09. Wireless Communication

📦 What You’ll Need

• Arduino Uno or Nano
• HC-05 or HC-06 Bluetooth module
• Motor driver module (like L298N)
• Two DC motors with wheels
• Robot chassis
• Battery pack (7.4V Li-ion or AA x 4)
• Jumper wires
• Android phone with MIT AI2 Companion app

🔗 Wiring the Circuit

• Connect the motors to the motor driver (IN1, IN2, IN3, IN4)
• Connect ENA and ENB of the motor driver to PWM pins on Arduino (e.g., 5 and 6)
• Connect HC-05 TX to Arduino RX, and RX to TX via voltage divider
• Connect power and GND properly to motor driver and Bluetooth module

🔌 Suggested Pin Connections

💻 Sample Arduino Code

char command;

void setup() {
  Serial.begin(9600);
  pinMode(5, OUTPUT); // ENA
  pinMode(6, OUTPUT); // ENB
  pinMode(7, OUTPUT); // IN1
  pinMode(8, OUTPUT); // IN2
  pinMode(9, OUTPUT); // IN3
  pinMode(10, OUTPUT); // IN4
}

void loop() {
  if (Serial.available()) {
    command = Serial.read();

    if (command == 'F') {
      digitalWrite(7, HIGH); digitalWrite(8, LOW); // Left motor forward
      digitalWrite(9, HIGH); digitalWrite(10, LOW); // Right motor forward
    } else if (command == 'B') {
      digitalWrite(7, LOW); digitalWrite(8, HIGH);
      digitalWrite(9, LOW); digitalWrite(10, HIGH);
    } else if (command == 'L') {
      digitalWrite(7, LOW); digitalWrite(8, HIGH);
      digitalWrite(9, HIGH); digitalWrite(10, LOW);
    } else if (command == 'R') {
      digitalWrite(7, HIGH); digitalWrite(8, LOW);
      digitalWrite(9, LOW); digitalWrite(10, HIGH);
    } else if (command == 'S') {
      digitalWrite(7, LOW); digitalWrite(8, LOW);
      digitalWrite(9, LOW); digitalWrite(10, LOW);
    }
  }
}

🎮 Using the Mobile App

• Connect to the Bluetooth module via the ListPicker
• Tap the direction buttons to control your robot
• Observe how your robot responds to your commands

🚧 Debugging Tips

• Check Bluetooth pairing and serial baud rate
• Ensure motors are connected correctly (swap IN1/IN2 or IN3/IN4 if needed)
• Test commands via Serial Monitor first

🏁 What You Achieved

• Assembled a basic robot using Arduino and Bluetooth
• Built a mobile app to send directional commands
• Tested and debugged a working wireless control system

This mini project is a huge step toward building more advanced wireless robots and automation systems. You’ve now combined hardware, software, and mobile interaction into one seamless project!