Hi Suresh
Generally mems based gas sensors are metal oxide sensos which show response to
reducing or oxidising gases.Unfortunately CO2 cannot be detected by such
sensors.So I think one method to do a CO2 sensor would be to use IR absorption
spectra.One should fabricate a tunable optical filter (ppl have done that) and a
IR detector with  on chip spectrum analysing circuitry using mems
technology.There may be other simpler solutions but i am unaware of them.
abhijith

On Tue, 27 Sep 2005 Suresh Raja wrote :
>Hi All,
>
>Can any one tell me what are all the methods for developing a MEMS
>based Carbon dioxide sensor?