Thanks mrburnette.
It will take me a bit to do the background research to follow your post 100%.
My brother, a software engineer, also recommended either a Netduino or Raspberry Pi.
Cozir makes an integrated all in one Humidity/Temp/VNIR CO2 sensor that would be perfect. I need to find out what kind of device would be controlled by it to allow changes in ventilation of excess CO2 from the chamber.