage a divider. Alternatively you can also use a potentiometer of 1M  because this will allows you to adjust the intensity level of vibration that opamp needs to be activated. This will be required for the activation of the LED and Buzzer ( potentiometer symbol is used instead of buzzer in the circuit diagram ) which is connected to the output of the Op-Amp.

Basically with the Piezo element is still or without experiencing any vibration or disturbance. Adjust the potentiometer right till the LED and Buzzer turns OFF. Once the LED and Buzzer is off we can make the Piezo Element to generate a signal by moving it or hitting it so that it will experience vibration. This will make the voltage between the inputs of the Op-Amp get close to Zero or less. This forces the output of Op-Amp to low logic state. Thus this logic low state will activate the LED and Buzzer.

This circuit can also be used as a Vibration switch that activates any device or relay when sensor picks up any vibration. All you have to do is add a PNP transistor switch at the output stage of Opamp and activate any load or relay using it.

Hope this Vibration detector circuit was useful to you. Do check out other Sensor circuits in our website. Please leave your questions, feedbacks or suggestions regarding this circuit in the comment box below.

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