ESP32 Obstacle Avoidance Bot with Web Control

A smart obstacle avoidance robot with dual operation modes: autonomous navigation and manual web-based control via WiFi.

Features

• 🤖 Auto Mode: Autonomous obstacle avoidance using ultrasonic and IR sensors
• 🎮 Manual Mode: Web-based remote control from any smartphone/tablet
• 📱 Responsive Web UI: Touch-optimized interface for mobile devices
• ⚡ PWM Speed Control: Adjustable motor speed (0-255)
• 📊 Real-time Sensor Data: Live sensor readings on web interface
• 🔄 Mode Switching: Seamless switching between Auto and Manual modes

Hardware Requirements

Components

• ESP32 Development Board
• HC-SR04 Ultrasonic Sensor (1x)
• IR Obstacle Sensor Modules (2x - front and back)
• L298N Motor Driver (or similar with EN pins)
• DC Motors (2x)
• Robot Chassis
• Power Supply (suitable for motors and ESP32)

Pin Configuration

WiFi Access Point

SSID: ObstacleBot
Password: robot123

Setup Instructions

1. Hardware Assembly

1. Mount all sensors and motors on the robot chassis
2. Connect components according to the pin configuration table above
3. Ensure proper power distribution to motors and ESP32
4. Double-check all connections before powering on

2. Software Upload

1. Install Arduino IDE and ESP32 board support
2. Install required libraries (already included in ESP32 core):
   • WiFi.h
   • WebServer.h
3. Open obstacle_avoidance_bot.ino
4. Select your ESP32 board from Tools > Board
5. Select the correct COM port
6. Upload the sketch to your ESP32

3. First Run

1. Power on the robot
2. Open Serial Monitor (115200 baud) to see startup messages
3. Note the Access Point IP address (typically 192.168.4.1)

Usage Guide

Connecting to the Bot

1. Connect to WiFi

   • On your phone/tablet, go to WiFi settings
   • Connect to network: ObstacleBot
   • Enter password: robot123

2. Open Web Interface

   • Open browser and navigate to: http://192.168.4.1
   • The control panel will load automatically

Operating Modes

Auto Mode (Default)

• Bot autonomously avoids obstacles
• Uses ultrasonic sensor for distance detection
• IR sensors for close-range detection
• Automatically navigates around obstacles

Manual Mode

• Full manual control via web interface
• Directional buttons: Forward, Backward, Left, Right
• Hold buttons to move, release to stop
• Real-time control with immediate response

Speed Control

• Adjust speed slider (0-255)
• Changes apply immediately to both Auto and Manual modes
• Default speed: 200
• Lower speeds for precision, higher for faster movement

Sensor Monitoring

• Distance: Ultrasonic sensor reading (cm)
• Front IR: Obstacle detection status
• Back IR: Rear obstacle detection status
• Current Speed: Active motor speed value

Web Interface Features

Responsive Design

• Optimized for mobile phones and tablets
• Touch-friendly button sizes
• Prevents accidental page scrolling
• Works on all modern browsers

Control Layout

      ▲ (Forward)
  ◄   ■   ► (Left, Stop, Right)
      ▼ (Backward)

Real-time Updates

• Sensor data refreshes every 500ms
• Immediate command execution
• Visual feedback for mode changes

Troubleshooting

Cannot Connect to WiFi

• Ensure ESP32 is powered on
• Check Serial Monitor for AP IP address
• Try forgetting network and reconnecting
• Verify password is correct: robot123

Motors Not Responding

• Check motor driver connections
• Verify EN pins (18, 19) are connected
• Test in Manual mode first
• Check power supply to motors

Sensors Not Reading

• Verify sensor pin connections
• Check sensor power (VCC/GND)
• View sensor data in web interface
• Check Serial Monitor for debug output

Web Page Not Loading

• Verify WiFi connection
• Use correct IP: 192.168.4.1
• Try different browser
• Check Serial Monitor for errors

Customization

Change WiFi Credentials

Edit in the sketch:

const char* AP_SSID = "ObstacleBot";
const char* AP_PASSWORD = "robot123";

Adjust Pin Assignments

Modify pin definitions at the top of the sketch to match your wiring.

Tune Obstacle Avoidance

const int DISTANCE_THRESHOLD_CM = 20;  // Obstacle detection distance
const unsigned long BACKUP_TIME_MS = 400;  // Backup duration
const unsigned long TURN_TIME_MS = 450;    // Turn duration

Change IR Sensor Logic

If your IR sensors are active HIGH:

const bool FRONT_IR_ACTIVE_LOW = false;
const bool BACK_IR_ACTIVE_LOW = false;

Safety Notes

• Always test in a safe, open area first
• Keep emergency stop accessible (Manual mode > Stop button)
• Monitor battery levels to prevent motor driver damage
• Start with lower speeds when testing
• Ensure proper motor driver heat dissipation

Version History

• v1.0 - Initial release with Auto/Manual modes and web control

License

Open source - modify and use as needed for your projects!

Support

For issues or questions, check:

• Serial Monitor debug output (115200 baud)
• Web interface sensor readings
• Pin connection verification

Enjoy your obstacle avoidance bot! 🤖