When I first decided to look into a better way to fix this, I was thinking of making something that I could add to the outside that would act as a light pipe, to get the IR light past the little black barrier that's glued inside the clear plastic cover.
After opening the assembly, I was thinking of removing the black barrier, but that wouldn't be reversible. That's when I noticed the cavity that would hold the LED and PhotoSensor.
If anyone is concerned with the intensity, they could put a small square of paper between the two devices. That would diffuse and attenuate the light somewhat. Personally, I'm not concerned with my sensors being damaged.
I'm very surprised that iRobot
hasn't listened to their customers, and provided a way to disable the cliff sensors for those who have black carpets. Even an un-documented internal switch, on the circuit board would be nice. They don't even have to acknowledge it in the manual. Just make it available for those of us who need them disabled. These kludges shouldn't be necessary.