[Sparks333]

Hmmm... Scaled voltages for different distances? That sounds like an IR detector circuit, one without automatic gain control... I'll try to find a circuit that might fit your needs.

Sparks

Later: I looked around a bit. I think the component you want is called a phototransistor, or perhaps a photodiode. Both do largely the same thing, except a phototransistor can be biased. Basically, the more IR these things encounter, the more voltage is let through. The circuit itself really depends on what component you choose, as well as one other thing: does your microcontroller have analog-to-digital inputs? If not, then other workarounds are available, but it adds complexity. In choosing your component, keep in mind the amount of current and voltage it will encounter (look at your microcontroller datasheets for these) as well as how wide an angle you want it to see and the wavelength of the IR signal (If you don't have one already, I am betting it's around 950nm. That's a pretty common one.) Be sure that the component you get also does not respond to visible light.

Tell me what happens!

Sparks