https://youtu.be/hSYCt7LrYxQ Video instructivo /*MQ2 sensor with Arduino. * https://srituhobby.com */ # include <LiquidCrystal_I2C.h> LiquidCrystal_I2C lcd ( 0x27 , 16 , 2 ) ; # define LED 2 # define Buzzer 3 # define Sensor A1 void setup ( ) { Serial . begin ( 9200 ) ; lcd . init ( ) ; lcd . backlight ( ) ; pinMode ( LED , OUTPUT ) ; pinMode ( Buzzer , OUTPUT ) ; } void loop ( ) { int value = analogRead ( Sensor ) ; lcd . setCursor ( 0 , 0 ) ; lcd . print ( "Value :" ) ; lcd . print ( value ) ; lcd . print ( " " ) ; if ( value > 400 ) { digitalWrite ( LED , HIGH ) ; digitalWrite ( Buzzer , HIGH ) ; lcd . setCursor ( 0 , 1 ) ; lcd . print ( "GAS Detected!" ) ; } else { digitalWrite ( LED , LOW ) ; digitalWrite ( Buzzer , LOW ) ; lcd . setCursor ( 0 , 1 ) ; lcd . print ( " " ) ; } }