This proves your library is working.
Would you like a sample Proteus .DSN file with MQ135 already wired to an Arduino? mq135 gas sensor library for proteus download upd work
In Proteus, simulating this sensor allows you to test your , PIC , or 8051 code against varying gas concentrations without risking hardware damage. How to Download the MQ135 Library for Proteus This proves your library is working