#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>


#define DHTPIN 7     
#define DHTTYPE DHT22  
#define MQ135PIN A0  


LiquidCrystal_I2C lcd(0x27, 16, 2); 
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600); 

  dht.begin();


  lcd.begin(16, 2); 
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Air Quality Ready");
  delay(2000);
  lcd.clear();
}

void loop() {
  
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  
  int airQuality = analogRead(MQ135PIN);

  
  int pm25 = random(10, 100);

  
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print("C");

  lcd.setCursor(0, 1);
  lcd.print("Hum: ");
  lcd.print(humidity);
  lcd.print("%");
  delay(2000);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("CO2: ");
  lcd.print(airQuality);
  lcd.print(" ppm");

  lcd.setCursor(0, 1);
  lcd.print("PM2.5: ");
  lcd.print(pm25);
  lcd.print(" ug/m3");
  delay(2000);

  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" C");

  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.println(" %");

  Serial.print("Air Quality (CO2): ");
  Serial.print(airQuality);
  Serial.println(" ppm");

  Serial.print("PM2.5: ");
  Serial.print(pm25);
  Serial.println(" ug/m3");

  Serial.println("----------------------");
}