CO2 Monitor Mobile App

A React Native Expo application for monitoring CO2 levels from ESP32 sensors via MQTT.

Features

• Real-time CO2 monitoring from dual sensors
• MQTT connectivity to ESP32 devices
• Push notifications for high CO2 levels
• Historical data visualization
• Configurable thresholds and settings
• Dark/light theme support

Development Setup

Prerequisites

1. Install Node.js (v18 or later)
2. Install Expo CLI: npm install -g @expo/cli
3. Install EAS CLI: npm install -g eas-cli

Getting Started

1. Clone the repository

2. Install dependencies:

   npm install

3. Start the development server:

   npm run dev

Building for Mobile Devices

Since this app uses native dependencies (MQTT, notifications), you need to create a development build:

Step 1: Setup EAS Build

1. Create an Expo account at https://expo.dev

2. Login to EAS CLI:

   eas login

3. Configure your project:

   eas build:configure

Step 2: Create Development Build

For Android:

eas build --platform android --profile development

For iOS:

eas build --platform ios --profile development

Step 3: Install Development Build

1. Download the APK/IPA from the EAS build dashboard
2. Install on your device
3. Run the development server:

   npm run dev

4. Scan the QR code with your development build

Step 4: Create Production Build

For Android APK:

eas build --platform android --profile preview

For iOS TestFlight:

eas build --platform ios --profile preview

For Production:

eas build --platform all --profile production

Configuration

MQTT Settings

The app connects to HiveMQ Cloud with these settings (configured in contexts/CO2Context.tsx):

• Host: 495e05bee6cb40cd97eeb41fc597850e.s1.eu.hivemq.cloud
• Port: 8884 (WebSocket Secure)
• Username: esp32-device1
• Password: Password@2025
• Topic: sensors/esp32-co2-01/data

ESP32 Compatibility

This app is designed to work with ESP32 devices running the provided CO2 monitoring firmware that publishes data in this JSON format:

{
  "device": "esp32-co2-01",
  "co2_1": 450,
  "co2_2": 460,
  "timestamp": 1640995200,
  "wifi_rssi": -45,
  "heap_free": 234567
}

Deployment Options

Option 1: EAS Build (Recommended)

• Builds in the cloud
• Supports both iOS and Android
• Automatic code signing
• Easy distribution

Option 2: Local Build

# Android
npx expo run:android

# iOS (macOS only)
npx expo run:ios

Option 3: Expo Application Services

Use EAS Submit to distribute to app stores:

eas submit --platform android
eas submit --platform ios

Troubleshooting

Common Issues

1. MQTT Connection Failed

   • Check internet connection
   • Verify HiveMQ Cloud credentials
   • Ensure ESP32 is publishing data

2. Notifications Not Working

   • Grant notification permissions
   • Check notification settings in app
   • Verify device notification settings

3. Build Errors

   • Clear cache: npx expo install --fix
   • Reset Metro: npx expo start --clear
   • Check EAS build logs

Development Tips

• Use npx expo doctor to check for common issues
• Monitor logs with npx expo logs
• Test on physical devices for best results
• Use EAS Build for production deployments

License

MIT License - see LICENSE file for details