Lesson 1: Making a Basic Arduino Robot Car for Beginners

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1. Introduction

Welcome to Robotics Fundamentals! In this essential prequel lesson, you’ll be making a basic robot car using Arduino – which will be a great foundation for your coming robotics projects. You’ll learn motor control, chassis assembly, and Arduino programming while creating a manually controlled rover. Mastering this project prepares you for advanced concepts like obstacle avoidance (Lesson 2) and Bluetooth control. No prior robotics experience needed!

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2. Components Needed

• Arduino Uno (or compatible board)
• L298N Motor Driver Module
• 2x DC Gear Motors (6V-12V) with wheels
• Robot Chassis Kit (4-wheel or 2-wheel design)
• 4x AA Battery Holder (6V) or 18650 Battery Pack
• Jumper Wires (male-to-male)
• USB Cable (for Arduino programming)
• Small Screwdriver (for chassis assembly)

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3. Hardware Setup

3.1. Mechanical Assembly

1. Mount Motors: Secure DC motors to chassis using included brackets/screws
2. Attach Wheels: Press-fit wheels onto motor shafts
3. Add Castor Wheel: Install swivel castor at front/rear for balance (if 2-wheel design)
4. Secure Electronics: Use double-sided tape to mount:

• Arduino near center
• L298N near motors
• Battery holder at rear

3.2. Electrical Connections

L298N to Arduino:

L298N Pin	Arduino Pin
IN1	D5
IN2	D6
IN3	D7
IN4	D8
12V Input	Battery (+)
GND	Battery (-) & Arduino GND

Motor Connections:

• Motor A+/- → Left Motor
• Motor B+/- → Right Motor

Power Management:

• Connect Arduino VIN to L298N 5V output
• Battery (+) → L298N 12V Input
• Battery (-) → L298N GND → Arduino GND

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4. Code & How It Works

Upload This Arduino Sketch:

// Motor control pins
const int LEFT_FWD = 5;   // IN1
const int LEFT_BWD = 6;   // IN2
const int RIGHT_FWD = 7;  // IN3
const int RIGHT_BWD = 8;  // IN4

void setup() {
  // Initialize all motor pins as OUTPUTs
  for (int pin = 5; pin <= 8; pin++) {
    pinMode(pin, OUTPUT);
  }
  Serial.begin(9600);  // Start serial communication
}

void loop() {
  // Demo movement sequence
  moveForward(2000);    // Move forward for 2 seconds
  turnRight(1000);      // Turn right for 1 second
  moveBackward(2000);   // Move backward for 2 seconds
  turnLeft(1000);       // Turn left for 1 second
}

// Custom movement functions with duration parameter
void moveForward(int duration) {
  // Left motor forward
  digitalWrite(LEFT_FWD, HIGH);
  digitalWrite(LEFT_BWD, LOW);
  // Right motor forward
  digitalWrite(RIGHT_FWD, HIGH);
  digitalWrite(RIGHT_BWD, LOW);
  delay(duration);
}

void turnRight(int duration) {
  // Left motor forward (pivot)
  digitalWrite(LEFT_FWD, HIGH);
  digitalWrite(LEFT_BWD, LOW);
  // Right motor backward
  digitalWrite(RIGHT_FWD, LOW);
  digitalWrite(RIGHT_BWD, HIGH);
  delay(duration);
}

// Add moveBackward() and turnLeft() using similar patterns

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5. Programming Concepts Explained

Key Structures Used:

1. Constants:

   const int LEFT_FWD = 5;  

• Creates fixed variables for pin numbers → Improves code readability

1. Loop Initialization:

   for (int pin = 5; pin <= 8; pin++) { 
     pinMode(pin, OUTPUT); 
   }

• Efficiently configures multiple pins as outputs using a loop

1. Modular Functions:

   void moveForward(int duration) { ... }

• Encapsulates motor control logic into reusable blocks

1. Digital Signal Control:

   digitalWrite(LEFT_FWD, HIGH); // Activate forward motion

• Sets voltage state (HIGH=5V / LOW=0V) on pins to control motor direction

1. Parametric Delays:

   delay(duration); // Pauses program execution

• Allows dynamic control of movement duration via function parameters

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6. Common Troubleshooting

• Motors Spinning Backward?
  Swap motor wires on L298N terminals (A+ ↔ A-, B+ ↔ B-)
• Robot Not Moving?
• Check battery voltage (>6V for L298N)
• Verify power jumper is present on L298N (if using external power)
• Uneven Movement?
• Calibrate motor speeds by adding analogWrite(ENA, 200); (Need to wire ENA and ENB to PWM control pins-remove the black jumpers if needed)
• L298N Overheating?
• Ensure motors don’t exceed 12V rating
• Add heat sinks to L298N chip

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7. How to Go Further

1. Speed Control:
   Connect L298N ENA/ENB pins to Arduino PWM pins (3,5,6,9,10,11) and use analogWrite()
2. Wireless Control:
   Add Bluetooth (HC-05) or RF (nRF24L01) module for remote operation
3. Line Following:
   Add IR sensors for track navigation
4. Custom Movements:
   Program complex sequences like squares, circles, or zig-zags
5. Battery Monitor:
   Implement voltage sensing with analog pin

Upgrade Path:
This basic robot car becomes the foundation for Lesson 2 (Obstacle Avoidance) when you add an HC-SR04 ultrasonic sensor!

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Next Lesson Preview: Lesson 2: Transform This Car into an Obstacle-Avoiding Robot with Ultrasonic Sensors
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