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Topic: Temp, Humidity CO2 sensor and library. (Read 50 times) previous topic - next topic

gaines

I was interested in this sensor so I contacted GSS which relayed my request to their North American partner, AirTest Technologies. I was very impressed with the quick response time and they promptly provided me with information on their products.

For my purposes, the Corzir-A (Ambient) with a range of 0-2000 ppm is perfect. It also has optional temperature and humidity sensors. The part number for that combination is COZIR-A-2000-X-H and I'm told it's $183.

How does that compare to other CO2 sensors? It's definitely more than I was hoping to spend, but at the same time it may be worth the price if it simplifies my project.

DirtGambit

Hi Gaines, I havent tested the cozir against any other Co2 sensor but it seems accurate enough, I usually calibrate via fresh air and that gives me a ball park figure for what Im using the sensor for, it certainly responds very well if the house has been empty all day and someone comes in it will pick up that very quickly. $183 is not a bad price, and its all in one, so no need for many libs, wires etc.

The only drawback from an arduino point of view is the sensor communicates through serial which makes the process a bit more difficult getting the data you want, it would have been nice to have a digital version, 3 pins and just asks the sensor for the values but this limits its application I suppose because GSS also supply a usb cable that fits directly to the sensor and can run via their software without the need for any dev board.

I do think its something GSS should consider, getting rid of the serial and going digital might lower the cost. Getting rid of streaming mode is another thing Id like to see, its a pain in the @$$. :)

Regards

robtillaart

Hi DirtGambit,

Can you determine the presence of someone with the sensor?  detecting an intruder? how fast?
Would be a nice new application !
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

DirtGambit

Oh yeah for sure as long as it wasnt really time critical, it stays between 390 - 420ppm (+-10ppm) all day, within 5 minutes of someone coming into the livingroom it will quite happily go up to 550ppm especially if you go near the sensor, I had some friends round one night, 4 people in a smallish living room, I was shocked to see 1500ppm on the graph.

A few years ago there was a study into co2 concentration in old schools, the average co2 during school time was > 2000ppm in some of them, in this case peaks were found at 3500ppm (I read a study once that had peaks of 4500ppm), a few schools had really good results but they were still > 1200ppm and had very good ventilation.

DirtGambit

robtillaart

5 minutes seems rather long, but in those 5 minutes it goes from ~400-550 so it rises ~30ppm/minute. That means that one could detect it within 60 seconds that the CO2 level has rissen, and if well positioned maybe within 30 seconds. WHat is the minimum time you can detect in your graphs? If it is within 1 minute it would be great (OK depends on size of the room etc.

Do you see the same change in temperature - gues not- and humidity - could be? Humans exhale water and CO2 (they are reverse trees :) so those two should change significantly from some average value.

Ideas pop in my mind, like counting people by means of their CO2 output. Fun!
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

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