Can You Recommend a CO2 sensor for the Raspberry Pi3?

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

mp2100 — Sat, 29 Sep 2018 01:48:08 GMT

I think it is important to understand why they want to measure CO2. I see sensors that measure the "eCO2", equivalent CO2. That measures something else (hydrogen) and extrapolates an equivalent CO2 from people's lungs. That's fine if the school wants to quantify the CO2 that the students are exhaling. But what if they want to know how much CO2 is being exhausted by a furnace or a chemical reaction in class? Then you'd use NDIR that Mark discusses.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

Former Member — Fri, 28 Sep 2018 19:44:40 GMT

I'll start out by saying I work for a company that sells some of the CO2 sensors below. I know this post is 6 months old, but I thought I could add some information not mentioned here.

CO2 sensors can be broadly broken into 2 camps: non-dispersive infrared (NDIR) and electrochemical (EC). If you breath on them, both will measure a change in CO2, but there are differences.

NDIR sensors include SenseAir, GSS, Teleaire by Amphenol, Winsen, Figaro (new), and others. They tend to be faster, last longer, and are more accurate. Price $85 and up. They will last a decade or more. NDIR uses light to measure the wavelength of the CO2 molecule. These are used in almost every commercial-grade CO2 transmitter for HVAC, to measure plant and animal respiration, or any application that depends on fast response (some like the GSS SprintIR make up to 20 readings per second!). Included in this list is the GSS COZIR, which uses an LED lamp instead of infrared to save power. Very cool tech, but it costs a few dollars more.

EC sensors like the older Figaro line or the mg-811 tend to be smaller, cheaper, slower, and have a shorter shelf life. Price $10 and up. They measure changes in a chemical reaction inside the sensor. The chemicals inside have a shelf life, anywhere from 1-3 years. Also, because these rely on chemistry, they tend to take a few minutes to see a change in CO2 levels. However, because of their low price, they tend to be popular in consumer products and for use by hobbyists.

If I was going to hook a CO2 sensor up just to show changes in indoor CO2 (for example, good vs. bad IAQ) any EC sensor will work. If I needed more accurate measurements (like changes from 400ppm to 500ppm) and ease of integration I'd look at a COZIR. If I needed complete control, analog or I2C output, high accuracy and proven technology, the SenseAir K30 would be a top contender.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

dougw — Sun, 04 Mar 2018 01:55:29 GMT

I've tried both the AenseAir and Amphenol sensors. I like them both, although the Amphenol device I tried was easier to use because it came with an arduino already programmed.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

beacon_dave — Sun, 04 Mar 2018 00:12:19 GMT

Tom Igoe's 'Making Things Talk' book uses the Hanwei mg-811 CO2 sensor for one of the projects.

A similar looking one with an interface is listed here:

https://sandboxelectronics.com/?product=mg-811-co2-gas-sensor-module

May be of interest.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

koudelad — Sat, 03 Mar 2018 20:43:56 GMT

Hello, have a look at my similar earlier discussion. CO2 sensor recommendation

SenseAir, Amphenol and GasSensing offer true CO2 sensors, but they have its price corresponding to the technology used.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

beacon_dave — Sat, 03 Mar 2018 20:38:52 GMT

Perhaps take a look at the Senseair S8 C02 sensor

https://senseair.com/products/size-counts/s8-lp/

which dougw used in his Safe and Sound design challenge ?

Safe and Sound - Environmental Factors - GAS Sensors - blog 16

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

michaelkellett — Sat, 03 Mar 2018 18:06:49 GMT

The OP should beware that these (Adafruit and Sparkfun parts) are not really CO2 sensors, being affected by many other things as well.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

ralphjy — Sat, 03 Mar 2018 17:57:41 GMT

Just as an alternative, I've used this Sparkfun breakout which is essentially the same as the Adafruit part that Gene mentioned https://www.sparkfun.com/products/14193.

Very simple to use. Communicates via I2C and can be temperature compensated using an optional thermistor.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

michaelwylie — Fri, 02 Mar 2018 23:22:26 GMT

I've used this sensor:

https://www.gassensing.co.uk/products/high-speed-sensors/sprintir-co2-sensor/

It has a digital interface and is easy to use. It's not cheap, but they may be able to get a sample since it's for education.

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

rscasny — Fri, 02 Mar 2018 23:02:48 GMT

Thanks Gene

RE: Can You Recommend a CO2 sensor for the Raspberry Pi3?

genebren — Fri, 02 Mar 2018 22:41:23 GMT

Randall,

I have no experience with this sensor, but it does seem to be about the least expensive and it should connect easily to an Ri3. (note it measures eCO2 (equivalent calculated carbon-dioxide) concentration within a range of 400 to 8192 parts per million (ppm)

https://www.adafruit.com/product/3566?gclid=Cj0KCQiAieTUBRCaARIsAHeLDCTXQpDyBEFpBVsdW-xjVaEfLGPx-i06IZl5nreizq-u-znIZjAs…

Gene