#include <Wire.h>;
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2); // Default address of most PCF8574 modules, change according
int seconds = 0;  
int Sensor_gas = A0;  
int redLED = 4;  
int greenLED = 3; 
int buzzer = 5;  
int sensorThreshold = 400; 

void setup() {
  // put your setup code here, to run once:
    pinMode(Sensor_gas, INPUT);
    pinMode(redLED, OUTPUT);
    pinMode(greenLED, OUTPUT);
    pinMode(buzzer, OUTPUT);
    lcd.backlight();
    lcd.display();
    lcd.begin(16,2);
    lcd.clear();
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int analogSensor = analogRead(Sensor_gas);
  if (analogSensor > sensorThreshold)
{
    lcd.setCursor(0, 0);
    lcd.print("Kondisi Ruangan:");
    lcd.setCursor(0, 1);
    lcd.print("GAS BOCOR!      ");
     digitalWrite(redLED, HIGH);
     digitalWrite(greenLED, LOW);
     tone(buzzer, 750, 1000);
   }
else // 
   {
    lcd.setCursor(0, 0);
    lcd.print("Kondisi Ruangan:");
    lcd.setCursor(0, 1);
    lcd.print("Gas aman       ");
     digitalWrite(redLED, LOW);
     digitalWrite(greenLED, HIGH);
     noTone(buzzer);
   }
   delay(1000);  // Jeda Waktu 1 detik u/ pembacaan berikutnya
}