IR sensor, that is infra-red sensor are a very basic type of sensors and are commonly used in any type of bots including lien follower or edge detector. Infra-red is an electromagnetic wave who wavelength is between 0.75 microns to 1000 microns which can’t be seen with our naked eye. A good thing about the IR is they come at a very low price, and comes in pair of black and white Led. As a matter of fact, TV receiver picks up IR frequency of 38khz.
There are variety of methods to use the IR receiver. One of them is using comparator which able to convert it to either HIGH or LOW. Comparator is a device that compares two signal and outputs a digital signal indicating which is larger. This method doesn’t require any kind of controller. The second method is to use the Arduino in which you can directly connect the pin of the receiver to ADC and sample the value. For those who are interested to learn more, the code is available on the project website.