Arduino-Based Air Quality Monitoring System

This project monitors air quality using an MQ-135 gas sensor and an LM35 temperature sensor, controls an air purifier, and sends data to ThingSpeak using an ESP8266 Wi-Fi module. An I2C LCD display shows real-time values.

Arduino Uno

ESP8266 Wi-Fi Module

MQ-135 Gas Sensor

LM35 Temperature Sensor

Servo Motor (for air purifier fan control)

I2C LCD Display (16x2)

Buzzer (for alerts)

Resistors & Jumper Wires

Breadboard

1.1 Power Connections

1. Connect 5V from Arduino to VCC of:
2. ESP8266
3. MQ-135 Gas Sensor
4. LM35 Temperature Sensor
5. I2C LCD
6. Connect GND from Arduino to GND of all components.

1.2 Sensor Connections

1. MQ-135 Gas Sensor:
2. A0 → Arduino A0
3. LM35 Temperature Sensor:
4. VOUT → Arduino A1

1.3 Air Purifier Motor

1. Signal Pin → Arduino D5
2. VCC → 5V
3. GND → GND

1.4 I2C LCD Display

1. SDA → Arduino A4
2. SCL → Arduino A5

1.5 ESP8266 Wi-Fi Module

1. TX → Arduino RX (D0)
2. RX → Arduino TX (D1)
3. CH_PD → 3.3V

1. Open Arduino IDE and install the following libraries if not already installed:
2. Adafruit_LiquidCrystal
3. DHT (for temperature and humidity sensor)
4. Copy and upload the provided Arduino code.

ESP8266 Setup: Connects to Wi-Fi and ThingSpeak.

Sensor Readings:

1. Reads gas concentration from MQ-135.
2. Reads temperature from LM35.
3. Converts gas sensor values to AQI (Air Quality Index).

Air Purifier Control:

1. Turns ON when AQI is above 150.
2. Turns OFF when AQI is safe.

LCD Display:

1. Shows temperature, gas levels, and AQI.
2. Displays motor status (ON/OFF).

ThingSpeak Data Upload:

1. Sends real-time sensor data every 15 seconds.

https://thingspeak.mathworks.com/channels/2887824/

1. Power the circuit using USB or an external power source.
2. Check the LCD display for sensor values.
3. Observe the motor (fan) status based on AQI.
4. Open ThingSpeak to verify data updates.

Click here to get Tinkercad Simulation link

AirQualitymonitor - Tinkercad