Interfacing IR Sensor Module with Arduino

An infrared proximity sensor or IR Sensor is an electronic device that emits infrared light to detect objects and motion in Arduino projects. This active IR sensor module is perfect for obstacle avoidance robots, motion detection systems, and proximity sensing applications. Whether you're building your first Arduino project or need a reliable sensor for advanced robotics, this complete tutorial covers wiring, coding, and troubleshooting with step-by-step instructions.

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IR Sensor Pinout

The IR sensor has a 3-pin connector that interfaces it to the outside world. The connections are as follows:

VCC  is the power supply pin for the IR sensor which we connect to the 5V pin on the Arduino.

OUT pin is a 5V TTL logic output. LOW indicates no motion is detected; HIGH means motion is detected.

GND Should be connected to the ground of the Arduino.

How Does an IR Motion Sensor Module Work?

The working of the IR sensor module is very simple, it consists of two main components: the first is the IR transmitter section and the second is the IR receiver section. In the transmitter section, IR led is used and in the receiver section, a photodiode is used to receive infrared signal and after some signal processing and conditioning, you will get the output.

An IR proximity sensor works by applying a voltage to the onboard Infrared Light Emitting Diode which in turn emits infrared light. This light propagates through the air and hits an object, after that the light gets reflected in the photodiode sensor. If the object is close, the reflected light will be stronger, if the object is far away, the reflected light will be weaker. If you look closely toward the module. When the sensor becomes active it sends a corresponding Low signal through the output pin that can be sensed by an Arduino or any kind of microcontroller to execute a particular task. The one cool thing about this module is that it has two onboard LEDs built-in, one of which lights on when power is available and another one turns on when the circuit gets triggered.

IR Motion Sensor Module – Parts

For most of the Arduino projects, this sensor is used to detect proximity or to build obstacle avoidance robots. This Sensor is popular among beginners as these are low power, low cost, rugged, and feature a wide sensing range that can be trimmed down to adjust the sensitivity.

This sensor has three pins two of which are power pins leveled VCC and GND and the other one is the sense/data pin which is shown in the diagram above. It has an onboard power LED and a signal LED the power LED turns on when power is applied to the board the signal LED turns on when the circuit is triggered. This board also has a comparator Op-amp that is responsible for converting the incoming analog signal from the photodiode to a digital signal. We also have a sensitivity adjustment potentiometer; with that, we can adjust the sensitivity of the device. Last and finally, we have the photodiode and the IR emitting LED pair which all together make the total IR Proximity Sensor Module.

Types of IR Sensors for Arduino Projects

There are several types of IR sensors available for Arduino projects. Understanding the differences helps you choose the right sensor for your specific application:

Active IR Sensors (Proximity/Obstacle Detection)

The IR sensor module covered in this tutorial is an active IR sensor. It has both an IR transmitter (LED) and receiver (photodiode) on the same board. These sensors are perfect for building many IR sensor projects such as:

• Obstacle avoidance robots • Line following robots • Security Alarm systems • Object/Vistor counting applications • Distance measurement (2-10cm range)

Passive IR Sensors (PIR Motion Sensors)

PIR sensors detect changes in infrared radiation from moving objects, especially body heat. Unlike active IR sensors, they don't emit IR light. You can check out our how to use PIR Sensor with Arduino tutorial for more information. PIR sensors are ideal for building motion sensor projects such as:

• Motion detection systems • Burglar alarms • Automatic lighting • Energy-saving motion sensing lights 

IR Receiver Modules (Remote Control)

These sensors receive signals from IR remote controls. Popular modules like TSOP1738 decode remote control signals for Arduino projects:

• Home automation systems • Wireless communication • TV/AC remote projects • IR Remote tester circuits

IR Temperature Sensors

Non-contact temperature sensors like MLX90614 measure object temperature using IR radiation:

• Contactless thermometers • Industrial temperature monitoring • Medical applications • Food temperature checking • HVAC systems

IR Array Sensors

Multiple IR sensors arranged in arrays for advanced detection. Examples include 8-channel IR sensor arrays for line following:

• Advanced line following robots • Multi-point object detection • Industrial automation • Conveyor belt systems • Precise positioning applications

Choosing the Right IR Sensor for Your Project

• For obstacle detection: Use active IR proximity sensors (like in this tutorial)

• For motion detection: Choose PIR sensors for larger areas

• For remote control: Use IR receiver modules

• For temperature sensing: Select IR temperature sensors

• For line following: Consider IR sensor arrays

IR Sensor vs Ultrasonic Sensor - Which Should You Choose?

