Working Principle

The Bluetooth-controlled robot car works by receiving movement commands wirelessly from a smartphone. When the user presses a control button such as Forward, Backward, Left, Right, or Stop in the Bluetooth-control app, the corresponding command is transmitted through the HC-05 Bluetooth module to the Arduino UNO.

The Arduino UNO receives and interprets the Bluetooth data according to the programmed instructions. For example, when the Arduino receives a Forward command, it sends appropriate control signals to the L298N motor driver. The motor driver then supplies power to both DC gear motors so that they rotate in the direction required to move the robot forward.

For turning, the Arduino controls the two motors independently. To turn left, one motor can rotate more slowly or stop while the other continues rotating. Similarly, reversing the motor directions or changing their operation allows the robot to move backward or turn right. When the Stop command is received, the Arduino instructs the motor driver to stop the motors.

The battery pack supplies the electrical power required by the motors and control electronics. Thus, the complete working process can be summarized as Smartphone → HC-05 Bluetooth → Arduino UNO → L298N Motor Driver → DC Motors → Robot Movement. This demonstrates how wireless communication, programming, and motor control can be combined to create a simple mobile robot.