Interfacing KY-033 Line Tracking Sensor Module with Arduino


In this tutorial, we are Interfacing KY-033 Line Tracking Sensor Module with Arduino, The KY-033 Line Tracking module is a special sensor that uses infrared light to check if the surface in front of it reflects light or not. It is like a little eye for robots with wheels. You can adjust how sensitive it is to light using a knob, which helps it work well.

This sensor works with many different microcontrollers, like Arduino, Raspberry Pi, ESP8266, and others. It needs a power supply of 3.3V to 5V to function properly. It’s a useful tool for robots to follow lines or paths accurately.

Hardware Required

You will require the following Hardware Components for Interfacing KY-033 Line Tracking Sensor Module with Arduino.

Components#Buy From Amazon
Arduino UNO1Buy Now
KY-033 Line Tracking Sensor Module1Buy Now
9v DC Adapter (Optional)1Buy Now
Jumper Wires3Buy Now
Breadboard1Buy Now

What is KY-033 Line Tracking Module?

The KY-033 Line Tracking Sensor Module is an infrared sensor designed specifically for line tracking applications. It consists of an IR transmitter and an IR receiver that work in tandem to detect lines on the surface beneath the sensor. When the IR transmitter emits infrared light and it encounters a line, the IR receiver detects the reflected light. Based on the reflected light intensity, the sensor can distinguish between dark lines (high reflection) and the ground (low reflection). This allows the sensor to provide binary output signals indicating whether the robot is on a line or off the line.


KY-033 Line-Tracking-Sensor-Module-Pinout

Pin Configuration

OUTSignal out


The KY-033 Line Tracking module has some important parts on the front side. There is an infrared light emitter and receiver, which helps it sense things. You can adjust how sensitive it is with the potentiometer. It also has an LM393 differential comparator and a small LED that lights up to show if it’s working.

On the back side, there are four resistors. Two of them are 10 kΩ, one is 1.5 kΩ, and the other one is 220 Ω.

The module has three pins: GND (Ground), OUT (Output), and VCC (Power). The output pin is digital, which means it only gives two states: HIGH and LOW. When the module is over a black surface, it gives a HIGH signal, telling us that it found a line. When it’s over a white surface, it gives a LOW signal, which means it didn’t find a line.

If you see the little LED light up, it means the module is not detecting any line because the infrared light is coming back to the receiver.

Working voltage3.3V — 5.5V DC
Output signalTTL level (high level if line detected, low if no line detected)
Board Size1cm x 4.2cm [0.39in x 1.65in]


  1. Fast Response Time: The KY-033 sensor exhibits a fast response time, enabling real-time line detection for precise navigation.
  2. User-Friendly Interface: The sensor’s digital output provides an easy-to-understand signal for line-tracking robot control.
  3. Versatile Applications: The KY-033 module is widely used in DIY robotics, automated guided vehicles (AGVs), and maze-solving robots.

Circuit Diagram

The following circuit shows you the connection of the Interfacing KY-033 Line Tracking Sensor Module with Arduino Please make the connection carefully

KY-033 Line-Tracking-Sensor-Module-with-Arduino

Circuit Connections

To connect the KY-033 Line Tracking module to an Arduino, follow these steps:

  1. Connect the GND pin of the KY-033 module to the GND (Ground) pin on the Arduino.
  2. Connect the VCC pin of the KY-033 module to the 5V pin on the Arduino to provide power.
  3. Connect the OUT pin of the KY-033 module (the middle one) to pin 7 on the Arduino.

Make sure to double-check the pin configuration of your specific KY-033 module before connecting it to the Arduino, as some modules might have a different pin arrangement. Always verify the pinout to avoid damaging the components.


Installing Arduino IDE Software

First, you will require to Download the updated version of Arduino IDE Software and Install it on your PC or laptop. if you Learn How to install the Arduino step-by-step guide then click on how to install Arduino Button given Blow


In this Arduino sketch, we’ll read the output pin of the KY-033 every 500 milliseconds to detect lines. The signal will be HIGH for black surfaces (line detected) and LOW for white surfaces (line not detected). We’ll use the serial interface to send messages to the computer.

//For more Projects:

int sensorPin = 7;  // line detection sensor interface
int val;            // variable to store sensor reading
void setup() {
  pinMode(sensorPin,INPUT);  // define sensor as input  
  Serial.begin(9600);     // initialize serial communication with PC
void loop() {
  val = digitalRead(sensorPin); // read value from sensor
  if (val == HIGH) { 
    Serial.println("Line detected"); 
  } else { 
    Serial.println("Line NOT detected"); 

Output Result

Open Arduino IDE, select Tools > Serial Monitor, set the baud rate to 9600, and view the results.

KY-033 Line-Tracking-Sensor-Module-with-Arduino-Output-Result


  1. Line Following Robots: The primary application of the KY-033 sensor is in line following robots that can autonomously follow paths marked with lines.
  2. Maze-Solving Robots: The sensor can be used in maze-solving robots to navigate through complex mazes with defined lines as paths.
  3. Industrial Automation: The KY-033 module finds applications in industrial automation for material handling and conveyor belt systems.
  4. Educational Projects: It is an excellent choice for educational projects, teaching students about robotics and automation concepts.
  5. Automated Guided Vehicles (AGVs): In manufacturing and warehousing, the sensor can be used in AGVs for efficient and safe movement.


You have now familiarized yourself with the KY-033 Line Tracking Sensor Module and its capabilities in building line-following robots. By interfacing the sensor with Arduino UNO, you can create intelligent robots capable of autonomously navigating through predefined paths. The fast response time and user-friendly interface of the KY-033 sensor make it a versatile choice for various robotics and automation applications. Armed with this knowledge, you can now embark on exciting projects and explore the endless possibilities of line-tracking robots. So, gather your Arduino UNO, KY-033 sensor, and robot chassis, and start building your own line-following robot today.

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