# CO2 sensor



## naoki (Jan 13, 2016)

This is a little esoteric, but I found an affordable CO2 sensor here, so I thought that some people may be interested in it:

http://www.ebay.com/itm/Honeywell-A...219209?hash=item58d174de09:g:edMAAOSwo0JWJmDk

This is an older model, so the price is really slashed (they accepted my 10% lower offer). The price is much cheaper than the cheapest CO2 sensor alone (e.g. K-30 costs around $100, and MG811 around $50)!

People are wondering what this is to do with orchids. It could be just used as a CO2 meter. Or my plan is to use it as a CO2 logger and eventually as the CO2 controller (for CO2 injection). It can be used in 2 ranges: 0-2000ppm or 0-10000ppm. The sensor will output the CO2 ppm in an analog form (4-20mA or 0-20mA). I haven't figured out the details, but I'm going to connect it to Arduino to make a controller. I just started to learn about Arduino (and ESP8266), so I might be wrong. In this case, well, I got a cheap CO2 meter.

This model comes with Nondispersed Infrared (NDIR) sensor. See wikipedia for the 2 types of sensors. I don't know the details, but my impression is that NDIR is better than the cheaper chemical sensors (e.g. MG811)?? Polyantha or ChrisFL may know more about this.

It probably can be used to get some measurement of photosynthetic rate. Here is a link to Polyantha's interesting post:
http://www.slippertalk.com/forum/showthread.php?t=32896


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## SlipperFan (Jan 14, 2016)

Naoki, somehow there were two threads exactly the same. I deleted one.


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## abax (Jan 14, 2016)

Maybe I needed two threads! I didn't understand a word
of it. The scientific technical talk goes right over my
head...Whoosh.


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## naoki (Jan 15, 2016)

Thank you, Dot. I wonder why.

Sorry Angela, it's safe to ignore.  Only a couple geeks would be excited about this great deal!


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## cnycharles (Jan 15, 2016)

abax said:


> Maybe I needed two threads! I didn't understand a word
> of it. The scientific technical talk goes right over my
> head...Whoosh.




 two threads = 'double talk' heh



Elmer Nj


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## abax (Jan 15, 2016)

naoki, I never ignore your posts! I might actually learn
a thing or two if I concentrate to understand.


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