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

#define DHTPIN 15
#define DHTTYPE DHT22
#define MQ2_PIN 34
#define LDR_PIN 35
#define BUZZER 26
#define LED 27

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

void setup() {
  Serial.begin(115200);

  dht.begin();
  lcd.init();
  lcd.backlight();

  pinMode(MQ2_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(LED, OUTPUT);

  lcd.setCursor(0, 0);
  lcd.print("Smart Factory");
  lcd.setCursor(0, 1);
  lcd.print("Monitoring...");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read sensors
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();
  int gas = analogRead(MQ2_PIN);
  int light = analogRead(LDR_PIN);

  // Print to Serial Monitor
  Serial.print("Temp: "); Serial.print(temp);
  Serial.print("C  Hum: "); Serial.print(hum);
  Serial.print("%  Gas: "); Serial.print(gas);
  Serial.print("  Light: "); Serial.println(light);

  // Display on LCD
  lcd.setCursor(0, 0);
  lcd.print("T:"); lcd.print(temp); lcd.print("C ");
  lcd.print("H:"); lcd.print(hum); lcd.print("%");

  lcd.setCursor(0, 1);
  lcd.print("G:"); lcd.print(gas);
  lcd.print(" L:"); lcd.print(light);

  // Alert system
  if (temp > 40 || gas > 1500) {
    digitalWrite(BUZZER, HIGH);
    digitalWrite(LED, HIGH);
  } else {
    digitalWrite(BUZZER, LOW);
    digitalWrite(LED, LOW);
  }

  delay(2000);
}