Building a Smart Bluetooth Car with Arduino and Motor Driver HW-130

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a Bluetooth module like the HC-05 or HC-06, which communicates over serial. The mobile app can send simple commands (like “F” for forward, “B” for backward, “S” for stop, etc.) via Bluetooth to control the motors.

Steps:

  1. Use SoftwareSerial to communicate with Bluetooth.
  2. Map incoming Bluetooth commands to motor actions.
  3. Modify the AFMotor control to respond to Bluetooth commands.

Motor Driver Shield (HW-130) Connections:

  • Motor 1 (M1) is connected to M1 terminals on the motor driver shield.
  • Motor 2 (M2) is connected to M2 terminals on the motor driver shield.
  • Motor 3 (M3) is connected to M3 terminals on the motor driver shield.
  • Motor 4 (M4) is connected to M4 terminals on the motor driver shield.
  • Bluetooth Module (HC-05/HC-06):
    • VCC -> 5V on Arduino
    • GND -> GND on Arduino
    • TXD -> Pin 10 (RX on SoftwareSerial)
    • RXD -> Pin 11 (TX on SoftwareSerial)

Explanation of the Code:

#include <AFMotor.h> // Install "Adafruit Motor Shield" driver
#include <SoftwareSerial.h> // It comes bundled with the Arduino IDE by default.

// Define motor objects using AFMotor library
AF_DCMotor motor1(1, MOTOR12_1KHZ);  // Motor 1
AF_DCMotor motor2(2, MOTOR12_1KHZ);  // Motor 2
AF_DCMotor motor3(3, MOTOR34_1KHZ);  // Motor 3
AF_DCMotor motor4(4, MOTOR34_1KHZ);  // Motor 4

// Set up SoftwareSerial for Bluetooth communication
SoftwareSerial BTSerial(10, 11);  // RX, TX (you can change pins as needed)

void setup() {
  // Start Bluetooth serial communication
  BTSerial.begin(9600); // Bluetooth module baud rate
  Serial.begin(9600);   // Debugging serial monitor

  // Initialize motors to stop
  motor1.setSpeed(255);
  motor2.setSpeed(255);
  motor3.setSpeed(255);
  motor4.setSpeed(255);
  
  motor1.run(RELEASE);
  motor2.run(RELEASE);
  motor3.run(RELEASE);
  motor4.run(RELEASE);
}

void loop() {
  // Check if data is available from Bluetooth module
  if (BTSerial.available()) {
    char command = BTSerial.read();  // Read incoming Bluetooth data

    // Display the received command on the serial monitor (for debugging)
    Serial.println(command);

    // Check for specific commands to control motors
    switch (command) {
      case 'F':  // Forward command
        moveForward();
        break;
      case 'B':  // Backward command
        moveBackward();
        break;
      case 'L':  // Left command (turn left by moving motor 1 and motor 2 in opposite directions)
        turnLeft();
        break;
      case 'R':  // Right command (turn right by moving motor 3 and motor 4 in opposite directions)
        turnRight();
        break;
      case 'S':  // Stop all motors
        stopMotors();
        break;
      default:
        stopMotors();  // Default stop if invalid command
        break;
    }
  }
}

// Function to move all motors forward
void moveForward() {
  motor1.run(FORWARD);
  motor2.run(FORWARD);
  motor3.run(FORWARD);
  motor4.run(FORWARD);
}

// Function to move all motors backward
void moveBackward() {
  motor1.run(BACKWARD);
  motor2.run(BACKWARD);
  motor3.run(BACKWARD);
  motor4.run(BACKWARD);
}

// Function to turn the vehicle left (motor 1 and motor 2 in opposite directions)
void turnLeft() {
  motor1.run(FORWARD);  // Motor 1 moves backward
  motor2.run(FORWARD);   // Motor 2 moves forward
  motor3.run(RELEASE);   // Motor 3 moves forward
  motor4.run(RELEASE);  // Motor 4 moves backward
}

// Function to turn the vehicle right (motor 3 and motor 4 in opposite directions)
void turnRight() {
  motor1.run(RELEASE);   // Motor 1 moves forward
  motor2.run(RELEASE);  // Motor 2 moves backward
  motor3.run(FORWARD);  // Motor 3 moves backward
  motor4.run(FORWARD);   // Motor 4 moves forward
}

// Function to stop all motors
void stopMotors() {
  motor1.run(RELEASE);
  motor2.run(RELEASE);
  motor3.run(RELEASE);
  motor4.run(RELEASE);
}
  1. SoftwareSerial BTSerial(10, 11);
    • This initializes a SoftwareSerial port for Bluetooth communication on pins 10 (RX) and 11 (TX).
    • Adjust these pins based on your setup. If you’re using a different set of pins for Bluetooth communication, modify it accordingly.
  2. Bluetooth Commands:
    • The mobile Bluetooth control app sends specific commands via Bluetooth, which are received in the loop().
    • Based on the command received, the motors are controlled accordingly:
      • 'F' = Move forward
      • 'B' = Move backward
      • 'L' = Turn left (one motor forward, one motor backward)
      • 'R' = Turn right (one motor backward, one motor forward)
      • 'S' = Stop all motors
  3. Motor Control Functions:
    • moveForward(), moveBackward(), turnLeft(), turnRight(), and stopMotors() are functions that control the motors using the AFMotor library.

Using a Mobile Bluetooth Control App:

  1. Install a Bluetooth control app (such as the Arduino Bluetooth Controller or Bluetooth RC Controller from the Google Play Store or Apple App Store).
  2. Pair the Bluetooth module with your phone via Bluetooth settings.
  3. Use the app to send commands like “F”, “B”, “L”, “R”, or “S” to control the car.