by Added support for the Parallax CO2 sensor board, you must connect TP1 to a spare analog pin to use, and it will give a consistent, but not that accurate reading on Co2 in parts per million.
Added support for the Parallax CO2 sensor board, you must connect TP1 to a spare analog pin to use, and it will give a consistent, but not that accurate reading on Co2 in parts per million.