It is easy to construct a Laser based Relay activator to operate Alarm systems or to switch on CCTV or Auto Camera when there is any attempt of theft. It can be used to guard, doors, entry passages etc. The circuit uses Laser beam so that the range of the circuit is more than 10 meters and there is no false triggering.
Laser diode is similar to LED and emits Monochromatic narrow laser beam that passes long distance through air. The Laser diode requires 3 volts and around 100 mA current for getting maximum range. So the current limiting resistor must be selected as per the range. A China make low cost laser torch can be used for the purpose.
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