IR SENSOR MODULE
IR sensor circuit basically consist an IR LED and a Photodiode, this pair is generally called IR pair or Photo coupler.
IR Sensor module has great adaptive capability of the ambient light, having a pair of infrared transmitter and the receiver tube.
IR sensor work on the principal in which IR LED emits IR radiation and Photodiode sense that IR radiation. Photodiode resistance changes according to the amount of IR radiation falling on it, hence the voltage drop across it also changes and by using the voltage comparator (like LM358) we can sense the voltage change and generate the output accordingly.