On Thu, 12 Nov 1998, Tjaart van der Walt wrote:

> Use two diodes. Point one at the LED, and the other away from the LED.
> Use an opamp to get the difference between the two signals.

Better, pulse the transmitter and use an AC amplifier for read-out. Unless
the sun goes nova soon there should be no problems (but don't allow the
phototransistor to be saturated with sunlight in any case).

Peter