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

#define MQ2_ANA A1
#define MQ2_DIG 2
const int limit =400;


void setup() {

  // put your setup code here, to run once:
  Serial.begin(9600);
  lcd.begin(16,2);
  lcd.backlight();

  pinMode(MQ2_ANA, INPUT);
  pinMode(MQ2_DIG, INPUT);
  pinMode(5, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  
  Serial.print("Analog: ");
  Serial.println(analogRead(MQ2_ANA));
  Serial.print("Digital: ");
  Serial.println(digitalRead(MQ2_DIG));
  delay(1000);
  lcd.setCursor(0,0);
  lcd.print("Analog: ");
  lcd.println(analogRead(MQ2_ANA));
   lcd.setCursor(0,1);
  lcd.print("Digital: ");
  lcd.println(digitalRead(MQ2_DIG));
  delay(1000);
  lcd.clear();

  if(  (analogRead(MQ2_ANA))<limit){
  digitalWrite(4, HIGH);
  digitalWrite(3, LOW);


  }else{
    digitalWrite(3,HIGH);
    digitalWrite(4, LOW);
   
  }
}