#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 = 5;  
int yellowLED = 4;
int greenLED = 3; 
int buzzer = 6;  
int sensorThresholdLow = 100;   // Batas rendah gas bocor (100 ppm)
int sensorThresholdHigh = 200;  // Batas tinggi gas bocor (200 ppm)
int sensorThresholdMid = 400;   // Batas kebocoran gas menengah (400 ppm)
int flameSensorPin = 7;  // Pin untuk sensor api (flame sensor)

void setup() {
  pinMode(Sensor_gas, INPUT);
  pinMode(redLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(flameSensorPin, INPUT);  // Mengatur pin sensor api sebagai input
  
  lcd.backlight();
  lcd.display();
  lcd.begin(16,2);
  lcd.clear();
  
  Serial.begin(9600);
}

void loop() {
  int analogSensor = analogRead(Sensor_gas);  // Membaca sensor gas analog
  int ppm = map(analogSensor, 0, 1023, 0, 500);  // Mapping nilai sensor ke ppm gas
  
  int flameDetected = digitalRead(flameSensorPin);  // Membaca status sensor api

  // Menampilkan kondisi sensor gas pada LCD
  lcd.setCursor(0, 0);
  lcd.print("Kondisi Ruangan:");
  lcd.setCursor(0, 1);
  
  // Cek apakah ada api
  if (flameDetected == HIGH) {
    lcd.print("API DETECTED!");  
    digitalWrite(redLED, HIGH);  // LED merah menyala
    digitalWrite(yellowLED, LOW); // LED kuning mati
    digitalWrite(greenLED, LOW);  // LED hijau mati
    tone(buzzer, 750);  // Bunyi buzzer terus menerus
  }
  else {
    // Gas di atas 400 ppm
    if (ppm > sensorThresholdMid) {
      lcd.print("Gas bocor! (>400ppm)");  
      digitalWrite(redLED, HIGH);
      digitalWrite(yellowLED, LOW);
      digitalWrite(greenLED, LOW);
      tone(buzzer, 750);  // Bunyi buzzer terus menerus
    }
    // Gas antara 201-400 ppm
    else if (ppm > sensorThresholdHigh) {
      lcd.print("Gas bocor! (201-400ppm)");  
      digitalWrite(redLED, LOW);
      digitalWrite(yellowLED, HIGH);
      digitalWrite(greenLED, LOW);
      tone(buzzer, 750, 500);  // Bunyi buzzer lebih cepat (500ms interval)
    }
    // Gas antara 100-200 ppm
    else if (ppm > sensorThresholdLow) {
      lcd.print("Gas bocor! (100-200ppm)");
      digitalWrite(redLED, LOW);
      digitalWrite(yellowLED, LOW);
      digitalWrite(greenLED, HIGH);
      tone(buzzer, 750, 1000);  // Bunyi buzzer sedikit lebih cepat (1 detik interval)
    }
    // Gas aman
    else {
      lcd.print("Gas aman (0-100ppm)");
      digitalWrite(redLED, LOW);
      digitalWrite(yellowLED, LOW);
      digitalWrite(greenLED, HIGH);
      noTone(buzzer);  // Tidak ada bunyi buzzer
    }
  }
  
  delay(1000);  // Jeda 1 detik sebelum pembacaan berikutnya
}