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Smart 3-Line Infrared Sensor for Robot Navigation

SKU: FA3008-1-1
Sensor Type

Infrared reflective (IR LED + phototransistor)
Number of Channels

3 independent channels
Operating Voltage

3.3V – 5V DC
Output Type

Digital (HIGH/LOW) per channel
Detection Height

5 – 15mm (recommended)
Sensitivity Adjustment

Potentiometer per channel
Indication

LED per channel
Module Dimensions

Compact PCB with mounting holes

The Smart 3-Line Infrared Sensor for Robot Navigation is a compact, high-performance sensor module designed to give robots the ability to detect and follow lines, navigate paths, and identify edges with precision. It features three independent infrared reflective sensor channels arranged in a row, each capable of detecting the presence or absence of a line beneath it. This makes it an ideal sensor suite for line-following robots, automatic guided vehicles (AGVs), maze-solving robots, and educational robotics projects.

Each of the three sensor channels consists of an infrared emitter (IR LED) and an infrared receiver (phototransistor). The emitter projects infrared light downward onto the surface, and the receiver measures the intensity of the reflected light. When the sensor is positioned over a white surface (high reflectivity), the reflected IR is strong, and the output is typically LOW. When positioned over a black line (low reflectivity), the reflected IR is weak, and the output is typically HIGH. This binary detection principle allows a robot to determine its position relative to a line and make real-time steering corrections.

The module features three independent digital outputs, one for each sensor channel. The center sensor detects the line directly ahead, while the left and right sensors detect deviation from the line, allowing the robot to steer left or right to stay on track. The outputs can be connected directly to a microcontroller’s digital input pins, enabling simple and responsive navigation logic.

Each channel is equipped with an onboard potentiometer for adjusting detection sensitivity. This allows the module to adapt to different surface colors, line contrasts, and ambient lighting conditions. LED indicators provide real-time visual feedback for each sensor channel, making it easy to verify detection during setup and troubleshooting.

The module operates from a 3.3V to 5V DC supply, making it compatible with a wide range of microcontrollers including Arduino, ESP32, STM32, and Raspberry Pi. The compact PCB design with mounting holes allows for easy integration into robot chassis and custom enclosures. The low-profile form factor ensures the sensors can be positioned close to the ground for optimal detection.

The Smart 3-Line Infrared Sensor is widely used in line-following robots, maze-solving robots, automatic guided vehicles (AGVs), edge detection systems, industrial sorting machines, and educational STEM projects. It is also popular in DIY robotics kits and maker projects where reliable line detection is essential.

Important Note: The module is not waterproof and should be mounted 5–15mm above the surface for optimal detection. Performance can be affected by ambient infrared sources (such as sunlight or incandescent lighting) and highly reflective surfaces. For best results, use the module in controlled lighting conditions and calibrate the potentiometers for your specific surface.

Whether you are building a line-following robot, an automated guided vehicle, or a STEM educational kit, the Smart 3-Line Infrared Sensor provides a reliable, affordable solution for robot navigation. It is suitable for individual makers, students, and businesses purchasing in bulk for product development or educational programs.

Features

  • Three independent IR sensor channels — Left, center, and right detection for precise line tracking

  • Digital outputs — Each channel provides a clean HIGH/LOW signal for easy MCU integration

  • Adjustable sensitivity — Onboard potentiometer for each channel to adapt to different surfaces

  • LED indicators — Real-time visual feedback for each sensor channel

  • Wide voltage range — 3.3V to 5V DC, compatible with Arduino, ESP32, STM32, and Raspberry Pi

  • Compact PCB design — With mounting holes for easy integration into robot chassis

  • Low-profile form factor — Allows close-to-ground mounting for optimal detection

  • Simple interface — Three digital outputs for direct connection to microcontroller

  • Wide application range — Line-following robots, AGVs, maze-solving, edge detection

  • Cost-effective — Affordable solution for line detection in volume production

Technical Specifications 

# Parameter Specification
1 Sensor Type Infrared reflective (IR LED + phototransistor)
2 Number of Channels 3 independent channels
3 Operating Voltage 3.3V – 5V DC
4 Output Type Digital (HIGH/LOW) per channel
5 Detection Height 5 – 15mm (recommended)
6 Sensitivity Adjustment Potentiometer per channel
7 Indication LED per channel
8 Module Dimensions Compact PCB with mounting holes

Usage

Getting Started

  1. Connect power — Supply 3.3V or 5V DC to the VCC pin and GND to ground. The power LED should light up.

  2. Connect outputs — Connect the three output pins (OUT1–OUT3) to digital input pins on your microcontroller:

    • Arduino: D2, D3, D4

    • ESP32: Any available GPIO pins

  3. Mount the module — Position the module 5–15mm above the surface, with the sensors facing down. Ensure the center sensor aligns with the line for optimal tracking.

