Upload the Code

Code upload

Open up your Arduino IDE.

Connect your USB cable to your PC and Arduino board.

Please ensure that the TX and RX for the Bluetooth module is not connected. If this is connected then the code upload will fail.

Copy the code below to a new Arduino project and Click the upload button

// Motor A (Right) connections
#define ENA 9       // Enable/speed motor Right wheels
#define IN_1  8    // Right wheels
#define IN_2  7    // Right wheels

// Motor B (Left) connections
#define ENB 3       // Enable/speed motor Left Right
#define IN_3  5    		// Left wheels
#define IN_4  4    		// Left wheels

int command; 			      //Int to store app command state.
int speedCar = 255; 		// 50 - 255.

void setup() {

  pinMode(ENA, OUTPUT);
  pinMode(ENB, OUTPUT);
  pinMode(IN_1, OUTPUT);
  pinMode(IN_2, OUTPUT);
  pinMode(IN_3, OUTPUT);
  pinMode(IN_4, OUTPUT);

  Serial.begin(9600);

}

void goAhead() {

  digitalWrite(IN_1, HIGH);
  digitalWrite(IN_2, LOW);
  analogWrite(ENA, speedCar);

  digitalWrite(IN_3, LOW);
  digitalWrite(IN_4, HIGH);
  analogWrite(ENB, speedCar);
}

void goBack() {

  digitalWrite(IN_1, LOW);
  digitalWrite(IN_2, HIGH);
  analogWrite(ENA, speedCar);


  digitalWrite(IN_3, HIGH);
  digitalWrite(IN_4, LOW);
  analogWrite(ENB, speedCar);
}

void goRight() {

  digitalWrite(IN_1, HIGH);
  digitalWrite(IN_2, LOW);
  analogWrite(ENA, speedCar);


  digitalWrite(IN_3, LOW);
  digitalWrite(IN_4, LOW);
  analogWrite(ENB, speedCar);
}

void goLeft() {

  digitalWrite(IN_1, LOW);
  digitalWrite(IN_2, LOW);
  analogWrite(ENA, speedCar);

  digitalWrite(IN_3, LOW);
  digitalWrite(IN_4, HIGH);
  analogWrite(ENB, speedCar);

}

void stopRobot() {

  digitalWrite(IN_1, LOW);
  digitalWrite(IN_2, LOW);
  analogWrite(ENA, speedCar);


  digitalWrite(IN_3, LOW);
  digitalWrite(IN_4, LOW);
  analogWrite(ENB, speedCar);
}

void loop() {

  if (Serial.available() > 0) {
    command = Serial.read();
    stopRobot(); 			//Initialize with motors stopped.

    switch (command) {
      case 'F': goAhead(); break;
      case 'B': goBack(); break;
      case 'L': goLeft(); break;
      case 'R': goRight(); break;
      case '0': speedCar = 100; break;
      case '1': speedCar = 115; break;
      case '2': speedCar = 130; break;
      case '3': speedCar = 145; break;
      case '4': speedCar = 160; break;
      case '5': speedCar = 175; break;
      case '6': speedCar = 190; break;
      case '7': speedCar = 205; break;
      case '8': speedCar = 220; break;
      case '9': speedCar = 235; break;
      case 'q': speedCar = 255; break;

    }
  }
}

Once the code is uploaded successfully, connect RX of Hc-05 to TX of Arduino and TX of Hc-05 to RX of Arduino

Install the Arduino App

Install the Arduino Bluetooth RC Car App.