IR sensors: dealing with reflections?

[KenWittlief]

the sensors are very sensitive - btw they are analog and internally they have an automatic gain control that increases sensitivity to pick up weak signals while still being able to handle strong signals - the sensor needs to have a strong enough signal to recognize the 40kHz carrier, so looking at amplitude would not be easy to do.

We found the sensor picks up the beacon from all sides, the front and back - to get good directional discrimination we put them inside black radio shack 1x2x4" project boxes, with a slit at one end - the slit is vertical on the field and it acts like a pinhole camera - this greatly reduces the problem with reflections because it takes a stronger light dead ahead to reach the sensor inside the closed box through the little slit opening.

We also look at the interrupts and wait till we get three in a row before accepting the light as valid. We have not been to a regional yet, but our confidence is high.

Also, we do not use the supplied code, and we dont look at the mode 0 or 1 (or whatever its called) on the IR - we have a switch on our bot that tells the code to only look on the left side, or the right side.