Air Quality Monitor

A professional-grade Air Quality Monitor based on the ESP32-S3, featuring high-precision sensors, a built-in web-manager for configuration, and MQTT integration for Smart Home systems.

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🚀 Features

• Dual-Sensor Monitoring:

  • CO₂, Temperature, and Humidity: via Sensirion SCD30 (NDIR technology).
  • PM1.0, PM2.5, PM10: via Plantower PMS5003 (Laser scattering).

• Advanced Display UI (ST7735):

  • **Real-time CO₂ Graph: 30-minute visual history with auto-scaling.
  • **Persistent Clock: Smart RTC logic that keeps showing time even if Wi-Fi connection is lost (after initial sync).
  • **Smooth Progress Bar: Visual indicator of data refresh cycles.
  • **System Diagnostics: Detailed splash screen showing sensor and network health on boot.

• Web-Based Settings Manager:

  • **On-the-fly Config: Change Wi-Fi, MQTT details, GMT offset, and DST settings via browser.
  • **Built-in WiFi Scanner: Easily find and connect to networks through the web UI.

• MQTT Integration: Stream real-time data to Home Assistant, OpenHAB, or Node-RED in JSON format with status indicators (M:OK / M:ERR).

• Smart Connectivity:

  • **Multi-WiFi Support: Remembers and automatically connects to up to 5 saved networks.
  • **Fallback AP Mode: Automatically enters Access Point mode if no saved Wi-Fi is available.

• Reliability:

  • **Non-Volatile Memory: All settings are securely saved in ESP32 Flash (Preferences).
  • **Internal RTC Persistence: Enhanced time-keeping stability without constant internet polling.

🛠 Hardware Components

Component	Purpose	Interface
ESP32-S3	Main Controller	-
Sensirion SCD30	CO₂, Temp, Humidity	I2C (Pins 12, 13)
Plantower PMS5003	Dust Particles (PM)	UART (Pins 10, 11)
ST7735 1.8" LCD	Visual Dashboard	SPI (Pins 1-6)

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📊 Interpretation Levels

The device uses universal color-coding for both the Web UI and the TFT Display:

Level	CO₂ (ppm)	PM2.5 (µg/m³)	Color
Good	< 800	0 - 12	🟢 Green
Fair	800 - 1200	13 - 35	🟡 Orange
Poor	1200 - 2000	36 - 55	🔴 Red
Bad	> 2000	> 55	🟤 Dark Red

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⚙️ Configuration & Setup

1. Upload:

   • Download the AirMonitor_v2.0 directory.
   • Open AirMonitor_v2.0.ino in your Arduino IDE.
   • Note: Ensure all project files (.ino, .h, .cpp) remain in this folder for the project to compile correctly.
   • Select ESP32-S3 Dev Module and flash the sketch to your device.

2. First Boot:

   • The device will create a temporary Wi-Fi network: AIR-SCAN-CONFIG (Password: 12345678).

3. Web Portal:

   • Connect your phone or PC to this network and navigate to http://192.168.4.1 in your browser.

4. Settings:

   • Scan for your local Wi-Fi network and enter the credentials.
   • Enter your MQTT Broker details (optional).
   • Click Save & Restart.

5. Operation:

   • After rebooting, the device will display its new local IP address on the screen.
   • Enter this IP in your browser to access the real-time monitoring dashboard.

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📡 MQTT Payload Format

The device publishes a JSON string to the topic air/status every 10 seconds:

{
  "co2": 650,
  "pm1": 5,
  "pm25": 12,
  "pm10": 15,
  "t": 24.5,
  "h": 45
}

🔌 Wiring Diagram

📝 License

This project is open-source and available under the MIT License. Feel free to modify and improve!