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CCS811 - invalid values - very small changes pls help!
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CCS811 - invalid values - very small changes pls help!

by Glitch_69 on Tue Mar 13, 2018 3:38 pm

I have a CCS811, attached to RPi3. It seems on i2c bus, and I can run the test file from Adafruit. Everything works as expected, and as can be seen in the tutorial.
My issue is - after 48 hour burn in time, I have just a very small variance to 400 value. In a room, I have eCO2 400-420 ppm, measuring with an other device, it is abt 1200 ppm
So the value is not realistic, and almost the same,
here are some measures: https://thingspeak.com/channels/78908
All help / advise is more than welcome to fix this!!
thx in advance

Glitch_69
 
Posts: 5
Joined: Fri Sep 18, 2015 3:00 pm

Re: CCS811 - invalid values - very small changes pls help!

by franklin97355 on Tue Mar 13, 2018 5:22 pm

Can you post your connections and the code you are using to test this?

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Location: Lacomb, OR.

Re: CCS811 - invalid values - very small changes pls help!

by Glitch_69 on Wed Mar 14, 2018 4:00 am

thx for your reply!
here is my code - simple one, im just started to learn...
Code: Select all | TOGGLE FULL SIZE
#       reading ccs811

ccs =  Adafruit_CCS811()

while not ccs.available():
        pass
temp = ccs.calculateTemperature()
ccs.tempOffset = temp - 20.0


if ccs.available():
        temp = ccs.calculateTemperature()
if not ccs.readData():
#       print "CO2: ", ccs.geteCO2(), "ppm, TVOC: ", ccs.getTVOC(), " temp: ", temp
        co2 = ccs.geteCO2()
        co2ok = str(co2)
        tvoc = ccs.getTVOC()
        tvocok = str(tvoc)
else:
         print "ERROR!"

this is from the adafruit example file -- and i import:
from Adafruit_CCS811 import Adafruit_CCS811
and i send co2,tvoc to thinggspeak

in regards of connection - followed the example on the link above, and the sensor is available in i2c bus, also pin wake is connected to low.
Everything works, but the data seems to be not valid, as you can see in the thingspeak chartshttps://thingspeak.com/channels/78908 - inside of the room is about 400 - 420ppm, withs is
too low.
What did I miss --- i guess, others, following the example, have the same values - -when I check tutorials, or youtube videos, more or less they
show the same 400ppm at the beginning.....
May ask you to explain, what does burn in mean? I powered up the sensor, ans run this code for two days - maybe it is a problem, and the burn in process means something else?
thx for advance!

Glitch_69
 
Posts: 5
Joined: Fri Sep 18, 2015 3:00 pm

Re: CCS811 - invalid values - very small changes pls help!

by Glitch_69 on Wed Mar 14, 2018 7:35 am

i just used a gas lighter for a few sec, abt 5cm from the sensor - and it is reacted, but the value, 805 eCO2, and 62 TVOC are too low - i guess
Attachments
gas_lighter.JPG
gas_lighter.JPG (40.52 KiB) Viewed 96 times

Glitch_69
 
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Joined: Fri Sep 18, 2015 3:00 pm

Re: CCS811 - invalid values - very small changes pls help!

by Glitch_69 on Sat Mar 17, 2018 5:12 pm

is there someone, who would share the measured values with me pls? Im really curious , others measure similar eCO2/TVOC as me - mostly 400-420 eCO2.
These are not correct, im sure, controlled with a handheld device, the CO2 is abt 1700 ppm.
I do not understand this - em I the only one, who has this issue?????

Glitch_69
 
Posts: 5
Joined: Fri Sep 18, 2015 3:00 pm

Please be positive and constructive with your questions and comments.