IR Line Follower / Proximity Sensor Module
IR Sensor module consists of an IR transmitter LED which transmits IR light, this light will then be picked up by an IR receiver LED if it gets reflect by any object in front of it. It is commonly used in Line following robots, proximity sensing, object detection etc.
It has three pins, in which two are used to power the sensor and the 3rd pins gives the output as high/low based on the proximity of the object in-front of it. The line follower sensor module also has a potentiometer to adjust the sensitivity of the sensor.