I'm doing a similar IR project which uses an AVR micro to receive and 'translate' Phillips RC5 codes. The receiver is supposed to use a Radio Shack
38kHz Receiver module to capture the signals. The module works fine alone, but it fails whenever the AVR is introduced to the circuit. When this happens, the module's output pin is permanently driven to the ground state and becomes useless (this also happens when the pin is left floating). The AVR continues to function normally.