AirGradient Forum

Air Gradient Pro - CO2 below 400ppm

Components
#1

Hi all - my first post to the forum since buying an AirGradient Pro and 3 of the basic boards.

I have a few questions and notes;

  1. My CO2 sensor doesn’t seem to be very reliable. If I open the window and place the unit on the windowsill I’d expect the unit to self-calibrate back to 420 (or at least a baseline of 400). Instead, it’s been down to 114 and recently risen (in the space of around 20 seconds) to 205 (at the time of writing this).
    I’ve left it there for a few hours on a stable power supply with nothing else plugged in on that socket and have avoided moving it as much as possible.

  2. I’ve tried using the “Request CO2 calibration” check box on the app, and I assumed that it would be advisable to place the unit in the fresh air whilst this was carried out - it doesn’t appear to be doing anything.

  3. Is there a way of manually telling the device that it’s outside, and to calibrate itself to a baseline of 400?

  4. Is there a timeframe for calibration (do I need to leave this outside under a cover for 24 hours to get this calibration to work)

Notes: I even tried unplugging the device for a few hours to see if any cached errors might have been causing issues - after powering back up - same issues as before…

UK based - fairly cold at the moment

*No LEDs installed. *

*Sensor information still has 'current boot count: ’ (as in there is no data next to it in the AirGradient App
Calibration Request in Progress is under it - has been there for I think 3 days since I found the box to tick to request it…

#2

It looks like your sensor is not calibrated. The CO2 calibration from the dashboard is not yet implemented for the DIY monitors and thus it is not working.

There are two options.

a) you let it run for about a week and then the automatic baseline calibration will kick in. Make sure that within this week it has been exposed to ambient CO2 levels for at least 30 minutes.

b) you can flash some code to force a manual calibration and then flash the AirGradient code back

CO2 Calibration Requested not working for DIY Pro
Abnormally low CO2 readings
#3

Two things:

  1. How do I flash it manually?

  2. An entire week for a baseline is too long, I’d suggest taking that down to a maximum of three days. Can you explain the rationale behind a 1 week period? Is the device really logging an entire weeks worth of data to work out a base point?

How to make CO2 Sensor remain accurate Indoors?
#4

Does it have to be an entire week without a reboot \ power failure? Or would a power failure restart the count?

#5

I think reboots do not pose a problem but try to keep it connected as much as possible.

#6

If you pull the CAL pin low for between 4 and 8 seconds it puts the sensor into calibration mode assuming 400ppm CO2. See https://rmtplusstoragesenseair.blob.core.windows.net/docs/publicerat/PSP107.pdf for the pinout and more on the background calibration process.

#7

I have run into same problem - I tried to click recalibrate co2 sensor in dashboard manually on my airgradient one kit, but it also seems it does not do anything… Is it still not implemented for diy kits (those without soldering)?

#8

Hi @pitris90! Is this a new device? How long has it been online so far?

#9

Yes, new device, but i switched abc to period of 1 day and still i see no readings (or maybe zero and negative, appears offline in the dashboard) when i open window and vent my room. At the start when i first plugged it in, i saw more believeble values like when i vented, it measured lowest around 450.
I think i have it online from Sunday, but ill double check.

#10

@Altair_AirGradient So it has been running now surely for one week at least, but still it shows no readings when I open window and vent out… And clicking recalibrate device does not seem to do anything…

#11

Hi @pitris90,

Could you reach out to our support team (support@airgradient.com) and share the serial number of your device?

I will take a look at this for you.