Infrared Autoswitch
Approx construction cost US$30.50
Simply waving your hand near this versatile IR switch will cause lights to switch on for a timed period. If you stay in the area the unit will remain triggered.
The infra-red autoswitch described in this project will, no doubt, find many applications, but it was designed initially to switch on the concealed lighting around a set of kitchen units. Simply waving your hand near the unit will cause the lights to switch on for a timed period. Also, if you stay in the area the unit will remain triggered.
The sensor employed here is similar to the auto-switches used in up-market public wash handbasins and handdriers, where the water or air is switched on when your hand is in place. It is important not to make the unit too sensitive otherwise false triggering will occur. The system is triggered when your hand is about 30cm from the unit. The prototype was concealed underneath a kitchen cupboard, the distance between the unit and the worksurface being too large to cause false triggering.
The project was designed for maximum ease of assembly and fitting, with all components including the transformer being housed on a printed circuit board (p.c.b.). The only connections required are the mains supply input, and lighting output.
More details on this construction project can be found in the July 2002 issue of EPE Online, the world's first web-delivered electronics and computing hobbyist magazine.
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