Remote Air Quality Monitoring IoT

This IoT project monitors air quality, temperature, and humidity in real-time, sending data to the Blynk app. It uses an ESP32 microcontroller, a DHT11 sensor for temperature and humidity, and an MQ135 sensor for air quality (CO2 levels). The system also sends alerts when parameters exceed defined thresholds. The MQ135 sensor requires 24-hour warm up period for accurate CO2 readings.

Features

• Monitors temperature, humidity, and air quality (CO2 levels).
• Sends data to the Blynk app for real-time monitoring.
• Alerts when:
  • Temperature > 100°C
  • Humidity > 85%
  • Air Quality (CO2) > 1000 PPM
• Uses MQ135 for air quality (requires calibration) and DHT11 for temperature and humidity.
• Supports ESP32 and WiFi.

Hardware Setup

DHT11 (Temperature & Humidity)

• VCC to 3.3V
• GND to GND
• Data Pin to GPIO 4

MQ135 (Air Quality)

• VCC to 5V
• GND to GND
• Analog Output (AOUT) to GPIO 34

ESP32

• Use an ESP32 DevKit or compatible board.

Software Setup

1. Install Libraries:

   • Install Blynk, DHT, and MQ135 libraries via Arduino IDE.

2. Create Blynk Project:

   • Create a new project in the Blynk app for ESP32.
   • Add Value Display widgets for temperature (V0), humidity (V1), and air quality (V2).
   • Get the auth token from Blynk and add it to the code.

3. Upload Code:

   • Replace WiFi credentials and Blynk AUTH Token in the code.
   • Open the Arduino IDE and select the correct ESP32 board and COM port.
   • Upload the code to ESP32.

Calibration

After setting up the system, ensure the MQ135 sensor is given at least 24 hours to warm up for reliable readings. During this period, the code checks whether the sensor is still in the warm-up stage and displays a message in the Serial Monitor.

Alerts Thresholds

• Temperature > 100°C
• Humidity > 85%
• Air Quality (CO2) > 1000 PPM The alerts will display notifications on the Blynk app, notifying the user of any critical environmental changes.

Timers

A Blynk timer is used to send sensor data to the Blynk app every 60 seconds (timer.setInterval(60000L, sendSensorData);).

Example Output (Serial Monitor)

When the system is running, the serial monitor will display the following information:

Sensor Readings:
Temperature: 25.3 °C
Humidity: 55.6 %
Air Quality: 300
Corrected CO2 PPM: 400.56

Troubleshooting

• DHT11 issues: Ensure correct wiring and if readings are consistently NaN, reset the DHT sensor in the code using dht.begin();.
• MQ135 calibration: Wait for the 24-hour warm-up period and ensure proper calibration and that it's not exposed to any significant air contaminants for accurate CO2 PPM readings.
• Blynk app: Check WiFi and auth token if no data is received.

License

This project is open-source under LICENSE. Modify and use it as needed.