Robo-Car-Racing

ESP32 Robot Car with Bluetooth Control

A 4-motor robot car controlled via Bluetooth using ESP32, HC-06 Bluetooth module, and BTS7960 motor drivers. Features variable speed control (0-100%) and 8-direction movement capabilities.

Project Overview

This project implements a fully functional Bluetooth-controlled robot car with:

• 4x 12V 500 RPM DC Gear Motors - Two motors per side (left and right)
• 2x BTS7960 Motor Drivers - One driver for left side, one for right side
• ESP32 Microcontroller - Main control unit
• HC-06 Bluetooth Module - Wireless communication interface
• Variable Speed Control - 0-100% in 10% increments
• 8-Direction Movement - Forward, backward, left, right, and 4 diagonal directions

Components List

Component	Quantity	Specifications
ESP32 Development Board	1	Any ESP32 variant (ESP32-WROOM, ESP32-DevKit, etc.)
HC-06 Bluetooth Module	1	3.3V logic, 9600 baud default
BTS7960 Motor Driver	2	High-current H-bridge driver
12V DC Gear Motor	4	500 RPM, suitable current rating
12V Battery Pack	1	Sufficient capacity for motors (2-5A per motor)
5V Power Supply	1	For ESP32 (USB or regulated supply)
Jumper Wires	As needed	22-24 AWG for signals, 18-20 AWG for motor power
Breadboard/PCB	1	For prototyping or permanent mounting

Features

• ✅ Bluetooth wireless control via HC-06 module
• ✅ Variable speed control (0-100% in 10% steps)
• ✅ 8-direction movement (forward, back, left, right, 4 diagonals)
• ✅ Smooth PWM-based motor control
• ✅ Emergency stop function
• ✅ Real-time command processing
• ✅ Serial debugging support

Quick Start Guide

1. Hardware Setup

1. Review Connections

   • Read CONNECTIONS.md for detailed wiring instructions
   • Ensure all components are properly connected
   • Verify all GND connections are common (shared ground)

2. Power Supplies

   • Connect ESP32 via USB or 5V regulated supply
   • Connect 12V battery pack to both BTS7960 modules (B+ and B-)
   • Critical: Connect 12V battery negative to common GND

3. Initial Check

   • Power on ESP32 and verify it initializes
   • Check Serial Monitor (115200 baud) for startup messages
   • Verify HC-06 LED is blinking

2. Software Setup

1. Install Arduino IDE

   • Download from arduino.cc
   • Install ESP32 board support:
     • File → Preferences → Additional Board Manager URLs
     • Add: https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
     • Tools → Board → Boards Manager → Search "ESP32" → Install

2. Upload Code

   • Open robot_car.ino in Arduino IDE
   • Select board: Tools → Board → ESP32 Arduino → Your ESP32 board
   • Select port: Tools → Port → (your ESP32 port)
   • Click Upload button
   • Wait for "Done uploading" message

3. Verify Upload

   • Open Serial Monitor (Tools → Serial Monitor)
   • Set baud rate to 115200
   • You should see initialization messages

3. Bluetooth Pairing

1. Enable Bluetooth on your smartphone/tablet
2. Scan for devices - Look for "ESP32_RobotCar"
3. Pair - Default PIN is usually "1234" or "0000"
4. Verify connection - Device should show as "Connected"

4. Install Control App

Recommended Android apps:

• Arduino Bluetooth Controller (by Mightyohm)
• Bluetooth RC Controller (by SimpleSoft)

See TESTING.md for detailed app configuration and button mapping.

5. Test the Car

1. Start with wheels off ground (safety first!)
2. Test basic movements: Forward (F), Backward (B), Left (L), Right (R)
3. Test speed control: Set speed to 20% (2), then try movements
4. Test on ground at low speed, then gradually increase

See TESTING.md for comprehensive testing procedures.

Command Reference

Movement Commands

Command	Function	Description
F	Forward	Both sides move forward
B	Backward	Both sides move backward
L	Turn Left	Right forward, left backward (spin left)
R	Turn Right	Left forward, right backward (spin right)
G	Forward Left	Right full speed, left reduced (diagonal)
1	Forward Right	Left full speed, right reduced (diagonal)
H	Back Left	Right backward full, left backward reduced
J	Back Right	Left backward full, right backward reduced
S	Stop	Stop all motors

Speed Control Commands

Command	Speed	PWM Value
0	0%	0
2	20%	51
3	30%	77
4	40%	102
5	50%	128 (default)
6	60%	153
7	70%	179
8	80%	204
9	90%	230
q	100%	255

Note: Speed 10% (command '1') conflicts with Forward Right movement. In current implementation, '1' triggers Forward Right. To achieve 10% speed, use speed 0% and gradually increase, or modify the code.

