#define MQ2pin 8

int sensorValue;  //variable to store sensor value

#include <LiquidCrystal_I2C.h>
#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4                // variable for reading the pin status
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void setup() {
	lcd.init();
  lcd.backlight();

	Serial.begin(9600); // sets the serial port to 9600
	Serial.println("MQ2 warming up");
	  lcd.setCursor(1, 0);
    lcd.print("MQ2 warming up");
	delay(500); // allow the MQ2 to warm up
	lcd.clear();
	delay(500);
}

void loop() {
	sensorValue = digitalRead(MQ2pin); // read digital output pin
	Serial.print("Digital Output: ");
  //lcd.setCursor(1, 0);
  //lcd.print("DigitOut: ");
	Serial.print(sensorValue);
	//lcd.setCursor(1, 0);
  //lcd.print(sensorValue);
	
	// Determine the status
	if (sensorValue) {
		Serial.println("  |  Smoke: -");
	} else {
		Serial.println("  |  Smoke: Detected!");
		lcd.setCursor(1, 1);
    lcd.print("Smoke");
	}
	
	delay(2000); // wait 2s for next reading
}