O2 sensor to Arduino Uno

Hi all,

I am looking to make a home warning system, since I'm going to be installing a pellet stove inside my new garage. I wish to have my Arduino Uno read data from O2 sensor, located inside the smokestack and if the ppm numbers cross a certain threshold, the Uno would let me know if the burning is incomplete. A complete combustion results in just CO2 and H2O, no O2, right? A steady readout on my computer would also be good. Could anyone give advice on what kind of sensor I should use and how I would connect it to the Uno? Could I use a car lambda sensor somehow? Or would it be more efficient to use a CO2 sensor in this case?

no O2, right?

Wrong. Complete combustion will just leave excess O2. But if the smokestack is working properly, it doesn't matter what goes up the chimney. The problem occurs if the chimney is blocked somehow and combustion products are emitted into the garage. IMO you need a carbon monoxide (CO - not CO2) detector in the garage. You must also ensure that there is sufficient air flow in the garage to provide sufficient O2 to the stove to minimize the possibility of CO production. You must also check to find out what local building codes apply to the installation of a stove.