[sdiy] Photoelectric String

[Keith Daniel]

> I'm thinking of building a single-string... thing...


>Towards the bottom it'll have a set of three infrared LED'sabove and in line with the string...


Beware of picking up 60 cycle hum from lights (especially florescent). I once thought of using ultrasonic frequency modulation for the LED's and a PLL to pick out the wanted signal. 

Some IR tv remotes use a carrier type thing like this.

Good luck, take care.      kwd...