Infra-Red Sensor commonly known as IR Sensor is nothing but a combination of IR source and a light detector called photo diode and it work on principal of transmitting light and receiving it and comparing the received amount of light with the help of a comparator LM358. IR Sensors are commonly used in detecting object and obstacles; it can also detect color. In short we can say IR sensor gives ability to autonomous robots to detect lines or nearby objects to autonomous robots. The Sensor have Digital as well as analog output also it have 4-pin header which make it easy to connect to main board via female to female jumper wire. A mounting hole lets you easily connect one or more of these on any surface.