Same Day Shipping if Order Placed by 2pm

GST Invoice on All Orders

Assured Quality, 100% Genuine Components

All you need to know about IR Sensors

10th Apr 2023

A Comprehensive Guide to Working Principles and Applications of IR Sensors

In this article, we will discuss IR sensors in detail by going through their working principle and applications in different industries.

IR sensors use infrared radiation to perform a desired operation and are widely used in different applications ranging from household devices to industrial machinery. But how does an IR sensor work, and what are its applications?

This article provides a comprehensive guide on IR sensors by going through their working principle, types, and applications. In the end, the article also discusses the process of Interfacing an IR Sensor with an Arduino and sheds some light on the advantages and problems of IR sensors while providing tips for troubleshooting them.

Introduction to IR Sensors

Infrared (IR) sensors are electronic devices that detect the presence of an object or measure its temperature. Generally, IR sensors operate by detecting thermal radiation. These radiations fall under the infrared region of the electromagnetic spectrum and are invisible to the human eye. Therefore, these radiations go unnoticed in our daily life.

IR sensors are available in different types and can be used for a variety of applications, such as robotics, security systems, and other automation projects.

Working Principles of IR Sensors

The working principle of an IR sensor is based on the transmission and reception of infrared radiation. It consists of a transmitter that generates infrared radiation and a receiver that detects IR radiation.

It must be noted that the transmitter and receiver should have the same operational wavelength. This is because a receiver having a different operational wavelength will fail to detect the IR radiations emitted by the transmitter, and the system will not function as desired.


The transmitter part consists of an infrared LED (light emitting diode) which produces infrared radiation when supplied with electric current. This radiation is then directed toward the object that needs to be detected.


The receiver part of an IR sensor consists of a photodiode, a semiconductor device that is sensitive to infrared radiation. When the infrared radiation from the LED strikes the photodiode, it produces an electric current which is then amplified and converted into a voltage signal. This voltage signal is then used to trigger the desired output.

Types of IR Sensors

Based on the wavelength, size, voltage, etc., there are different types of IR sensors used for different applications. There are several types of IR sensors available on the market. The most commonly used types of IR sensors are active IR sensors and passive IR sensors.

Active Infrared Sensors

Active IR sensors are the most commonly used IR sensors. They consist of an infrared LED and a phototransistor, as described above. These sensors are used to detect the presence of objects in their vicinity.

Active IR sensors are commonly found in daily household applications like TV remotes, break beam sensors, etc., where a source sends the IR signal and a receiver detects the signal and responds accordingly.

A Laser IR sensor is also a type of active infrared sensor that is used to detect the presence of objects over long distances. They use an infrared laser beam to detect the presence of objects, and they are commonly used in military applications.

Passive Infrared Sensors

Passive IR sensors, on the other hand, only consist of the IR receiver and do not emit any radiation. Instead, they detect infrared radiation emitted by objects in their vicinity. These sensors are commonly used in security and safety systems.

There are two types of passive Infrared sensors: Thermal IR Sensors and Quantum IR Sensors.

Thermal IR Sensors

An IR temperature sensor is a type of infrared sensor that measures the temperature of objects. These sensors operate by detecting infrared thermal radiation emitted by objects in their vicinity. This radiation is then used to calculate the object's temperature.

An IR temperature sensor is commonly used to measure the temperature of objects without making physical contact with them. These sensors are commonly used in thermographic cameras, medical imaging, and industrial applications like temperature monitoring and flame detection.

Quantum IR Sensors

A quantum IR (Infrared) sensor detects and measures infrared radiation by utilizing the quantum mechanical properties of molecules. It is used to measure environmental temperature, motion, and other physical properties.

When compared to thermal IR sensors, quantum IR sensors provide better accuracy over a wider range of temperatures, higher sensitivity, and the ability to detect IR radiations over a wider frequency range. This makes quantum IR sensors suitable for industrial applications where high accuracy and reliability are of utmost importance.

Some of the popular applications of quantum IR sensors include medical imaging, industrial sensing, and remote sensing. In medical imaging, they are used to detect tumors and other abnormalities, while in industrial sensing, they are used to monitor temperature and motion. In remote sensing, they are used to measure environmental conditions, such as air temperature, humidity, and air pressure.

Advantages of IR Sensors

There are several advantages of using IR sensors. The most notable advantages of using IR sensors include:

Small and Lightweight Construction

IR sensors are small and lightweight, making them easy to install in weight-sensitive applications such as missile guiding systems. Furthermore, these sensors do not include any moving parts, which reduces the need for frequent maintenance.

Relatively Inexpensive

Infrared sensors are relatively inexpensive which makes them the ideal choice for DIY projects and other small-scale applications where cost is a decisive factor.


