Arduino Line Follower Robot With QTR-8RC Sensor

September 13, 2024 / by iFuture Technology / in Tutorial

Make a Line Follower Robot Using DRV8833, QTR-8RC, and Arduino

Line follower robots are popular beginner projects for robotics enthusiasts. They are designed to follow a line on the floor, usually marked with black tape on a white background or vice versa. In this tutorial, we will guide you through building a line follower robot using the DRV8833 motor driver, QTR-8RC sensor array, and an Arduino. This project is a great way to learn about motor control, sensor integration, and basic robotics.

Overview

A line follower robot uses sensors to detect the path and adjusts its movements accordingly. The QTR-8RC sensor array helps the robot recognize the line, while the DRV8833 motor driver controls the motors based on signals from the Arduino. This setup allows the robot to follow the line accurately and navigate turns with ease.

Components Needed

Wiring Diagram

Below is a wiring diagram to connect your components. Ensure all connections are secure to avoid any issues:

Wiring Diagram

Step-by-Step Guide

  1. Connect the Components: Start by connecting the QTR-8RC sensor array to the Arduino. Connect the sensor outputs to Arduino pins A0 to A7, VCC to 5V, and GND to ground. Connect the DRV8833 motor driver to the Arduino and the motors, making sure to connect the appropriate motor control pins.
  2. Upload the Arduino Code: Use the code below to program your Arduino. This code reads the sensor values and adjusts the motor speeds to keep the robot on track.

// Arduino code for line follower robot
#include <QTRSensors.h>

QTRSensorsRC qtrrc((unsigned char[]) {A0, A1, A2, A3, A4, A5, A6, A7}, 8); 
int motorPin1 = 5; // Motor 1 pin
int motorPin2 = 6; // Motor 2 pin
int motorPin3 = 9; // Motor 3 pin
int motorPin4 = 10; // Motor 4 pin

int threshold = 1000; // Sensor threshold value
int speed = 200; // Base speed for motors

void setup() {
    pinMode(motorPin1, OUTPUT);
    pinMode(motorPin2, OUTPUT);
    pinMode(motorPin3, OUTPUT);
    pinMode(motorPin4, OUTPUT);
    Serial.begin(9600);
}

void loop() {
    unsigned int sensorValues[8];
    qtrrc.read(sensorValues);

    int position = qtrrc.readLine(sensorValues);

    // Adjust motor speed based on line position
    if (position < 3500) { // Line is to the left
        analogWrite(motorPin1, speed);
        analogWrite(motorPin2, 0);
        analogWrite(motorPin3, speed / 2);
        analogWrite(motorPin4, 0);
    } else if (position > 4500) { // Line is to the right
        analogWrite(motorPin1, speed / 2);
        analogWrite(motorPin2, 0);
        analogWrite(motorPin3, speed);
        analogWrite(motorPin4, 0);
    } else { // Line is centered
        analogWrite(motorPin1, speed);
        analogWrite(motorPin2, 0);
        analogWrite(motorPin3, speed);
        analogWrite(motorPin4, 0);
    }

    delay(100);
}

Tips and Best Practices

  • Calibrate the sensors in a consistent lighting environment for accurate readings.
  • Ensure the robot’s wheels have good traction to avoid slipping on the line.
  • Test the robot on different line patterns to improve its performance and adaptability.

Conclusion

Building a line follower robot with DRV8833, QTR-8RC, and Arduino is a rewarding project that introduces you to basic robotics, sensor integration, and motor control. By following the steps in this guide, you can create a functional robot that follows a line accurately. With further experimentation, you can enhance the robot’s performance and tackle more complex paths.

Troubleshooting Tips

  • Ensure that the sensors are positioned correctly and are not too high or low from the line.
  • Check for loose connections, especially on the motor driver and sensor array.
  • Use the Serial Monitor to debug sensor readings and adjust thresholds accordingly.

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