laser controlled on off switch

Posted on Feb 6, 2014

This circuit is built around a 555timer using very few components. Since the circuit is verysimple, even a novice can easily build itand use it as a controlling device. A laser pointer, now easily available in the market, can be used to operate this device. This circuit has been tested in operationalconditions from a distance of500 metres and was fou

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nd to work satisfactorily though it can be controlledfrom still longer distances. Aiming(aligning) the laser beam exactly on tothe LDR is a practical problem. The circuit is very useful in switchingon/off a fan at night without gettingoff the bed. It can also be used forcontrolling a variety of other deviceslike radio or music system. The limitationis that the circuit is operational only in dark or dull-lit environments. By focussing the laser beam onLDR1 the connected gadget can be activatedthrough the relay, whereas by focussinglaser beam on LDR2 we canswitch off the gadget.

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