touchless light switch

[naveenon90]

i am doing a small project called touchless light switch.i got some info from other sources but i could not follow it.if anybody having any info or circuit diagram's etc.. plz reply me.


IT'S URGENT !!!!!!!!!!!!!

 

[akg]

some more details will help

 

[stevez]

I have no schematic to offer though I do have information. Many of the imported touch lamps (I live in US) seem to be very poor designs in terms of radio frequency interference. The appear to have some kind of oscillator running constantly, regardless of whether in the on or off state. The noise ruins reception of AM and shortwave broadcasts. If I am listening on shortwave I have to call my neighbor and ask her to unplug her lamp.

Thankfully these poor designs are also incredibly sensitive to RF transmissions. With a 5 watt SSB transmitter I can affect touch lamps within a few hundred yards.

For whatever reason it seems that the designers choose a circuit that has a square wave, low frequency (maybe a few hundred kHz) oscillator running. You might use that as a guide. You might also seek to improve on that by eliminating the RF issues.

 

[redserpentone]

if it is urgent and important try any security systems store that supplies to companies like ADT, Ogden, blah on the yellow pages
Infrared detectors can be easily configured: cut light path, detect light reflected, they all come with the proper circuitry just install and check.

rs1