The Grove - IR (Infrared) Receiver is used to receive infrared signals and also used for remote control detection. The IR detector has a demodulator inside that looks for modulated IR at 38 kHz.
The Infrared Receiver can receive signals well within 10 meters. If more than 10 meters, the receiver may not receive consistent signals.
Use the two Grove IR modules together - this Infrared Receiver and the Infrared Emitter!