IR sensors

We have learned the basics of IR communication and IR LEDs, so now we will move on to making our own IR sensor.

There are various types of IR sensors, depending upon the application. Proximity sensors, obstruction sensors, and contrast sensors (used in line follower robot) are a few examples which use IR sensors.

Working mechanism

An IR sensor consists of an IR LED (which works as a transmitter) and a photodiode (which works as a receiver) pair. The IR LED emits IR radiation, which, on receiving at the photodiode dictates the output of the sensor.

There are different types of use cases for an IR sensor. For example, if we held an IR LED directly in front of the photodiode, such that almost all the radiation reaches the photodiode, this can be used as burglar alarm. So, when anyone interrupts the line of sight between the IR LED and the photodiode, this will break the continuous radiation coming from the IR LED, and we can program it to raise an alarm. This type of mechanism is also...