Mamtaz Alam
Published © GPL3+

IoT Based Air Quality Index Monitoring with MQ135 & ESP8266

We will monitor the air quality index in PPM using MQ135 Air Quality Sensor & ESP8266. The logged data will ca be observed in Thingspeak.

IntermediateFull instructions provided3 hours250
IoT Based Air Quality Index Monitoring with MQ135 & ESP8266

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Schematics

Circuit Diagram & Connections

Code

Air Quality Index Monitoring Code

C/C++
Using Arduino
#include <ESP8266WiFi.h>
#include <SPI.h>
#include <Wire.h>
#include "MQ135.h"
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128    // OLED display width, in pixels
#define SCREEN_HEIGHT 64    // OLED display height, in pixels
#define OLED_RESET -1       // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

String apiKey = "********"; // Enter your Write API key from ThingSpeak
const char *ssid = "**********";     // replace with your wifi ssid and wpa2 key
const char *pass = "**********";
const char* server = "api.thingspeak.com";

WiFiClient client;


void setup()
{
  Serial.begin(115200);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); //initialize with the I2C addr 0x3C (128x64)
  display.clearDisplay();
  delay(10);

  Serial.println("Connecting to ");
  Serial.println(ssid);
  
  display.clearDisplay();
  display.setCursor(0,0);  
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.println("Connecting to ");
  display.setTextSize(2);
  display.print(ssid);
  display.display();
  
  WiFi.begin(ssid, pass);

  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }
    Serial.println("");
    Serial.println("WiFi connected");
    
    display.clearDisplay();
    display.setCursor(0,0);  
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.print("WiFi connected");
    display.display();
    delay(4000);
}


  void loop()
  {
    MQ135 gasSensor = MQ135(A0);
    float air_quality = gasSensor.getPPM();
    Serial.print("Air Quality: ");  
    Serial.print(air_quality);
    Serial.println("  PPM");   
    Serial.println();

    display.clearDisplay();
    display.setCursor(0,0);  //oled display
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.println("Air Quality Index");
    
  
    display.setCursor(0,20);  //oled display
    display.setTextSize(2);
    display.setTextColor(WHITE);
    display.print(air_quality);
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.println(" PPM");
    display.display();


    if (client.connect(server, 80)) // "184.106.153.149" or api.thingspeak.com
  {
    String postStr = apiKey;
    postStr += "&field1=";
    postStr += String(air_quality);
    postStr += "r\n";
    
    client.print("POST /update HTTP/1.1\n");
    client.print("Host: api.thingspeak.com\n");
    client.print("Connection: close\n");
    client.print("X-THINGSPEAKAPIKEY: " + apiKey + "\n");
    client.print("Content-Type: application/x-www-form-urlencoded\n");
    client.print("Content-Length: ");
    client.print(postStr.length());
    client.print("\n\n");
    client.print(postStr);
    
    Serial.println("Data Send to Thingspeak");
  }
    client.stop();
    Serial.println("Waiting...");

    delay(2000);      // thingspeak needs minimum 15 sec delay between updates.
}

Credits

Mamtaz Alam

Mamtaz Alam

1 project • 0 followers
I am passionate about Latest Electronics Innovations & advancement in the field of Arduino, Internet of Things & Power Electronics Design.

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