  4. Adjust sensitivity — Place the module over a white area (or the background surface) and adjust each potentiometer until the corresponding LED just turns off. Then place it over the black line and verify the LED turns on.

  5. Upload and test — Write a simple sketch to read the three outputs and verify detection. Use the sensor states to control motor direction for line following.

Output Logic

Surface Reflected IR Output State (Typical)
White (background) Strong reflection LOW (0V)
Black (line) Weak reflection HIGH (VCC)

(Note: Output logic may vary by module variant — verify with your specific module.)

Pin Connections

Module Pin Function
VCC Power (3.3V–5V)
GND Ground
OUT1 Left sensor digital output
OUT2 Center sensor digital output
OUT3 Right sensor digital output

Example Arduino Code

cpp
#define LEFT_SENSOR 2
#define CENTER_SENSOR 3
#define RIGHT_SENSOR 4

void setup() {
  Serial.begin(9600);
  pinMode(LEFT_SENSOR, INPUT);
  pinMode(CENTER_SENSOR, INPUT);
  pinMode(RIGHT_SENSOR, INPUT);
}

void loop() {
  int left = digitalRead(LEFT_SENSOR);
  int center = digitalRead(CENTER_SENSOR);
  int right = digitalRead(RIGHT_SENSOR);

  Serial.print("L: "); Serial.print(left);
  Serial.print(" C: "); Serial.print(center);
  Serial.print(" R: "); Serial.println(right);

  // Basic line following logic
  if (center == HIGH && left == LOW && right == LOW) {
    // Move forward
  } else if (left == HIGH) {
    // Turn left
  } else if (right == HIGH) {
    // Turn right
  }

  delay(50);
}

Typical Applications

  • Line-following robots — Detect and follow a black line on a white surface

  • Maze-solving robots — Navigate complex paths using line detection

  • Automated guided vehicles (AGVs) — Follow guide paths in industrial settings

  • Edge detection — Detect the edge of a surface or material

  • Industrial sorting machines — Detect markings or labels on moving objects

  • Educational STEM projects — Teaching sensor principles and robotics

Notes for Business Buyers

  • Proven technology — Infrared reflective sensing is widely used in educational and hobby robotics.

  • Simple interface — Three digital outputs for easy integration with any microcontroller.

  • Adjustable sensitivity — Potentiometers allow adaptation to different surfaces and lighting conditions.

  • Suitable for bulk purchasing — Ideal for robotics kit manufacturers, educational institutions, and product development.

Q: What is the Smart 3-Line Infrared Sensor used for?

It is a line-following and edge detection sensor array for robot navigation, used in line-following robots, AGVs, maze-solving robots, and educational STEM projects.

Q: How many sensor channels does the module have?

It has three independent infrared reflective sensor channels — left, center, and right.

Q: What voltage does the module require?

It operates from 3.3V to 5V DC, making it compatible with Arduino, ESP32, STM32, and Raspberry Pi.

Q: How do I adjust the sensitivity?

Each channel has an onboard potentiometer. Place the module over the background surface and adjust until the LED just turns off, then verify detection over the line.

Q: What is the recommended mounting height?

Mount the module 5–15mm above the surface for optimal detection. Higher mounting may reduce detection reliability.

Q: What is the output logic?

Typically, the output is LOW over white surfaces (strong reflection) and HIGH over black lines (weak reflection). Verify with your specific module.

Q: Can I use this module outdoors?

Not recommended. Ambient infrared from sunlight can interfere with detection. Use in controlled lighting conditions for best results.

Q: Is the module waterproof?

No. The module is not waterproof and should be kept dry.

Q: How do I connect the module to an Arduino?

Connect VCC to 5V, GND to GND, and OUT1–OUT3 to digital pins D2–D4. Use digitalRead() to read each sensor.

Q: Can I purchase in bulk for a product development project?

Yes. This module is suitable for both individual users and business purchasing, including robotics kit manufacturers, educational institutions, and product development.

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