The official description of the ccs811 "Ultra-low power digital gas sensor for monitoring indoor air quality". Something not all sellers put in their description

Yes the CO2 reading is an estimate or relative to VOC reading nonetheless still a useful indication and it’s better in my opinion than the BME680. Other than the SHT35 with a permeable filter there are currently no sensors suitable for outside use. Humidity and atmospheric components will destroy most devices given time.

Yes Adafruit release their libraries for general use, I have never used Adafruit products, but sometimes like the bme280 sensors they use a different device address and so the library needs different settings to get things working, but this rare. Some really low cost devices maybe out of specification from China, that’s the risk, but generally if they are the difference is marginal for most applications.

@@G6EJD I see, thank you for the clarification!

Sơn Nguyễn Minh, the device is calibrated at the factory. The only way you can calibrate by varying the reading value is to use an external reference like any other calibration method. It’s more of a qualitative measurement giving degrees of concentration

Yes, it's actually the device temperature reading when the sample was taken, it has to heat up the internal sensor to take a reading and in that regard is not that useful, it's certainly not room temperature.

Ah that explains it, thanks.

None are very accurate more a relative reading, if you want a reliable high accuracy and repeatable sensor they start at around £50/$75 and they all take some time to read. The sensor featured here is an estimated CO2 reading based on the readings of other gases, a mix that would probably occur in most situations.

There's a sort of spot-price on AliExpress, I got mine from WorldChips and paid £4.13 including postage, but I see today it is £6.35. For the more expensive one, I paid £11.97, but now £11.54 but it does have an on-board NTC which gives a slightly more accurate temperature response.

You could, but you have to adjust the registers to do that and as they don’t publish an error graph by how much? No idea so maybe what’s the point, just use as is.

Which pins you use depends on the board type, are you using an ESP32 or ESP8266 and what is the board name? If an ESP8266 nodemcu type then the correct pins are 4 and 5, let me know

@@G6EJD a "Wemos D1 Mini" like i wrote above, an ESP8266. The Sensor breakoutboard also looks exactly like your purple one. In your picture at 3:20, the middle-one is exactly my setup.

Kartoffelsnack, so what is not happening are you getting any values on the serial port? Most problems will be wiring based assuming the sensor is ok.

I haven't tried it yet, because i don't know how to change the code to fit the pins on the 'd1 mini'.

If your using the Wemos D1 Mini then connect the sensor to D1 and D1 as labelled and shown in the centre diagram.

Have you go the right I2C connections, have you tried an I2C scanner, check the data sheet for it's I2C address it should be found. You probably do not have the correct i2C pins connected.

Check the data sheet it says: CCS811 measurements to output a TVOC value or equivalent CO2 (eCO2) levels, where the main cause of VOCs is from humans. So yes.

No that’s right, this is why the bme680 is better as it adds temperature, pressure a f humidity to VOC detection. The CCS811 requires a burn-in time of 48 hours and a run-in of 20 minutes (you must allow 20 minutes for the sensor to warm up and output valid data). Note: Temperature compensation from an attached NTC Thermistor is no longer supported on the CCS811.

@@G6EJD thanks

Morten mo, using a fan will give you false results due to wind chill etc.

@@G6EJD but when there is no air movement near sensor ... are co2 results ok then?

Morten mo, you will always have natural air movement to give you a reading and the gases don’t tend to be in pockets of air and are naturally dispersed. You can use a fan but don’t expect accurate results

The LCD library is inbuilt so I suggest trying out one of the examples then adding the driver and lcd.print statements to my code.

@@G6EJD Do I just need to substitute an serial.print for an lcd.print?

