Circuit Documentation

Summary

This document provides a detailed overview of a line follower robot circuit. The circuit uses two IR sensors to detect the line and two DC motors to adjust the robot's direction. The control logic is implemented using an Arduino UNO microcontroller, which interfaces with an L298N DC motor driver to control the motors. The circuit is powered by two 18650 Li-ion batteries.

Component List

1. IR Sensor

   • Description: Infrared sensor used to detect the line.
   • Pins: out, gnd, vcc

2. L298N DC Motor Driver

   • Description: Motor driver used to control the 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

3. DC Mini Metal Gear Motor

   • Description: DC motor used for driving the robot.
   • Pins: IN1, IN2

4. 18650 Li-ion Battery x 2

   • Description: Power source for the circuit.
   • Pins: +, -

5. Arduino UNO

   • Description: Microcontroller used to control the robot.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

Wiring Details

IR Sensor 1

• Pin vcc connected to Arduino UNO 5V
• Pin gnd connected to Arduino UNO GND
• Pin out connected to Arduino UNO D8

IR Sensor 2

• Pin vcc connected to Arduino UNO 5V
• Pin gnd connected to Arduino UNO GND
• Pin out connected to Arduino UNO D9

L298N DC Motor Driver

• Pin GND connected to 18650 Li-ion Battery - and Arduino UNO GND
• Pin 5V connected to Arduino UNO Vin
• Pin 12V connected to 18650 Li-ion Battery +
• Pin IN1 connected to Arduino UNO D7
• Pin IN2 connected to Arduino UNO D4
• Pin IN3 connected to Arduino UNO D3
• Pin IN4 connected to Arduino UNO D2
• Pin ENA connected to Arduino UNO D6
• Pin ENB connected to Arduino UNO D5
• Pin OUT1 connected to DC Mini Metal Gear Motor 1 IN2
• Pin OUT2 connected to DC Mini Metal Gear Motor 1 IN1
• Pin OUT3 connected to DC Mini Metal Gear Motor 2 IN2
• Pin OUT4 connected to DC Mini Metal Gear Motor 2 IN1

DC Mini Metal Gear Motor 1

• Pin IN1 connected to L298N DC Motor Driver OUT2
• Pin IN2 connected to L298N DC Motor Driver OUT1

DC Mini Metal Gear Motor 2

• Pin IN1 connected to L298N DC Motor Driver OUT4
• Pin IN2 connected to L298N DC Motor Driver OUT3

18650 Li-ion Battery x 2

• Pin + connected to L298N DC Motor Driver 12V
• Pin - connected to L298N DC Motor Driver GND and Arduino UNO GND

Code Documentation

/*
 * Arduino Line Follower Robot
 * This code controls a line follower robot using two IR sensors and two DC motors.
 * The IR sensors detect the line and the motors adjust the robot's direction.
 */

// Pin definitions
const int irSensorLeft = 8;
const int irSensorRight = 9;
const int motorLeftForward = 7;
const int motorLeftBackward = 4;
const int motorRightForward = 3;
const int motorRightBackward = 2;
const int enableLeft = 6;
const int enableRight = 5;

void setup() {
  // Initialize IR sensor pins as inputs
  pinMode(irSensorLeft, INPUT);
  pinMode(irSensorRight, INPUT);
  
  // Initialize motor control pins as outputs
  pinMode(motorLeftForward, OUTPUT);
  pinMode(motorLeftBackward, OUTPUT);
  pinMode(motorRightForward, OUTPUT);
  pinMode(motorRightBackward, OUTPUT);
  pinMode(enableLeft, OUTPUT);
  pinMode(enableRight, OUTPUT);
  
  // Enable motors
  digitalWrite(enableLeft, HIGH);
  digitalWrite(enableRight, HIGH);
}

void loop() {
  // Read IR sensor values
  int leftSensorValue = digitalRead(irSensorLeft);
  int rightSensorValue = digitalRead(irSensorRight);
  
  // Determine motor actions based on sensor values
  if (leftSensorValue == LOW && rightSensorValue == LOW) {
    // Both sensors on the line, move forward
    moveForward();
  } else if (leftSensorValue == LOW && rightSensorValue == HIGH) {
    // Left sensor on the line, right sensor off the line, turn right
    turnRight();
  } else if (leftSensorValue == HIGH && rightSensorValue == LOW) {
    // Right sensor on the line, left sensor off the line, turn left
    turnLeft();
  } else {
    // Both sensors off the line, stop
    stopMoving();
  }
}

void moveForward() {
  digitalWrite(motorLeftForward, HIGH);
  digitalWrite(motorLeftBackward, LOW);
  digitalWrite(motorRightForward, HIGH);
  digitalWrite(motorRightBackward, LOW);
}

void turnRight() {
  digitalWrite(motorLeftForward, HIGH);
  digitalWrite(motorLeftBackward, LOW);
  digitalWrite(motorRightForward, LOW);
  digitalWrite(motorRightBackward, HIGH);
}

void turnLeft() {
  digitalWrite(motorLeftForward, LOW);
  digitalWrite(motorLeftBackward, HIGH);
  digitalWrite(motorRightForward, HIGH);
  digitalWrite(motorRightBackward, LOW);
}

void stopMoving() {
  digitalWrite(motorLeftForward, LOW);
  digitalWrite(motorLeftBackward, LOW);
  digitalWrite(motorRightForward, LOW);
  digitalWrite(motorRightBackward, LOW);
}

This code controls the line follower robot by reading the values from the IR sensors and adjusting the motor directions accordingly. The setup function initializes the pins, and the loop function continuously checks the sensor values to determine the robot's movement. The helper functions moveForward, turnRight, turnLeft, and stopMoving control the motor actions.