Smart College Bell Automation System

A complete offline smart bell automation system using ESP32 and Flutter mobile app. The system allows colleges to automate bell schedules without requiring internet connectivity.

Features

ESP32 Firmware

• ✅ Offline operation with DS3231 RTC module
• ✅ WiFi Access Point mode (no internet required)
• ✅ Flash memory storage for schedules
• ✅ Relay control for bell activation
• ✅ Manual override button
• ✅ LED status indicator
• ✅ RESTful API endpoints
• ✅ Automatic schedule triggering

Flutter Mobile App

• ✅ Home screen with current time and next schedule
• ✅ Schedule management (CRUD operations)
• ✅ Time synchronization with ESP32
• ✅ Manual bell control
• ✅ Connection status monitoring
• ✅ Material Design 3 UI

Hardware Requirements

ESP32 Components

• ESP32 Development Board
• DS3231 RTC Module
• 5V Relay Module
• Push Button (for manual override)
• LED Indicator
• College Bell/Buzzer
• Jumper Wires

Wiring Diagram

ESP32 Pin    →    Component
GPIO25       →    Relay IN
GPIO2        →    LED Indicator
GPIO34       →    Manual Button (with pull-up)
GPIO21       →    DS3231 SDA
GPIO22       →    DS3231 SCL
GND          →    All GND connections
5V           →    Relay VCC, DS3231 VCC

Installation

ESP32 Firmware Setup

1. Install PlatformIO IDE or CLI
2. Navigate to the firmware directory:

   cd esp32_firmware

3. Connect ESP32 via USB
4. Upload firmware:

   pio run --target upload

5. Monitor serial output:

   pio device monitor

Flutter App Setup

1. Ensure Flutter is installed (3.x or higher)
2. Install dependencies:

   flutter pub get

3. Run the app:

   flutter run

Usage Guide

Initial Setup

1. Power on ESP32

   • ESP32 creates WiFi hotspot: SmartBell_AP
   • Password: smartbell123

2. Connect Mobile Device

   • Connect phone to SmartBell_AP WiFi network
   • Open the Smart Bell app

3. Sync Time

   • Go to Settings tab
   • Tap "Sync Time to ESP32"
   • This sets the RTC to current phone time

Managing Schedules

1. Add Schedule

   • Go to Schedules tab
   • Tap the + (Add) button
   • Fill in:
     • Label (e.g., "Morning Bell", "Lunch Break")
     • Day of week
     • Time (HH:MM)
     • Duration (seconds)
   • Tap Save

2. Delete Schedule

   • Go to Schedules tab
   • Tap the delete icon on any schedule
   • Confirm deletion

3. View Schedules

   • Schedules are grouped by day
   • Shows time, label, and duration
   • Next scheduled bell shown on Home screen

Manual Control

1. From App

   • Go to Home screen
   • Tap "Ring Bell Now" button
   • Bell rings for 5 seconds

2. From ESP32

   • Press the manual button on ESP32
   • Bell rings for 5 seconds

Time Synchronization

• Initial sync required after setup
• Sync again if time drifts
• RTC maintains time even when powered off (coin battery)

API Documentation

Base URL

http://192.168.4.1

Endpoints

Get Schedules

GET /get_schedules
Response: Array of schedule objects

Add Schedule

POST /add_schedule
Body: {
  "hour": 9,
  "minute": 0,
  "duration": 5,
  "dayOfWeek": 1,
  "label": "Morning Bell",
  "enabled": true
}
Response: {"success": true, "id": 1}

Delete Schedule

POST /delete_schedule
Body: {"id": 1}
Response: {"success": true}

Ring Bell Now

POST /ring_now
Body: {"duration": 5}
Response: {"success": true}

Sync Time

POST /time_sync
Body: {
  "year": 2025,
  "month": 10,
  "day": 3,
  "hour": 14,
  "minute": 30,
  "second": 0
}
Response: {"success": true}

Get Current Time

GET /get_time
Response: {
  "year": 2025,
  "month": 10,
  "day": 3,
  "hour": 14,
  "minute": 30,
  "second": 15,
  "dayOfWeek": 1
}

Technical Details

ESP32 Firmware

• Framework: Arduino (PlatformIO)
• Libraries:
  • WiFi.h - WiFi AP mode
  • WebServer.h - HTTP server
  • Preferences.h - Flash storage
  • RTClib.h - DS3231 RTC
  • ArduinoJson.h - JSON handling
• Storage: Up to 20 schedules in flash memory
• RTC: I2C communication with DS3231

Flutter App

• Framework: Flutter 3.x
• State Management: Provider
• HTTP Client: http package
• Date Formatting: intl package
• Architecture: Provider pattern with separate models, services, and screens

Troubleshooting

ESP32 Not Connecting

• Ensure ESP32 is powered on
• Check if WiFi AP SmartBell_AP is visible
• Verify password: smartbell123
• Restart ESP32 if needed

Time Not Syncing

• Check WiFi connection
• Ensure app has proper permissions
• Verify ESP32 is responding to API calls
• Check RTC battery if time resets

Bell Not Ringing

• Check relay connections
• Verify relay is getting power
• Test relay with manual button
• Check bell/buzzer power supply

Schedules Not Triggering

• Ensure time is synced correctly
• Verify schedule day matches RTC day
• Check if schedule is enabled
• Confirm schedule time format (24-hour)

Security Notes

• System designed for local network only
• No authentication implemented (school premises only)
• WiFi password should be changed for security
• Not exposed to internet by design

Future Enhancements

• Multiple bell patterns
• Holiday schedule management
• Schedule import/export
• Bell volume control
• Weekly schedule templates
• Notification logs
• Web dashboard

License

This project is provided as-is for educational and commercial use.

Support

For issues and questions:

1. Check the troubleshooting section
2. Review API documentation
3. Verify hardware connections
4. Check serial monitor output from ESP32