Although infrared sensors primarily detect infrared thermal radiations, they can be used for a variety of applications. These sensors can be used to measure the temperature of the body, detect the presence of an object in the vicinity, automated navigation systems, night-vision cameras, thermal imaging, etc.

High Accuracy

Infrared sensors are highly accurate and reliable in detecting radiation, provided that you use the right sensor and optimize its calibration. As a result, these sensors are also used in critical applications like missile guiding systems, automatic navigation, etc.

Applications of IR Sensors

IR sensors are used in a wide variety of applications. Some of the most common applications of IR sensors include:

Security Systems

IR sensors are commonly used in security systems to detect the presence of intruders. These sensors provide the ability to equip the security system with night vision, making it possible to monitor and detect any unwanted movement in the area.

Apart from night vision, infrared sensors are also used for thermal imaging of the object. In this technique, the IR sensor detects the amount of heat at different parts of an object and creates a digital image showing the temperature differences. It is most commonly used in military and industrial applications.


IR sensors are used in robotics projects to detect the presence of objects and navigate around them. In this type of IR sensor, the system sends out an IR signal and measures the amount of radiation that bounces back after striking the object. This helps the system to identify an object and navigate around them.

Long-range laser infrared sensors are also used in missile guiding systems. This system tracks the infrared radiations (generally heat) emitted by the target and navigates the missile accordingly.

Temperature Measurement

IR sensors can be used to measure the temperature of objects, such as IR thermometers that use an IR temperature sensor to measure body temperature.

Fire Safety Systems

The ability of IR sensors to detect temperature and generate an electric signal via IR Sensor Arduino makes them ideal for fire safety systems. These sensors can detect a flame and automatically turn on the fire safety system, such as water sprinklers.

Interfacing the IR Sensor with an Arduino

The IR Sensor Arduino is a popular development board for creating projects with IR sensors. This board is based on the Arduino microcontroller, which is an open-source platform for creating interactive electronic projects.

To interface the IR sensor with Arduino, start by connecting the VCC and GND pins of the sensor to the Arduino's 5V and GND pins respectively. Then connect the OUT pin of the sensor to an analog input on the Arduino. When the sensor detects an object, it will output a voltage ranging from 0 to 5 volts, depending on the distance of the object.

After connecting the sensor to the Arduino, you can start programming the controller. To begin, import the Arduino Wire library and define the pins used to connect the sensor. The voltage output from the sensor can then be read using Arduino's analogRead() function.

Finally, write the code to compare the sensor's output to a predefined value. For a motion sensor system, this value is determined by how far you want the sensor to detect. If the analogRead() function returns a value greater than the one you specified, it means the object is within the specified range. Based on this condition, you can program the system to perform the desired action.

Common Problems of IR Sensors

Although IR sensors are reliable and accurate, some common problems may arise that can affect the working of the sensor.


IR sensors can be affected by other infrared sources, such as sunlight or fluorescent lights. These interferences weaken the IR signal and make it difficult for the IR receiver to detect the original signal. As a result, the sensor malfunctions and generates improper output.

Therefore, it is always advised to use IR sensors in isolated environments or use an encasing to prevent external signals from interfering.

False detections

IR sensors may detect false signals due to electrical noise or other sources of interference. Generally, false detections are due to the high sensitivity of the sensor. For example, a poorly calibrated IR temperature sensor installed for flame detection can detect a slight increase in the temperature of the room and signal the IR sensor Arduino to activate the fire safety system.

Short range

IR sensors have a limited range and may not detect objects that are not in the line of sight. Although laser IR sensors have a larger range of operation, standard IR sensors generally work in the line of sight. A common example is a TV remote that does not operate unless the remote is pointed toward the IR receiver.

These common problems can be troublesome and hinder the proper functioning of the system, and therefore, it is important to rectify false detections by troubleshooting the sensor.

Troubleshooting Tips for IR Sensors

If you are having problems with your IR sensors, here are some troubleshooting tips that may help:

  • Make sure that the IR sensor is properly installed and connected.
  • Ensure that there are no other infrared sources in the vicinity that may be causing interference.
  • Use a shielded cable to connect the IR sensor to the microcontroller on the IR sensor Arduino.
  • Make sure that the IR sensor is in a clear line of sight with the objects that it is detecting.
  • Adjust the sensitivity of the IR sensor to ensure that it is detecting objects accurately and avoiding false detection.


Infrared sensors are a versatile and powerful sensing technology that can be used in a variety of applications. They can detect motion, temperature, pressure, humidity, and light, making them useful for different industries ranging from home automation to industrial process control. However, it is important to select the right type of IR sensor and design a proper setup to get the best results when using an IR sensor.

Evelta, as a leading marketplace for electronic components, offers a wide range of IR sensors from reputable manufacturers, ensuring genuine and reliable products for your needs. With their comprehensive selection and expert guidance, Evelta can be your trusted source of knowledge and quality IR sensors for your projects.