26-10-2010, 12:35 PM
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SEISMIC SENSOR
D. MOHAN KUMAR
This circuit simulates a seismic sensor to detect vibrations/ sounds. It is very sensitive and can detect vibrations caused by the movement of animals or human beings. So it can be used to monitor protected areas to restrict entry of unwanted persons or animals. The circuit uses readily available components and the design is straightforward. A standard piezo sensor is used to detect vibrations/sounds due to pressure changes. The piezo element acts as a small capacitor having a capacitance of a few nanofarads. Like a capacitor, it can store charge when a potential is applied to its terminals. It discharges through VR1, when it is disturbed.