#include <Wire.h> //library untuk komponen I2C
#include <LiquidCrystal_I2C.h> //Library untuk LCD Display I2C
LiquidCrystal_I2C lcd(0x27, 16, 2);

int mq2Pin = A0;      // Analog pin connected to MQ2 A0 output 
int redLed = 12;      // Digital pin connected to a red LED
int sensorThres = 90; // Threshold value for gas detection
int buzzer = 7;       //Pin buzzzer

void setup() {
  pinMode(mq2Pin, INPUT);     // Mendeklarasikan pin MQ2 sebagai input
  pinMode(redLed, OUTPUT);    // Mendeklarasikan pin LED sebagai output
  pinMode(buzzer, OUTPUT);    // Mendeklarasikan pin BUZZER sebagai ouput
  Serial.begin(9600);         
  lcd.init();  
  lcd.backlight();  
  lcd.setCursor(0, 0);
  lcd.print("KELOMPOK 5");
  lcd.setCursor(1, 1);
  lcd.print("GAS SENSOR");
  delay(1000);
  lcd.clear();
}

void loop() {
  delay(1000);
  int analogSensorValue = analogRead(mq2Pin); // Membaca value dari sensor MQ2
  digitalRead(buzzer);

  Serial.print("Output MQ-2: ");
  Serial.println(analogSensorValue); // Print sensor value to Serial Monitor

  // Check if the sensor value exceeds the threshold
  if (analogSensorValue > sensorThres) {
    digitalWrite(redLed, HIGH); // Nyalain LED
    digitalWrite(buzzer,HIGH); //Nyalain Buzzer
  } else {
    digitalWrite(redLed, LOW);  // Mematikan LED
    digitalWrite(buzzer,LOW); //Mematikan Buzzer
  }

  // Update LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("GAS: ");
  lcd.print(analogSensorValue); 

  lcd.setCursor(0, 1);
  if (analogSensorValue > sensorThres) {
    lcd.print("Status: Bahaya");
  } else {
    lcd.print("Status: Aman  ");
  }
}