source= http://www.piclist.com/piclist/2003/11/26/155233a.txt?

jpower says:
>
>       One way would be to shine an LED on the
> phototransistor from the side, and      adjust its intensity
> to keep the output at a certain level. If the circuit driving
> the      LED is slowed by an RC time constant, an increase in
> light would temporarily      raise the output before the
> circuit readjusted itself.
>

Ah! Very nice... Something like this?

    V+
    |
    R
    +---C--.
   /       |
  pT      LED
   \       |
    |      |
   gnd    gnd


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