What is an IR Sensor? IR sensor working | IR Circuit and explanation with advantages and disadvantages


IR Sensor stands for Infrared Sensor.

  • INFRARED, this term might be familiar with some people, but if you aren’t. Then I may tell you that it is a type of light spectrum which is mostly used in transmission of data or better data transmission rate and wireless transmission. But here, or in this Infrared sensor, this is not used for transmission.
  • In the Ir sensor which is of course widely popular among electronic lovers and hobbyist is used as an object detection sensor.
  • We can say that is it similar to Ultrasonic sensor but due to less range it is not as effective in distance or object detection.
  • IR Sensor is available in very different types and models also in various advanced feature but to keep it simple we’ll here explain the working of every type I have seen so far. So sit back and have fun while reading this, another interesting article based on basic electronic series list. So now let’s begin further explanation.
what is an ir sensor


  • This IR sensor has is mainly used in variuos projetcts among beginners especuially due to it’d simplicity and easy to operate.
  • This sensor can also be used as distance sensor in various projects in place of ultrasonic sensor beacuse values used in that case are digital not numeric.
  • The range can be adjudted with the help of potentiometer unlike ultrasinic sensor which needs either seperate code of modigfication in its libraray


  • One of the major disadvantage of IR sensor is that it can’t be used near fire areas. as both fire and comprises of IR radiation whch can be detected by its photodiode.This can result in malfunction of the Infrared sensor.
  • Other disadvantage is pure;y related in matter of making line follower robot. While making it you have to make sure that the surface and the tape are in purely opposite. If line is black then make sure that the floor is purely whihte or shade of while any shade darker will result in malfunctioning of sensor.
  • We can’t use this infrared sensor in the sunlight directly because ir sensor sense the infrared light it may from any of the source so the sunlight have th infrared light.
IR Sensor

Price & Availablity:

  • The IR Sensor price online is varying as you might get it at low price in offline market. While in online it may be a little higher according to the quality of the sensor. Here are some of the link provioded


  • The construction of the IR sensor is very simple, it contains an IR Led and a photodiode which together with other active and passive components make-up a complete working IR sensor.
  • There are two types of IR sensor in the market which you may come across through. The Inverting and Non-Inverting type. From the name it is clear that the output of the Infrared sensor may different from HIGH to LOW respectively.
  • The sensor also have LM393 Dual comparator whose working will be explained in further part. This component is essential as it does all the differential comparison task regarding the voltage and signal.
  • But there is also a potentiometer which can be used to trim the values to a slight range. Hence, changing the range of the sensor. Along with this, the sensor also has an onboard signal indicator. Or we can say object detection led which glows when ever the sensor detects any obstacle and object.

IR Sensor Working

  • The working of IR sensor seems to be easy but when it comes to types which I have mentioned in above text. Differs a little bit or one is directly opposite to other in terms of working of Inverting and Non-inverting comparator.
  • In the above circuit diagram which I have attached, you can have the clear picture of the circuit of the infrared sensor. Due to not very effectiveness of analog value only digital value is taken into use.
  • As soon as the power is delivered into the sensor, the IR LED which is connected to VCC with 100 Ω resistance in series start emitting IR light and can be received by the Photodiode.
  • The inverting input is connected to 10KΩ potentiometer, which is used to adjust the voltage at the inverting input.
  • The Non-inverting input is connected to the photodiode(with GND) and pulled up with 10 kΩ, which changes the voltage at the Non-inverting input when IR light falls on the photodiode.
  • The output of the comparator is connected to the D0 pin, which is pulled up with 10 kΩ.
  • The switch LED is also connected to D0 pin, which indicated the obstacle onboard sensor.
 ir sensor images

IR Sensor Applications

This is the complete explanation of the IR Sensor individually, if you find any confusion then ask in a comment. Until then, enjoy reading this type of article.


Q. What type of values is gives by IR sensor as OUTPUT?

Most of the IR sensor gives only Digital OUTPUT. While some models or versions of it which are available in the market can also give analog value. So it purely depends upon the type of sensor you have.

Q. Upto what voltage can an IR sensor be connected?

You can connect the IR sensor to a voltage range of 3.3V to 5V. Above this voltage(slightly), the sensor may work, but the values and range may differ. But below this, it might malfunction, as under voltage is not recommended,

Q. IR sensor giving reverse output at D0 Pin.

Yes, there are some versions that give reverse output on the D0 Pin. For this, the code is to be slightly modified as we have done in our Raspberry Pi tutorial.

Q. Can we use IR sensor in water?

No, you can’t use it in water, as the light will scatter in water and the sensor will function maliciously.

Q. Difference between IR Sensor and IR Array

An array is a combination of many IR sensors like 4, 6, or 10 which give the values of all at a single time. It is recommended to use Array in professional projects as it increases the accuracy of the sensor.

Q. Why IR sensor is not working in sunlight?

IR sensor works on infrared light. it transmits the ir light from the transmitter and receiver by the reciever. it uses the ir receiver which can detect infrared light. and sunlight have also the infrared spectrum which can be detected by the IR sensor. so it can be malfunction in daytime or in sunlight.

IR Sensor

1 thought on “What is an IR Sensor? IR sensor working | IR Circuit and explanation with advantages and disadvantages”

  1. Hi I am looking for a IR device who display ticket number on the display box front of customer. Like we pull instant lottery ticket , as soon as we pull lottery its show the next number on display box.


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