Both IR sensors and ultrasonic sensors are popular for Arduino distance measurement and obstacle detection. Here's a detailed comparison to help you choose the right sensor for your project:

Detection Range Comparison

IR Sensor: 2-10cm (adjustable with potentiometer) - Perfect for close-range detection

Ultrasonic Sensor (HC-SR04): 2cm-4m - Better for long-range measurements

Accuracy and Reliability

IR Sensor Advantages:

• Fast response time (almost instantaneous) • Works well with most solid objects • Less affected by air currents • Lower power consumption • Cheaper cost

IR Sensor Limitations:

• Affected by ambient light (sunlight, IR sources) • Dark or transparent objects may not be detected • Limited range • Surface texture affects performance

Ultrasonic Sensor Advantages and Limitations

Ultrasonic Advantages:

• Longer detection range (up to 4 meters) • Works with any object color • Not affected by lighting conditions • Provides exact distance measurements • Works with transparent objects

Ultrasonic Limitations:

• Slower response time • Affected by temperature and humidity • Sound-absorbing materials reduce effectiveness • Higher power consumption • Slightly more expensive

Best Use Cases for Each Sensor

Choose IR Sensor When:

• Building indoor robots with close-range detection • Creating fast-response systems • Working on battery-powered projects • Detecting objects in controlled lighting • Building line-following robots • Cost is a major factor

Choose Ultrasonic Sensor When:

• Need precise distance measurements • Working outdoors or in bright light • Detecting transparent or very dark objects • Require longer detection range • Building parking sensors or level indicators • Working with sound-reflecting surfaces

Arduino Code Complexity

IR Sensor: Simple digital read - just check HIGH/LOW state (as shown in our code above)

Ultrasonic Sensor: Requires timing calculations to convert sound travel time to distance

Power Consumption Comparison

IR Sensor: ~20mA during operation - Excellent for battery projects

Ultrasonic Sensor: ~15mA idle, ~40mA during measurement - Higher power usage

Circuit Diagram for IR Motion Sensor Module

The schematic diagram of the IR Motion sensor is shown below. The schematic itself is very simple and needs a handful of generic components to build. If you don't have a prebuilt module on hand but still want to test your project, the schematic below will come in handy.

In the schematic, we have an IR LED as Transmitter and the Photodiode as a Receiver. If an object is in front of the sensor, the reflected light from the object is received by the photodiode, and depending upon the intensity we can determine how far or how close the object is. In the schematic, you can also find an LM358 Op-Amp which is doing all the comparison work and generating the output. Other than that, there is a potentiometer that can be used to adjust the sensitivity of the IR Sensor module or the triggering distance for this module.

IR Sensor with Arduino UNO – Connection Diagram

Now that we have a complete understanding of how an IR sensor works, we can connect all the required wires to Arduino as shown below. 

Connecting the IR sensor to any microcontroller is really simple. As we know this sensor outputs a digital signal and processing this signal is very easy. There exist two methods to do so first, you can always check the port in an infinite loop to see when the port changes its state from high to low, or the other way is to do it with an interrupt if you are making a complicated project the interrupt method is recommended. Power the IR with 5V or 3.3V and connect ground to ground. Then connect the output to a digital pin D9. We have just used a Male to Female Jumper wire to connect the IR sensor module with Arduino board as shown below.

With that, you’re now ready to upload some code and get the IR Motion Sensor working. You can also check out the above module in action at the bottom of this article.

Arduino Code for Interfacing IR Motion Sensor Module with Arduino

The Arduino IR sensor module code is very simple and easy to understand. We are just basically keeping track of whether the input to pin D9 is HIGH or LOW.

We initialize our code by declaring two global variables, the first one holds the pin value where the IR sensor is connected and the second one holds the value where the LED is connected

int IRSensor = 9; // connect IR sensor module to Arduino pin D9
int LED = 13; // connect LED to Arduino pin 13

Next, we have our setup function. In the setup function, we initialize the serial with 115200 baud. Next, we print a statement to check if the serial monitor window is properly working or not, and then we initialize the IRSensor pin as input and the LED pin as output.       

void setup(){
  Serial.begin(115200); // Init Serial at 115200 Baud Rate.
  Serial.println("Serial Working"); // Test to check if serial is working or not
  pinMode(IRSensor, INPUT); // IR Sensor pin INPUT
  pinMode(LED, OUTPUT); // LED Pin Output
}

Next, we have our infinite loop. In the infinite loop, we first read the sensor pin with the digitalRead() function and store the value to sensorStatus variable. Then we check to see if the output of the sensor is high or low, if the output of the sensor is high that means no motion is detected, else motion is detected, we also print this status in the serial monitor window.          

void loop(){
  int sensorStatus = digitalRead(IRSensor); // Set the GPIO as Input
  if (sensorStatus == 1) // Check if the pin high or not
  {
    // if the pin is high turn off the onboard Led
    digitalWrite(LED, LOW); // LED LOW
    Serial.println("Motion Detected!"); // print Motion Detected! on the serial monitor window
  }
  else  {
    //else turn on the onboard LED
    digitalWrite(LED, HIGH); // LED High
    Serial.println("Motion Ended!"); // print Motion Ended! on the serial monitor window
  }
}

That is the end of our simple Arduino based IR sensor code.

