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PIR Light Switch.Design note 7


PIR Based Light switches are now available to use as Motion detectors. When somebody passes through its detection area, the load such as light or electric alarm turns on. The delay time can be adjusted from 30 seconds to 3 minutes. After the delay time, the load turns off. The sensitivity can also be adjusted up to 10 meters. The unit consists of a PIR sensor module and a Tric controlled circuit for AC operation. It uses a transformerless power supply to make the unit compact. Load can be any AC device like bulb, Tubelight, CFL or an AC bell. It also has an LDR based circuit for actvating the circuit only at night. It is very easy to fix the unit and only two wires are needed for connection.It costs Rs. 350 to 550 depending on the make.
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