Special Commands

Command	Function	Description
D	Stop All	Emergency stop - stops motors and resets speed to default

File Structure

Robo car racing/
├── README.md           # This file - project overview and quick start
├── CONNECTIONS.md      # Detailed wiring diagram and connections
├── TESTING.md          # Comprehensive testing guide and troubleshooting
└── robot_car.ino       # Main Arduino code for ESP32

Technical Specifications

Hardware

• Microcontroller: ESP32 (240 MHz dual-core, WiFi/Bluetooth)
• Bluetooth Module: HC-06 (Classic Bluetooth, 9600 baud)
• Motor Drivers: BTS7960 (43A peak, H-bridge)
• Motors: 12V DC Gear Motors, 500 RPM
• PWM Frequency: 1000 Hz
• PWM Resolution: 8-bit (0-255)

Software

• Platform: Arduino IDE with ESP32 support
• Bluetooth Library: BluetoothSerial (built-in)
• Communication: Serial over Bluetooth (9600 baud)
• Command Protocol: Single ASCII character commands

Safety Warnings

⚠️ CRITICAL SAFETY INFORMATION

1. Power Supply Isolation

   • ESP32 and motors use separate power supplies
   • Never connect motor power (12V) directly to ESP32
   • Always use common ground connection

2. Current Requirements

   • Motors can draw 2-5A each at full load
   • Ensure battery pack can supply sufficient current
   • Use appropriate wire gauge for motor connections (18-20 AWG)

3. Testing Safety

   • Always test with wheels off ground first
   • Start with low speeds
   • Keep hands away from moving parts
   • Have emergency stop ready (D command)

4. Battery Safety

   • Use appropriate battery type (LiPo, NiMH, etc.)
   • Monitor battery voltage - don't over-discharge
   • Use proper battery protection circuits if needed
   • Charge batteries in safe location

5. Electrical Safety

   • Disconnect power before making wiring changes
   • Check for short circuits before powering on
   • Use proper insulation on all connections
   • Ensure no loose wires

Troubleshooting

Common issues and solutions:

Motors Not Moving

• Check 12V battery connection and charge
• Verify BTS7960 enable pins (L_EN, R_EN) are HIGH
• Check motor connections to M+ and M- terminals
• Verify common ground connection

Bluetooth Not Connecting

• Check HC-06 VCC is 3.3V (not 5V)
• Verify TXD/RXD connections (crossed: TX→RX, RX→TX)
• Try different pairing codes: "1234", "0000"
• Ensure device is within range (10 meters)

Wrong Motor Direction

• Swap M+ and M- connections on affected driver
• Or modify code to reverse direction logic

ESP32 Resets/Crashes

• Check power supply quality and current capacity
• Verify no short circuits
• Check for overheating

For detailed troubleshooting, see TESTING.md.

Customization

Adjust Default Speed

In robot_car.ino, modify:

int currentSpeed = 128;  // Change this value (0-255)

Adjust PWM Frequency

In robot_car.ino, modify:

#define PWM_FREQUENCY  1000  // Change frequency in Hz

Adjust Diagonal Movement Speed Ratio

In diagonal movement functions, modify the speed reduction:

int leftSpeed = currentSpeed / 2;  // Change /2 to /3, /4, etc.

Change Bluetooth Device Name

In robot_car.ino, modify:

SerialBT.begin("ESP32_RobotCar");  // Change device name

Project Status

✅ Hardware connections documented
✅ Arduino code implemented
✅ Testing procedures documented
✅ Command protocol defined
✅ Safety guidelines provided

Future Enhancements

Possible improvements:

• Add obstacle avoidance sensors
• Implement speed ramping for smoother acceleration
• Add battery voltage monitoring
• Implement PID control for precise movement
• Add LED indicators for status
• Create custom mobile app
• Add IMU for orientation control
• Implement autonomous navigation modes

License

This project is provided as-is for educational and hobby purposes.

Support

For issues or questions:

1. Review CONNECTIONS.md for wiring issues
2. Review TESTING.md for testing and troubleshooting
3. Check Serial Monitor output for error messages
4. Verify all connections match the documentation

Acknowledgments

• ESP32 Arduino Core developers
• BTS7960 motor driver documentation
• HC-06 Bluetooth module community

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Happy Building! 🚗💨

Remember: Safety first, test thoroughly, and have fun!