Motion Sensor with LED's

There are at least five thick volumes of 'Encyclopedia of Electronics' or 'Electronic Circuits' or some similar name. The author/collator or whatever has a short name which begins with G. I cannot remember any more detail but go to your local public library and have a search through the books on electronics. These will be the largest, fattest, books on the shelf. There are circuits for everything in those books.

You can use a simple infrared emitter diode and a photo-transistor like detector. You need modulate the signal if you don't want to have problems with other light/infrared sources like sunlight.

PH

snipped-for-privacy@hotmail.com wrote in news:1173121235.067766.202470 @j27g2000cwj.googlegroups.com:

An excellent sensor for this application would be single pole single throw switch, as you wave your hand make contact with switch to turn on or off...

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Or the light from the lamp.

hehe. Yes. But it might be a medical application where sterilized hands shouldn't make contact... In that case, I agree with modulation for the emitter and narrow-band filtering suggestions for the receiver. Must be ICs out there for this, already.

Jon

Optical filtering would help, as well.

Jon

How?

PH

I can suggest some thoughts that were crossing my mind:

(1) Ambient light striking the detector may present a significant level of current that is unrelated to the received signal. Reducing the level, by narrowing the angle of acceptance or filtering against wavelength or using polarization to advantage can aid design and robustness to varying ambient conditions.

(2) Designing lenses for a narrow wavelength range may be easier, if they are used.

Among others. There were more crossing my mind.

Jon

Easy way would be to use the ir remote receiver module and place an IR led beside it ( pointing same direction ) running from a 40khz oscillator. The remote receiver module should have the light filter on it already. You will need also additional circuitry (flip flop and relay driver) to operate the light.