// Include the library for LCD with I2C interface
#include <LiquidCrystal_I2C.h>
// Include the library for the DHT sensor
#include <DHT.h>

// Initialize the LCD (I2C address: 0x27, dimensions: 16 columns and 2 rows)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Define the pin and sensor type for the DHT22
#define DHTPIN 2         // Digital pin connected to the DHT22 sensor
#define DHTTYPE DHT22    // Define sensor type as DHT22
DHT dht(DHTPIN, DHTTYPE); // Create a DHT object

// Define variables for storing sensor values
float humidity;    
float temperature;
int buzzer = 12;         // Buzzer connected to digital pin 12

// Setup runs once at startup
void setup() {
  lcd.init();             // Initialize the LCD
  lcd.backlight();        // Turn on LCD backlight
  dht.begin();            // Start the DHT sensor
  pinMode(buzzer, OUTPUT); // Set buzzer pin as output

  Serial.begin(9600);     // Initialize Serial Monitor
  Serial.println("Temperature & Humidity Monitoring System Initialized");

  // Optional indicator LEDs for status display
  pinMode(9, OUTPUT);  // Red LED
  pinMode(10, OUTPUT); // Yellow LED
  pinMode(11, OUTPUT); // Green LED
}

// Main loop runs continuously
void loop() {
  delay(2000);  // Sensor reading delay (2 seconds)

  // Read humidity and temperature from DHT sensor
  humidity = dht.readHumidity();
  temperature = dht.readTemperature();

  // Print readings to Serial Monitor
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.print(" %\t");

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

  // Condition 1: High temperature and high humidity
  if (humidity >= 70.0 && temperature >= 30.0) {
    digitalWrite(9, HIGH);   // Red LED ON
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    
    lcd.setCursor(0, 0);
    lcd.print("  Too Warm!     ");
    lcd.setCursor(0, 1);
    lcd.print("  Cool Down!    ");
    
    for (int i = 0; i < 2; i++) {
      digitalWrite(buzzer, HIGH); tone(buzzer, 900, 100); delay(400);
      digitalWrite(buzzer, LOW);  tone(buzzer, 900, 100); delay(400);
    }
  }

  // Condition 2: Normal temperature and humidity
  else if (humidity < 70.0 && temperature < 30.0) {
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, HIGH);  // Green LED ON

    lcd.setCursor(0, 0);
    lcd.print("Temp & Humidity ");
    lcd.setCursor(0, 1);
    lcd.print("are Normal       ");

    digitalWrite(buzzer, LOW);
  }

  // Condition 3: High temperature, normal humidity
  else if (humidity < 70.0 && temperature >= 30.0) {
    digitalWrite(9, LOW);
    digitalWrite(10, HIGH);  // Yellow LED ON
    digitalWrite(11, LOW);

    lcd.setCursor(0, 0);
    lcd.print("Warning!         ");
    lcd.setCursor(0, 1);
    lcd.print("Temp too High!   ");

    for (int i = 0; i < 1; i++) {
      digitalWrite(buzzer, HIGH); tone(buzzer, 500, 400); delay(400);
      digitalWrite(buzzer, LOW);  tone(buzzer, 500, 400); delay(400);
    }
  }

  // Condition 4: High humidity, normal temperature
  else if (humidity >= 70.0 && temperature < 30.0) {
    digitalWrite(9, LOW);
    digitalWrite(10, HIGH);  // Yellow LED ON
    digitalWrite(11, LOW);

    lcd.setCursor(0, 0);
    lcd.print("Warning!         ");
    lcd.setCursor(0, 1);
    lcd.print("Humidity High!   ");

    for (int i = 0; i < 1; i++) {
      digitalWrite(buzzer, HIGH); tone(buzzer, 500, 400); delay(400);
      digitalWrite(buzzer, LOW);  tone(buzzer, 500, 400); delay(400);
    }
  }
}