Working of the IR Motion Sensor Module

The GIF shows the IR sensor module in action, you can notice the LED turn on both on the module and on the Arduino board as pointed buy the red arrows.  If you are working with an IR Motion Sensor Module for the first time then you should get a response similar to this.

Troubleshooting IR Sensor with Arduino - Common Issues

Having problems with your IR sensor Arduino project? Here are the most common issues and their step-by-step solutions:

IR Sensor Not Detecting Objects

Problem: The IR sensor module is not responding when you place objects in front of it.

Solutions:

• Check if the power LED on the IR sensor module is lit. If not, verify your VCC and GND connections.

• Adjust the sensitivity potentiometer (small screw on the module) - turn it clockwise to increase sensitivity.

• Ensure you're testing within the 2-10cm range. Objects too far or too close won't be detected.

• Try using a white piece of paper or your hand for testing - dark objects reflect less IR light.

IR Sensor Always Shows Motion Detected

Problem: The sensor output is always HIGH, even when no objects are present.

Solutions:

• Turn the sensitivity potentiometer counter-clockwise to reduce sensitivity.

• Check for ambient IR interference from sunlight, incandescent bulbs, or other IR sources.

• Verify the sensor is not pointing at reflective surfaces like mirrors or glossy walls.

• Ensure proper grounding - loose GND connections can cause false triggers.

Inconsistent IR Sensor Readings

Problem: The sensor works sometimes but gives erratic results.

Solutions:

• Add a small delay in your code loop - try adding delay(100) to stabilize readings.

• Check your jumper wire connections - loose connections cause intermittent issues.

• Use a separate 5V power supply if you're powering multiple sensors or motors.

• Shield the sensor from vibrations that might affect the potentiometer setting.

Arduino Serial Monitor Shows No Output

Problem: Your Arduino code uploads but nothing appears in the Serial Monitor.

Solutions:

• Verify the baud rate matches your code (115200 in our example).

• Check that the correct COM port is selected in Arduino IDE.

• Ensure your IR sensor output pin matches the pin defined in code (D9 in our example).

• Try uploading a simple "Hello World" program first to test serial communication.

IR Sensor Range is Too Short

Problem: The sensor only detects objects very close to it.

Solutions:

• Slowly turn the sensitivity potentiometer clockwise while testing with an object.

• Clean the IR LED and photodiode with a soft cloth - dust reduces effectiveness.

• Use lighter colored objects for testing - they reflect more IR light.

• Consider upgrading to a more sensitive IR sensor module if maximum range is still insufficient.

Similar Arduino Interfacing Tutorials

Now that you have learned how to connect an IR sensor with Arduino, you can check out the below articles for similar Arduino tutorials 

Advanced Projects using Arduino IR  Sensor Module

Previously we have used this IR sensor to build many interesting projects. If you want to know more about those topics, links are given below.

With this we are concluding our article on IR sensor module and its working with Arduino. Hope you have enjoyed reading this and learnt something useful. Now it’s time for you build something exciting on your own, lets us know what you are doing with this module in the comment section below and if you have any questions or problems feel to free to post them on our forums and we will get back to you.

Supporting Files

// Arduino IR Sensor Code
int IRSensor = 9; // connect ir sensor module to Arduino pin 9
int LED = 13; // conect LED to Arduino pin 13
void setup()
{
  Serial.begin(115200); // Init Serila at 115200 Baud
  Serial.println("Serial Working"); // Test to check if serial is working or not
  pinMode(IRSensor, INPUT); // IR Sensor pin INPUT
  pinMode(LED, OUTPUT); // LED Pin Output
}
 
void loop()
{
  int sensorStatus = digitalRead(IRSensor); // Set the GPIO as Input
 
  if (sensorStatus == 1) // Check if the pin high or not
  {
    // if the pin is high turn off the onboard Led
    digitalWrite(LED, LOW); // LED LOW
    Serial.println("Motion Ended!"); // print Motion Detected! on the serial monitor window
  }
  else
  {
    //else turn on the onboard LED
    digitalWrite(LED, HIGH); // LED High
    Serial.println("Motion Detected!"); // print Motion Ended! on the serial monitor window
  }
}