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vibration sensor circuit schematic

Vibration Sensor / Detector Circuit

With the help of a simple ceramic piezo-electric detector it is possible to assemble an interesting and useful Impact sensor unit,which can be used to detect impact and vibration on doors, showcases, windows etc. The shock sensor (Ceramic piezo-electric detector) uses a “unimorph” diaphram, which consists of a piezo-electric ceramic disk laminated to a metal disk. The sensor supplies a voltage proportional to the acceleration of the impact or vibration, for example 40mV/G ie output is near 2V for 60G impact.

Here a low voltage, low current Impact sensor unit is realised using a standard ceramic piezo-electric detector which drives a monostable multivibrator (IC1) circuit to activate a npn silicon transistor (T1). Open collector output of this transistor switch can be interfaced to an external alarm/switch circuit for further processing. Since current consumption of the circuit is very low (from 5 to 6 mA only) any common 3V button cell can be used to power the sensor unit.When an impact is sensed, the monostable drives the transistor switch to ON , for a finite duration determined by the incircuit values of RC timing components R3 and C2.

Vibration/Impact Sensor Circuit Schematic

vibration sensor circuit schematic

The M74HC123 (IC1) is an high speed DUAL retriggerable CMOS MONOSTABLE MULTIVIBRATOR (MMV) fabricated with silicon gate C2MOS technology, with all inputs protected against static discharge and transient excess voltage. There are two trigger inputs, negative edge and positive edge. Here, only one monostable part with positive edge triggering (pin 2) is used. After triggering, the output maintains the monostable state for the time period determined by the external resistor R3 and capacitor C2.

19 Comments

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  • tahir

    i would like to use this circuit to enable LDO. anyone knows how it will interface with LDO enable.

    • GaryD.

      Tahir, If you take the output of T1 “C” and Tie that to your LDO input voltage and ouput T1 “E” to you enable. you will also have to put a resistor (10k) between ground and T1 so you dont cause a direct short. also grounds must be shared between your LDO and this circuit.

  • erna

    sir, can i interface this circuit with another circuit such as dc motor gate? for examnple, if i want to make a gate close after the sensor sense a vibration? what can i use to interface the circuit? really need help. tq

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  • Mukesh

    Chodu project hai

  • Brad

    I would like to take the signal from this shock sensor and transmit it via an RF signal to another unit that would count the number of signals sent. No data needed, just a 0 or 1.
    Eventually I would like to send 2 or more signals to a unit that could differentiate between the signals and count each. Could anyone please point me in the right direction? I am learning all of this as I go.

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