Bluetooth-Controlled Car Project

1. Components Required

L293D Motor Shield
4 DC Motors
Arduino Uno R3: For help watch the video below.

Arduino Power Wire
Battery Casing (3 Chambers)
3 Lithium-Ion Batteries
Breadboard
DC Jack
Bluetooth Module HC-05
20 Male-to-Male Wires
20 Female-to-Male Wires
4 Wheels

2. Wiring Instructions

Follow the wiring instructions to correctly assemble your Bluetooth-controlled car:

HC-05 Bluetooth Module Connections:

VCC → 5V (Arduino Uno)
GND → GND (Arduino Uno)
TX → RX (Pin 0 on Arduino)
RX → TX (Pin 1 on Arduino)

For more help watch this video:

L293D Motor Shield to Arduino Uno: Place the motor shield on top of the Arduino Uno and connect the pins correctly.
DC Motors to Motor Shield:

Motor 1 → M1 (L293D Motor Shield)
Motor 2 → M2 (L293D Motor Shield)
Motor 3 → M3 (L293D Motor Shield)
Motor 4 → M4 (L293D Motor Shield)

Power Supply: Connect the battery casing to the DC jack on the motor shield.

For more help watch this video:

4. Arduino Code


#include 

AF_DCMotor motor1(1);  // Motor 1
AF_DCMotor motor2(2);  // Motor 2
AF_DCMotor motor3(3);  // Motor 3
AF_DCMotor motor4(4);  // Motor 4

char command;

void setup() {
    Serial.begin(9600);  // Set baud rate for Bluetooth module
    Serial.println("Bluetooth-Controlled Car Ready");
}

void loop() {
    if (Serial.available()) {
        command = Serial.read();
        switch (command) {
            case 'F':
                moveForward();
                break;
            case 'B':
                moveBackward();
                break;
            case 'L':
                turnLeft();
                break;
            case 'R':
                turnRight();
                break;
            case 'S':
                stopMotors();
                break;
        }
    }
}

void moveForward() {
    motor1.setSpeed(255);
    motor2.setSpeed(255);
    motor3.setSpeed(255);
    motor4.setSpeed(255);

    motor1.run(FORWARD);
    motor2.run(FORWARD);
    motor3.run(FORWARD);
    motor4.run(FORWARD);
}

void moveBackward() {
    motor1.setSpeed(255);
    motor2.setSpeed(255);
    motor3.setSpeed(255);
    motor4.setSpeed(255);

    motor1.run(BACKWARD);
    motor2.run(BACKWARD);
    motor3.run(BACKWARD);
    motor4.run(BACKWARD);
}

void turnLeft() {
    motor1.setSpeed(150);
    motor2.setSpeed(150);
    motor3.setSpeed(255);
    motor4.setSpeed(255);

    motor1.run(BACKWARD);
    motor2.run(BACKWARD);
    motor3.run(FORWARD);
    motor4.run(FORWARD);
}

void turnRight() {
    motor1.setSpeed(255);
    motor2.setSpeed(255);
    motor3.setSpeed(150);
    motor4.setSpeed(150);

    motor1.run(FORWARD);
    motor2.run(FORWARD);
    motor3.run(BACKWARD);
    motor4.run(BACKWARD);
}

void stopMotors() {
    motor1.run(RELEASE);
    motor2.run(RELEASE);
    motor3.run(RELEASE);
    motor4.run(RELEASE);
}

5. Flutter Installation on Windows

Install Git from Git's official website.
Download and extract the Flutter SDK from Flutter's website.
Add the Flutter bin folder to your system's PATH.
Run flutter doctor in the terminal to check for any missing dependencies.

Add Dependency

Add the flutter_blue_plus package to your pubspec.yaml:

dependencies:
    flutter_blue_plus: ^1.2.0

5. Flutter Code


import 'package:flutter/material.dart';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';

class BluetoothControlApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: BluetoothControlPage(),
    );
  }
}

class BluetoothControlPage extends StatefulWidget {
  @override
  _BluetoothControlPageState createState() => _BluetoothControlPageState();
}

class _BluetoothControlPageState extends State {
  FlutterBluePlus flutterBlue = FlutterBluePlus.instance;
  BluetoothDevice? connectedDevice;
  BluetoothCharacteristic? writeCharacteristic;

  @override
  void initState() {
    super.initState();
    scanAndConnect();
  }

  void scanAndConnect() async {
    flutterBlue.startScan(timeout: Duration(seconds: 5));
    flutterBlue.scanResults.listen((results) {
      for (ScanResult result in results) {
        if (result.device.name == 'HC-05') {
          setState(() {
            connectedDevice = result.device;
          });
          connectToDevice(result.device);
          flutterBlue.stopScan();
          break;
        }
      }
    });
  }

  void connectToDevice(BluetoothDevice device) async {
    await device.connect();
    List services = await device.discoverServices();
    for (BluetoothService service in services) {
      for (BluetoothCharacteristic characteristic in service.characteristics) {
        if (characteristic.properties.write) {
          writeCharacteristic = characteristic;
          break;
        }
      }
    }
  }

  void sendCommand(String command) {
    if (writeCharacteristic != null) {
      writeCharacteristic!.write(command.codeUnits); // Send the command to the HC-05 module
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("Bluetooth RC Car Controller")),
      body: connectedDevice == null
          ? Center(child: Text("Scanning for HC-05..."))
          : Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                ElevatedButton(
                  onPressed: () => sendCommand('F'),
                  child: Text("Forward"),
                ),
                Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    ElevatedButton(
                      onPressed: () => sendCommand('L'),
                      child: Text("Left"),
                    ),
                    SizedBox(width: 10),
                    ElevatedButton(
                      onPressed: () => sendCommand('S'),
                      child: Text("Stop"),
                    ),
                    SizedBox(width: 10),
                    ElevatedButton(
                      onPressed: () => sendCommand('R'),
                      child: Text("Right"),
                    ),
                  ],
                ),
                ElevatedButton(
                  onPressed: () => sendCommand('B'),
                  child: Text("Backward"),
                ),
              ],
            ),
    );
  }
}

void main() => runApp(BluetoothControlApp());

6. Required Permissions

Add the following permissions to your app's AndroidManifest.xml file:


<manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
</manifest>