[ahecht]

Just to make it clear, these sensors use near-IR, which means the light they use has a wavelength somewhere between 0.75 and 1.25 microns. Thermal IR, on the other hand, has wavelengths of between 3 and 30 microns. Heat will not be a problem.

Also, interference will probably not be a problem. The beacons (like most IR devices) emit bursts of light of varying length, which they use to send a coded message, similar to the way morse code can be used to send a text message (I am not certain what coding scheme is being used, but there are many commonly used including NEC, Sony, Toshiba Mincom, RC2000, RC5, RC6, IrDA, etc.). The Robot Controller can be programmed to look for this message, and if it isn't what it is expecting, ignore the signal.

Furthermore, each burst is not actually a solid burst of light, but is chopped up so that when the beacon is bursting, it is actually flashing 40,000 times a second. Inside each detector, a circuit called a bandpass filter removes all signals coming from light that isn't flashing near 40,000 times a second. Since most IR devices don't operate at 40kHz, most signals will never even make it to the Robot Controller.