#include <DHT.h>

#define DHTPIN 4
#define DHTTYPE DHT22
#define MQ135_PIN 34
#define BUZZER 15

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
  pinMode(BUZZER, OUTPUT);
}

void loop() {

  int airValue = analogRead(MQ135_PIN);
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  String status;

  // Air Quality + Buzzer Logic
  if (airValue < 1000) {
    status = "Good";
    digitalWrite(BUZZER, LOW);   // OFF
  } 
  else if (airValue < 2000) {
    status = "Moderate";
    digitalWrite(BUZZER, LOW);   // OFF
  } 
  else {
    status = "Poor";
    digitalWrite(BUZZER, HIGH);  // ON (Alert)
  }

  Serial.println("------ Air Quality Monitoring ------");
  Serial.print("Air Value: ");
  Serial.println(airValue);

  Serial.print("Air Quality: ");
  Serial.println(status);

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

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

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

  delay(2000);
}