Thank u both for explaining me. Actually i am building a project based on the principle of IR reflection for proximity detection. For this purpose, i am using an IR LED as a transmitter and receiver units are the ones available in our TVs and VCRs(that receive the IR signal from the remote control). Any ideas about these receiver units??? The one that i have for now is from SHARP (GP1U26R series). Can anybody explain how to use it for proximity detection along with the IR LED? I have less time for its completion.