Welcome to the 4WD Arduino Robot Car project repository! This is a comprehensive, open-source robotics project that implements a fully functional 4-wheel drive robot car controlled wirelessly via Bluetooth from a mobile device. Designed for enthusiasts, students, and hobbyists, this project combines hardware assembly, Arduino programming, and wireless communication to create an interactive robotics platform.
This project transforms a standard 4WD robot chassis into a smart, wirelessly controlled vehicle using the Bluetooth module,Arduino microcontroller, and motor driver circuitry.
| Feature | Description |
|---|---|
| Wireless Control | Bluetooth connectivity up to 10m range |
| 4WD System | Four-wheel drive for superior traction |
| Speed Control | PWM-based variable speed adjustment |
| Mobile Interface | Custom Android/iOS control application |
| Real-time Response | Low latency control system |
| Expandable | Easy to add sensors and modules |
| Open Source | Complete code and documentation available |
| Component | Quantity | Specification | Approx. Price |
|---|---|---|---|
| Arduino Uno/Nano | 1 | ATmega328P, 16MHz | 1000-1500 PKR |
| L298N Motor Driver | 1 | Dual H-Bridge, 2A per channel | 500-700 PKR |
| HC-05 Bluetooth Module | 1 | Bluetooth 2.0+EDR, 3.3V-5V | 700-900PKR |
| 4WD Robot Chassis | 1 | With 4 DC motors and wheels | 1800-2200 PKR |
| 18650 Battery Holder | 1 | 3-cell with switch | 400-500 |
| 18650 Batteries | 2 | 3.7V, 2000mAh+ | 600-800 |
| Jumper Wires | 20+ | Male-to-Male, Male-to-Female | 100-200 |
| Breadboard | 1 | 400/800 points | 400-500 |
| Component | Purpose |
|---|---|
| Ultrasonic Sensor (HC-SR04) | Obstacle detection |
| LED Strip | Lighting effects |
| Buzzer | Audio feedback |
| MPU6050 | Gyroscope/Accelerometer |
| OLED Display | Status monitoring |
Step 1: Assemble the 4WD chassis with motors
Step 2: Mount Arduino and L298N on chassis
Step 3: Connect motors to L298N outputs
Step 4: Wire power system and batteries
Step 5: Connect all control wires as per circuit diagram. Make these 10 connections:
• Arduino 5V → L298N +5V • Arduino GND → L298N GND
• D5 → IN1, D6 → IN2, D9 → ENA, D7 → IN3, D8 → IN4, D10 → ENB
• Battery + → L298N +12V. Battery - → L298N GND
• Arduino 5V → HC-05 VCC. Arduino GND → HC-05 GND
• Arduino TX → HC-05 RX. Arduino RX → HC-05 TX
Step 6. Upload the code. Pair Bluetooth (PIN: 1234). Test with mobile app.Step:1. Go to https://www.arduino.cc/en/software Download Arduino IDE for your operating system
Step 2: Upload Code to Arduino
• Find the code in `src` folder. Connect Arduino to computer using USB cable
• Go to Tools → Board → Select "Arduino Uno"
• Go to Tools → Port → Select correct COM port
• Open the file `src/4wd_robot_car.ino`. Or just paste the code.
• Click Upload button (right arrow icon). Wait for "Done uploading" message
Step 3: Install any of these apps:
• "Arduino Bluetooth Controller" • "Bluetooth Controller for Arduino" • "BT Control - RC Controller"
Step 4: Bluetooth Pairing
• Turn ON the robot car power. Turn ON Bluetooth
• Search for available devices. Find "HC-05" https in the list
• Tap to pair. Enter PIN: 1234. Wait for "Paired" or "Connected" status
Step 5: App Settings
• Open the Bluetooth control app. Go to Settings/Connection menu. Select "HC-05" from device list.
• Configure these settings:
• Baud Rate: 9600 • Data Bits: 8 • Stop Bits: 1 • Parity: None
• Save settings and tap "Connect"
Connect battery to car. Check these lights:
- Arduino - Green power LED = ON
- L298N - Red power LED = ON
- HC-05 - LED blinking (searching) or solid (connected).
| Problem | Solution |
|---|---|
| Car doesn't move | Check battery connection, motor wires |
| Bluetooth not connecting | Re-pair device, use PIN: 1234 |
| Only one side moves | Check motor connections on that side |
| Car moves opposite direction | Swap the two motor wires |
| Slow movement | Charge batteries, check speed setting |
| App not working | Try different Bluetooth app |
If this project helped you. So, give it a ⭐ Star on GitHub!
Built with ❤️ for the Robotics Community
Happy Building! 🛠️