reinjon Posted July 23, 2005 Report Share Posted July 23, 2005 i am trying to build an occupancy sensor that would control lights or any electronic appliances. could you please help me. i dont know what kind of sensor to be used.... ??? actually, i dont know how to start it... any help or suggestion would be appreciated.... thanks!!!! Quote Link to comment Share on other sites More sharing options...
cobrakai Posted July 23, 2005 Report Share Posted July 23, 2005 well, the US government has made these devices for quite some time....let me give u a hint? do you know about blackbody radiation? if so, you know that the radiation from an object is proportional to the temp of that object. for instance, the human body is a pretty good temp regulator, i mean if you go too high or low you die so.....98.8 degrees C or something like that...anyway, u can use the theory of blackbody to calculate the radition the human body emits, i think its around 15 micro meters, thats one way, another is like radar but i like the first best, sort of a sniffer not broadcasting itself to the world....i know this is a spotty post but i can put up details if anyone asks? i researched this while in college its been years but can be done......or u can use the same circuit as the supermart doors use to open "magically" when you walk up to them, thought that is alike radar i think because if you duck it won't "see" youi hope this helps or at least gets you off and running! Quote Link to comment Share on other sites More sharing options...
MP Posted July 24, 2005 Report Share Posted July 24, 2005 If you are only trying to turn something on when a person enters the room, a simple motion detector can do this. If you want another idea that is not so ordinary, you could make a small particle counter. A small pump pulling the particles through a tube where they must break the small light beam of a laser diode to detector path. There are always particles floating in the air, but when people are walking into a room or doing things in a closed space, the particles start moving around and thus increase the concentration in a cubic meter of air. You can see this behavior in buildings which must monitor the dust concentration. At night when the workers go home, the concentration levels go down to near zero. When the employees start walking in the doors again in the morning, the particle counts jump and continue to fluctuate in the higher regions until people go home for the day again. This device could also be used for smoke detection as part of the fire alarm. (An added bonus).MP Quote Link to comment Share on other sites More sharing options...
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