Project Documentation

Arduino-Controlled Line-Following Robot with Dual IR Sensors and L298N Motor Driver

Circuit Documentation

Summary

The circuit in question is designed to control a pair of DC motors using an Arduino UNO microcontroller and an L298N DC motor driver. The system also includes two infrared sensors for detecting track lines, which are used to guide the motors' actions. A 9V battery provides the power source for the motor driver and indirectly for the Arduino through voltage regulation.

Component List

Arduino UNO

Microcontroller board based on the ATmega328P
It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

9V Battery

Standard 9V battery used to provide power to the circuit.

DC Motor (x2)

Electric motor that runs on direct current (DC) electricity.
Used for creating rotational motion in the system.

L298N DC Motor Driver

A motor driver module capable of driving two DC motors or one stepper motor.
It has two H-bridges and can handle a substantial current.

IR Sensor (x2)

Infrared sensors used for line tracking.
Each sensor has an output that goes high or low depending on the presence of a line.

Wiring Details

Arduino UNO

5V pin provides power to both IR sensors.
GND pin is connected to the ground of the IR sensors, L298N motor driver, and the negative terminal of the 9V battery.
Vin pin is connected to the 5V pin of the L298N motor driver.
Digital pins D13, D12, D11, D10, D6, and D5 are connected to the IN2, IN1, IN4, IN3, ENA, and ENB pins of the L298N motor driver, respectively.
Digital pins D4 and D2 are connected to the output of the IR sensors.

9V Battery

+ terminal is connected to the 12V pin of the L298N motor driver.
- terminal is connected to the ground of the circuit.

DC Motor #1

pin 1 is connected to OUT2 of the L298N motor driver.
pin 2 is connected to OUT1 of the L298N motor driver.

DC Motor #2

pin 1 is connected to OUT4 of the L298N motor driver.
pin 2 is connected to OUT3 of the L298N motor driver.

L298N DC Motor Driver

OUT1, OUT2, OUT3, and OUT4 are connected to the respective pins of the DC motors.
12V pin is connected to the positive terminal of the 9V battery.
GND pin is connected to the ground of the circuit.
5V pin is connected to the Vin pin of the Arduino UNO.
ENA, IN1, IN2, IN3, IN4, and ENB are connected to the respective pins of the Arduino UNO.

IR Sensor #1

out pin is connected to D4 on the Arduino UNO.
gnd pin is connected to the ground of the circuit.
vcc pin is connected to 5V on the Arduino UNO.

IR Sensor #2

out pin is connected to D2 on the Arduino UNO.
gnd pin is connected to the ground of the circuit.
vcc pin is connected to 5V on the Arduino UNO.

Documented Code

// Definition of pins for motor speed control
// Activates ENA (enable a) and ENB (enable b)
int velmotor1 = 6;
int velmotor2 = 5;

// Definition of motor control pins In1, In2, In3, In4
int motor1A = 13;
int motor1B = 12;
int motor2C = 11;
int motor2D = 10;

// Infrared sensors - left and right
// Will detect the track to activate functions
int infrapinr = 2;
int infrapinl = 4;

// Variable to capture the values - 0 for light ground and 1 for dark ground
int valorinfrar = 0;
int valorinfral = 0;

// Initial configuration
void setup() {
  Serial.begin(9600);
  delay(1000);
  // Set the mode of the infrared sensor pins
  pinMode(infrapinr, INPUT);
  pinMode(infrapinl, INPUT);
  
  // Set the mode of the motor control pins
  pinMode(motor1A, OUTPUT);
  pinMode(motor1B, OUTPUT);
  pinMode(motor2C, OUTPUT);
  pinMode(motor2D, OUTPUT);
  pinMode(velmotor1, OUTPUT);
  pinMode(velmotor2, OUTPUT);
  
  // Set the motor speed between 150/255
  analogWrite(velmotor1, 150);
  analogWrite(velmotor2, 150);
  
  // Configure the direction of rotation
  digitalWrite(motor1A, LOW);
  digitalWrite(motor1B, LOW);
  digitalWrite(motor2C, LOW);
  digitalWrite(motor2D, LOW);
}

void loop() {
  // Read the values of the infrared sensors - 0 for light ground and 1 for dark ground
  valorinfrar = digitalRead(infrapinr);
  valorinfral = digitalRead(infrapinl);
  Serial.println(valorinfrar);
  Serial.println(valorinfral);

  // Four scenarios
  // Straight ahead
  if (valorinfrar == 0 & valorinfral == 0) {
    Serial.println("none on line");
    digitalWrite(motor1A, HIGH);
    digitalWrite(motor2D, HIGH);
    delay(20);

    digitalWrite(motor1A, LOW);
    digitalWrite(motor2D, LOW);
    delay(20);
  }
  // Line found on the right side
  if (valorinfrar == 1 & valorinfral == 0) {
    Serial.println("right on line");
    digitalWrite(motor1A, LOW);
    digitalWrite(motor2D, LOW);
    delay(25);

    digitalWrite(motor1A, HIGH);
    digitalWrite(motor2D, LOW);
    delay(20);
  }
  // Line found on the left side
  if (valorinfrar == 0 & valorinfral == 1) {
    Serial.println("left on line");
    digitalWrite(motor1A, LOW);
    digitalWrite(motor2D, LOW);
    delay(25);

    digitalWrite(motor1A, LOW);
    digitalWrite(motor2D, HIGH);
    delay(20);
  }
  // Line found on both sides
  if (valorinfrar == 1 & valorinfral == 1) {
    Serial.println("both on line");
    // Stop the motors
    digitalWrite(motor1A, LOW);
    digitalWrite(motor1B, LOW);
    digitalWrite(motor2C, LOW);
    digitalWrite(motor2D, LOW);
  }
}

This code is responsible for reading the infrared sensors and controlling the motors based on the sensor readings. It sets up the motor control pins and the infrared sensor pins, defines the initial motor speed, and then enters a loop where it reads the sensor values and controls the motors accordingly. The comments within the code provide additional context for each section and operation.