CO2 sensor similar to Ruuvi?


#1

Hi,

Does anyone here know a CO2 (or other air quality) sensor that’s similarly open and easy to use as the Ruuvi?

I’d love to add that to my Ruuvi-based monitoring. Unfortunately, I’m very much a software person, so any solution that requires hand-crafting electronics won’t work for me.

Might also be a nice feature for a Ruuvi 2.0.

Best,
David


#2

Hello,

CO2 sensors generally consume a lot of power and are therefore poorly suited for battery-operated devices.
Let us know if you find a good sensor or a product, we’re absolutely interested in CO2 measurements :smile:


#3

@DCBB We might see Bosch BME680 on our upcoming products:

https://www.bosch-sensortec.com/bst/products/all_products/bme680


#4

Wow, that one would be great! Thanks for sharing this.


#5

Looks like a good article that makes mention of the MG811 CO2 detector:

Configure and read out the Raspberry Pi gas sensor (MQ-X)


#6

Nordic Thingy has some sort of a gas sensor on board:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.rds%2Fdita%2Frds%2Fdesigns%2Fthingy%2Fhw_description%2Fenv_sensors.html

How does that compare to the BME680 for example?


#7

The gas sensor (CCS811) seems to have CO2 equivalent measurement, while BME680 does not have CO2. Thank you for linking the sensor, we’ll look into it


#8

As I understand, Nordic Thingy uses CCS811 which contains also BME680.


#9

Where did you see that CCS811 measures CO2?
According documentation it detects VOC gases, not CO2


#10

Datasheet, http://ams.com/eng/content/download/951091/2269479/471718 . It’s strange that CO2 is not mentioned as one of the main features :thinking: Maybe it’s because the sensor reports CO2 equivalent value which includes other greenhouse gases rather than actual CO2?


#11

OK
Algorithm result. The most significant 2 bytes contain a
ppm estimate of the equivalent CO2 (eCO2) level, and
the next two bytes contain a ppb estimate of the total
VOC level.


#12

I found this
"It’s important to recognize that the CCS811 cannot measure CO2 and that the “equivalent CO2” being reported by the CCS811 has nothing to do with actual CO2 present in the area"
from, here


#13

Excellent explanation on eCO2, thanks for the link!


#14

Don’t bother with the CCS811 for CO2 measurements - it’s “CO2 equivalent” readings do not correlate with those obtained from CO2 sensors.

BME680 gives a ballpark number for IAQ and I would leave it at that. See page 9 of the following for practical uses: https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME680-DS001-00.pdf

Enabling BME680’s gas sensor sucks power and you’ll be lucky to get battery life longer than 12 months. Additionally, enabling the gas sensor will warm up the interior of the Ruuvi tag puck and distort temperature and humidity readings

BME680 does not like small particulates - filtering has to be good or else the sensor cavity gets contaminated with particulate junk and readings diverge drastically. (i.e. do not walk around Beijing with your BME680 on bad pollution days)

From my experience, the BME680 (like the CCS811) adds nice bells and whistles that are good for marketing but provide false security because they do not accurately represent the datums that they are measuring.

We’ve evaluated the BME680 and similar sensors and came to the conclusion that MAYBE, just MAYBE, in 2 or 3 years, low-powered gas sensors will be at the maturation stage that they can be used as reliable sensors in mobile/portable applications.

And yes, I’m ready for the backlash of comments regarding my critique. Sitting on my workbench shelf is a row of sensors that have been under test for months. Trying to evaluate the trade-offs between measurement quality, power consumption and cost. Low cost sensors look great on marketing brochures but quality of measurement (QoM) is poor and my database of recorded measurements does not correlate with what marketing brochures promote. I trust what I measure rather than what I am told.

The BME280 is a good sensor at a reasonable price so stick with it!


#15

@WizardAtLarge Those are all good points. Thanks for sharing this :+1:


#16

Being a geek, I counted sensors in test
==> 46 sensors currently under test with 2 to 3 of each model
==> Two new sensors added to test: Ruuvi tags. Ruuvi tag PCBAs removed from their enclosures. Both reading within one degree C and 2% humidity
==> 3rd Ruuvi tag on workbench on top of Dev Shield and Nordic Dev Board. Temp on this tag is 3C higher (T) and 10% lower (RH) than the Ruuvi tags under test. Readings construed by the NRF52-DK radiating heat from underneath
==> Sensors removed from testing include: CCS811, DS18B20, TMP102. Note: these were removed from test for one or more of the following: inaccurate readings, repeatability, power consumption, operating voltage range and/or reliability


#17

@WizardAtLarge BTW, have you tried Sensirion SGPC3 and IDT ZMOD4410?

We’re working with a new product and are considering to have a VOC sensor in it.