Electronic Sensor

I am looking for a circuit diagram which dehaves like a senor where any object comes in front of it (say within 2 feets).. the circuit will glow a light which is attached to it.
Thanks - Hitesh

Use reflected IR light. You can do that very easily with a simple microcontroller (e.g., 12F509) or with discrete components, such as a 556 dual oscillator and a 567 demodulator. What resources do you have available? Are you wiling to take on learning enough Assembly to modify the program for the microcontroller?
John

Thanks John for replying...
I am a student and this is kind of my first project. I am not very familiar with the ICs and modulators. It will be helpful if you can send me some link or any circuit diagram.

Here is a schematic for a LM556/LM567 based reflected IR
detector.

Check this link for a microcontroller-based system:
http://users.frii.com/dlc/robotics/projects/botproj.htm

John

Edit: I can't get the schematic uploaded right now. Tried X3. It comes up blank. Will try later. John

Edit: Here's the schematic in gif. John