For those of you that know electronics maybe you could help.
The object that I am trying to build needs to be small. It consists of a light and a receiver. So I need two parts for this item and they need to be very small. Whenever the light is around the area of the receiver the light goes off. I have seen these somewhere I just cant remember. Someone brought up the idea of a reed switch but I just need something simple.
If you have an idea please PM me
Chris

Use a door or window contact like the ones used for homes security systems. They are generally #/8"; however, you can get them smaller! It has two wires coming off of it and the switch is inside of the "contact" as we call them. When the "contact" is passed over a magnet, it can be used to turn on or turn of a light, etc.

Hope this helps!

-Bryan