The TSOP1738 is an IR remote control receiver module that integrates a PIN diode and a preamplifier into a single compact package. It is designed to detect IR signals with a center frequency of 38kHz. In the absence of a signal, the output remains HIGH (+5V), and when a valid IR signal is received, the output goes LOW.
To minimize interference from ambient light sources such as sunlight or fluorescent lamps, the module includes a bandpass filter, an integrator stage, and automatic gain control. These features enhance its reliability and accuracy in IR communication and remote control applications.