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Arduino Nano Line Follower Robot with PID Control and L298N Motor Driver

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Circuit Documentation

Summary

This document provides a detailed overview of a line follower robot circuit. The circuit uses an Arduino Nano microcontroller to read values from a 5-channel IR sensor array and control two DC motors via an L298N motor driver. The motors are driven using PWM signals, and the robot follows a line using a PID control algorithm.

Component List

  1. Arduino Nano

    • Description: A small, complete, and breadboard-friendly board based on the ATmega328P.
    • Pins: D1/TX, D0/RX, RESET, GND, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11/MOSI, D12/MISO, VIN, 5V, A7, A6, A5, A4, A3, A2, A1, A0, AREF, 3V3, D13/SCK

  2. 5-channel IR array

    • Description: An array of 5 infrared sensors used to detect the line.
    • Pins: A5, A4, A3, A2, A1, VCC, GND

  3. L298N DC motor driver

    • Description: A dual H-bridge motor driver that allows control of the speed and direction of two DC motors.
    • Pins: OUT1, OUT2, 12V, GND, 5V, OUT3, OUT4, 5V-ENA-JMP-I, 5V-ENA-JMP-O, +5V-J1, +5V-J2, ENA, IN1, IN2, IN3, IN4, ENB

  4. Motor amarillo motorreductor hobby (2 units)

    • Description: A small DC motor with a gearbox, commonly used in hobby projects.
    • Pins: vcc, GND

  5. Battery 12V

    • Description: A 12V battery used to power the circuit.
    • Pins: +, -

Wiring Details

Arduino Nano

5-channel IR array

L298N DC motor driver

Motor amarillo motorreductor hobby (2 units)

Battery 12V

Documented Code

/*
 * Arduino Nano Line Follower Robot with PID Control
 *
 * This code reads values from a 5-channel IR sensor array to follow a line.
 * It uses a PID controller to adjust the speed of two DC motors via an L298N
 * motor driver. The motors are controlled using PWM signals.
 */

// Pin definitions
const int irPins[5] = {A1, A2, A3, A4, A5};
const int motorLeftPWM = 5;
const int motorRightPWM = 6;
const int motorLeftDir1 = 7;
const int motorLeftDir2 = 8;
const int motorRightDir1 = 9;
const int motorRightDir2 = 10;

// PID constants
float Kp = 1.0;
float Ki = 0.0;
float Kd = 0.0;

// PID variables
float error = 0;
float previousError = 0;
float integral = 0;
float derivative = 0;
float correction = 0;

// Motor speed
int baseSpeed = 150;
int maxSpeed = 255;

void setup() {
  // Initialize motor control pins
  pinMode(motorLeftPWM, OUTPUT);
  pinMode(motorRightPWM, OUTPUT);
  pinMode(motorLeftDir1, OUTPUT);
  pinMode(motorLeftDir2, OUTPUT);
  pinMode(motorRightDir1, OUTPUT);
  pinMode(motorRightDir2, OUTPUT);

  // Initialize IR sensor pins
  for (int i = 0; i < 5; i++) {
    pinMode(irPins[i], INPUT);
  }
}

void loop() {
  // Read IR sensor values
  int irValues[5];
  for (int i = 0; i < 5; i++) {
    irValues[i] = analogRead(irPins[i]);
  }

  // Calculate error
  error = (irValues[0] * -2 + irValues[1] * -1 + irValues[2] * 0 +
           irValues[3] * 1 + irValues[4] * 2);

  // PID calculations
  integral += error;
  derivative = error - previousError;
  correction = Kp * error + Ki * integral + Kd * derivative;
  previousError = error;

  // Calculate motor speeds
  int leftSpeed = baseSpeed - correction;
  int rightSpeed = baseSpeed + correction;

  // Constrain motor speeds
  leftSpeed = constrain(leftSpeed, 0, maxSpeed);
  rightSpeed = constrain(rightSpeed, 0, maxSpeed);

  // Set motor directions and speeds
  if (leftSpeed >= 0) {
    digitalWrite(motorLeftDir1, HIGH);
    digitalWrite(motorLeftDir2, LOW);
  } else {
    digitalWrite(motorLeftDir1, LOW);
    digitalWrite(motorLeftDir2, HIGH);
    leftSpeed = -leftSpeed;
  }
  if (rightSpeed >= 0) {
    digitalWrite(motorRightDir1, HIGH);
    digitalWrite(motorRightDir2, LOW);
  } else {
    digitalWrite(motorRightDir1, LOW);
    digitalWrite(motorRightDir2, HIGH);
    rightSpeed = -rightSpeed;
  }

  // Apply PWM to motors
  analogWrite(motorLeftPWM, leftSpeed);
  analogWrite(motorRightPWM, rightSpeed);

  // Small delay
  delay(10);
}

This code initializes the motor control and IR sensor pins, reads the IR sensor values, calculates the error for the PID controller, and adjusts the motor speeds accordingly to follow a line. The PID controller helps in maintaining a smooth and accurate line-following behavior.