Михаил the other way around. Every time you want to display on the LCD do a lcd.print

Does not measure O2, use something like this: www.seeedstudio.com/Grove-Oxygen-Sensor-ME2-O2-f20.html

@@G6EJD thanks ! that's what I fear too expensive and not available in my country :(

Check out: Grove O2 sensor LuminOx sensor R17/R21/R22 sensor Figaro (such as K50) UK City/Citicel sensor (4OXV/7OXV) SenSore sensors Possibly even a car lambda sensor such as Bosch LSU 4.9

Car lambda sensor might the be lowest cost sensor if you can get a data sheet for one.

I can’t find any low cost, easy to use sensors for O2

12K in clean air

@@G6EJD is this confirm or not??

Actually I am searching a lot on Google but couldn't find any value of Ro/Rs for the Mics 6814 sensor for finding the No2 ??..I am stuck at this point..

You can look up the data sheet and it gives the ranges there down to 0ppm, I just did and that’s the value it says.

@@G6EJD 12 K is for which sensor??

I had the same experience as Graham Wise. I tried two different CCS811 sensors with an ESP8266 and even moved to an Arduino. After a couple of days the VOC / CO2 readings were completed useless. One reset and it start working again.... What about you David Bird, have you run it for some days? Did you experiment any drift? BTW, thanks for all the great videos!

I think by the time VOC rises above the background / normal values CO2 levels becomes largely irrelevant as the toxic air is driven by the VOC content. So-far I've found it tracks the CO2 levels quite well.

Well I have only been running it after being woke up from sleep then I take 4-readings as the first 2 are usually 0’s as the sensor heats then I get a stable and sensible reading so I take the fourth. I could use the nINT output to wait for a valid reading too, but I find the simple approach is working ok for me. I have also noted that it’s very sensitive to power supply variations and takes quite a lot of power. I’m not aware of any endemic issues with the sensor either, so I suspect it’s down to application.

These things can't distinguish CO2 from VOCs, they're sensitive to a wide range of gasses with different sensitivity levels. The eCO2 reading they provide is only valid if there is ONLY CO2 present. CO2 is typically one of the gasses that metal oxides sensors are *least* sensitive to, so basically the presence of any VOCs makes the eCO2 reading totally invalid, because it will appear much higher since the sensor is more sensitive to VOCs. @Graham Wise is correct, these things are not useful for measuring CO2 indoors. You really consider the eVOC reading to be accurate either, it's really only good for deviations from baseline. Actual CO2 sensors are kind of expensive because of how they work, even the cheapest ones on Aliexpress are $25 or more.

There are a number of issues here, first I believe most implementations do not apply the device data sheet instructions for use such as modes and for establishing and updating the baseline and to be fair to the manufacturer they do clearly state the CO2 reading is ‘equivalent’ not actual and they don’t quote any accuracy figures so we have to determine that the device is a relative reading only, but for most most applications the device can be used successfully to determine if the atmosphere contains gases that are higher than the device baseline, it’s most definitely not an absolute measurement device. If the air is good the readings will be low if bad high, that’s probably all we need to know.

Yes and no, how would you say Command Control Communication and Information C3I in my world that’s C 3 I not C Cube I 😀

I think you should read the data sheet again, your wrong it measures Volatile Organic Compounds and estimates the Carbon-dioxide level NOT Carbon-monoxide. If you don’t agree please write and complain to the manufacturer that the lowest cost and power sensor on the market isn’t good enough and doesn’t measure CO2 and ask them what they are going to do about it.

He's somehow right, it seems that there are two versions sold: CO2: www.ebay.de/itm/CCS811-HDC1080-CO2-Carbon-Dioxide-VOCs-Air-Quality-Temperature-Humidity-Sensor-F/232747057091?hash=item3630ce3fc3:g:cv0AAOSw7I5a4Xqv:rk:9:pf:0 CO: www.ebay.de/itm/CJMCU-CCS811-811-Carbon-Monoxide-CO-Cov-Gas-Sensors-Air-Quality-Numerical/263548924643?hash=item3d5cbd72e3:g:R8sAAOSwlJlaqOA-:rk:8:pf:0