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

#define DHT_PIN 15       // ESP32 pin GPIO1 connected to DHT22 sensor's data pin
#define TRIG_PIN 19     // ESP32 pin GPIO19 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN 18     // ESP32 pin GPIO18 connected to Ultrasonic Sensor's ECHO pin
#define LED_PIN 12      // ESP32 pin GPIO12 connected to LED's anode
#define BUZZER_PIN 14   // ESP32 pin GPIO14 connected to buzzer's positive pin

#define LCD_ADDRESS 0x27 // I2C address of the LCD display
#define LCD_COLUMNS 16   // Number of columns in your LCD
#define LCD_ROWS 2       // Number of rows in your LCD

LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_COLUMNS, LCD_ROWS); // Initialize the LCD object
DHT dht(DHT_PIN, DHT22); // Initialize DHT sensor object

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

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  // Initialize the LCD
  lcd.begin(LCD_COLUMNS, LCD_ROWS);
  lcd.backlight(); // Turn on the backlight (if available)
  lcd.clear();     // Clear the LCD screen
  lcd.setCursor(0, 0);
  lcd.print("Distance:");

  // Initialize DHT sensor
  dht.begin();
}

void loop() {
  // Ultrasonic sensor measurements
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  unsigned long duration = pulseIn(ECHO_PIN, HIGH);
  // Speed of sound is 343m/s or 0.0343cm/us
  float distance_cm = duration * 0.0343 / 2;

  // DHT sensor measurements
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Print the distance on LCD
  lcd.setCursor(0, 0);
  lcd.print("                "); // Clear the line
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance_cm);
  lcd.print(" cm");

  // Print DHT data on LCD
  lcd.setCursor(0, 1);
  lcd.print("Temp: ");
  lcd.print(temperature);

  // Print the distance and DHT data on serial monitor
  Serial.print("Distance: ");
  Serial.print(distance_cm);
  Serial.print(" cm, ");
  Serial.print("Temperature: ");
  Serial.print(temperature);
  // Turn on LED if distance is less than 100cm
  if (distance_cm < 100) {
    digitalWrite(LED_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH); // Turn on the buzzer
  } else {
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW); // Turn off the buzzer
  }

  // Display fire alert if temperature exceeds 45°C
  if (temperature >= 30.0) {
    lcd.setCursor(0, 1);
    lcd.print("Fire Alert!");
    delay(2000); // Delay for 2 seconds to display the fire alert message
  }

  delay(1000); // Delay for 1 second before next measurement
}