IR sensor or infrared sensor actually comes in to two types one is Rx and second is TX. Also, they come in various packages size like the 5 mm package and the 3 mm package. They differ in size, and they are not up to scale. There is color difference between the Rx and TX. Now basically the Rx and TX as they say the receiving and the transmitting LEDs the transmitter actually transmit Ray’s in infrared spectrum and the Rx is designed to receive those IR spectrum rays. The receiver is darker and the transmitter is like a transparent similarly another package that is available in market. The transmitter in slightly blue shaded color while the receiver is completely transparent.
Working principle of IR
- IR LED that is a transmitter can actually transmit in infrared spectrum whenever voltage is given between its terminals it is just a diode, but it emits ray’s whenever a specific voltage is given between its two terminals that is a cathode and the anode, so we have a transmitter that receive.
The principle actually behind the working of an IR sensor is the reflectively of by an object now whenever we have any object in front of a transmitter the object tends reflect the risk that is coming from the IR sensor to back to the IR sensor so actually by using this principle we can like use this IR transmitter receiver pair for detecting object. Whenever a ray that is reflected by an object is received by an object is received by the receiver it voltage generates a voltage level at its across its terminal and this voltage level depends upon the intensity of the light that is reflected by the object.
- A transmitter and a receiver placed side by side now we can see that the IR transmitter it’s transmitting within a limited range, and it goes to a certain distance. Actually IR transmitter are not so powerful that it can traverse great distance but still it can manage at least few centimeters for detection purpose. We also have a receiver over here this is actually a very sensitive types of receiver not a common type of receiver now as there is no object present over here, so there is no reflection and that is where no object has been detected also the output between the terminals of the receiver IR LED will be like zero volt.
The object present in front of the IR transmitter here we can see that the rays have been reflected some rays can be captured by the IR receiver. Now this will in turn generate some voltage, and we will have an object detected though it may not give the accurate distance of the object but still it can manage to give the desired output that is detecting an object in its vicinity.
- We can see whenever there is a brighter object like a completely white screen it reflects more of the race whenever we have a black screen it reflects very much less than the previous one it reflects but still the quantity is too less to be detected by the IR receiver that means if a brighter screen is there it will reflect more if a darker screen is there it will reflect less in the IR range. So using this principle actually we can make a line follower which will track a bright line or a black line depending upon whatever suppose we want a black line then we will program it that whenever the IR receiver will receive the lesser amount of the rays that means the lower voltages.