Instructables

How does one measure the level of carbon dioxide in the air?

I'm planning to see if more Carbon Dioxide in the air is good for plants, but to do this I need a way to measure (moderately accurate readings) of the concentration of Carbon Dioxide in the air. Money isn't too much of an issue, just not too much (over $100 is too much) but it needs to be quick and easy to use.

Ideas?


mark484302 years ago
If you want to stay under $100 (and you have some programming skills) you could start with an NDIR CO2 sensor and connect it to a PC with an Arduino board.
I found this:
http://www.woodrow.org/teachers/esi/1999/princeton/projects/c3_c4/Group4web.html
It's an overview of an experiment similar to the one you describe.  The author of this page mentions some kind of test kit for measuring CO2 concentration. 

This test may involve the use of lime water to trap CO2(gas) from an air sample and convert it to insoluble CaCO3(solid).  The actual quantities and concentrations of CO2 involved are small.  If the amount of lime in the water is also small, the reaction may produce a significant change in pH, which you can measure using an indicator.  That's just a guess.  I'm not actually sure how this trick is supposed to work.

More on lime water, and its reaction with CO2 can be found in the Wiki article on lime water:
http://en.wikipedia.org/wiki/Lime_water
Re-design4 years ago
CO2 meters aren't cheap.  The least expensive I could find was this one.  See if it would work for you. 

It may actually be a good choice since it works with a computer and is a data logger.
mathews4 years ago
There are a few pre-made probes that you can buy (one, two), however with no prices quoted, I'd assume that it might be costly.

Or as shown through links from the second you can produce your own, based on IR absorbtion of IR light. (Images in "produce", english in "own").

(Got to love Google Translate)