//Made by ALFY HUGH 
//Date: 18/2/2024

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
#define Buzzer 2
#define Sensor A0

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  pinMode(Buzzer, OUTPUT);
  Serial.print(" GAS DETECTION SYSTEM READY ");
  Serial.println("              ");
}

void loop() {
  int value = analogRead(Sensor); //Reads the sensor and gives an OUTPUT
  lcd.setCursor(0, 0);
  lcd.print("Value :");
  lcd.print(value);
  lcd.print("  ");
  delay(750);

  if (value > 375) {      //You can change the threshold value however you like.

    digitalWrite(Buzzer, HIGH);
    lcd.setCursor(0, 1);
    lcd.print("GAS Detected!");
    Serial.println(" GAS DETECTED! ");

  } else {

    digitalWrite(Buzzer, LOW);
    lcd.setCursor(0, 1);
    lcd.print("             ");
  }
}