Bluetooth Controlled Robot Car

Project Overview

In this intermediate build, we integrate the L298N motor controller, DC gear motors, and an HC-05 Bluetooth module. We use a generic Bluetooth terminal app on Android to steer the rover.

Components Required

• 1x Arduino Mega or Uno
• 1x L298N Motor Driver
• 1x HC-05 Bluetooth Module
• 2x DC Gear Motors + Wheels
• 1x Robot Chassis
• 2x 18650 Batteries & Holder

Wiring Guide

Power the L298N with the battery pack. Connect the Arduino 5V/GND to the 5V out on the L298N. Wire the HC-05 TX to Arduino RX, and RX to TX (via a voltage divider for safety). Connect Motor A to IN1/IN2 (Pins 4, 5) and Motor B to IN3/IN4 (Pins 6, 7).

Source Code

char command;

void setup() {
  Serial.begin(9600); // Bluetooth default baud
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
}

void loop() {
  if (Serial.available() > 0) {
    command = Serial.read();
    if (command == 'F') { // Forward
      digitalWrite(4, HIGH); digitalWrite(5, LOW);
      digitalWrite(6, HIGH); digitalWrite(7, LOW);
    } else if (command == 'B') { // Backward
      digitalWrite(4, LOW); digitalWrite(5, HIGH);
      digitalWrite(6, LOW); digitalWrite(7, HIGH);
    } else if (command == 'S') { // Stop
      digitalWrite(4, LOW); digitalWrite(5, LOW);
      digitalWrite(6, LOW); digitalWrite(7, LOW);
    }
  }
}