This code compatible with severals Arduino Board
Original Articles: https://hackaday.io/project/3475-sniffing-trinket/log/12363-mq135-arduino-library
MQ-135 Library: https://github.com/ckalpha/MQ135
Author: Damrongwit Nusuk
Email: jack@racksync.com
Visit Website: http://www.racksync.com
Website : http://www.racksync.com