AirGradient Open Air Returning high temprature with ESPHome

#1

This morning my Open Air starting reporting outside temps over 6500 degrees C. Both sensors are reporting 6553.2 C. I’m using ESPHome 12.7. It happens when it’s below freezing. I’m assuming it a heater of some sort. I use the temp to measure the temperature outside but that obviously won’t work as things stand. Is there anything to do about it?

#2

Use the forum search, you can find previous topics like Air Gradient Outdoor temperature tolerances - #8 by diffair :slight_smile:

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#3

The short version is: this was a bug in ESPHome, and a future release will have the fix.

Also, your ESPHome version is probably 2023.12.7, not just 12.7. The current release (as of yesterday) is 2023.12.8 but it does not contain the fix for this problem.

#4

Thank you for this! I had done some searching but only found calibration questions. I’ll just wait until Feb for a fix. I’m glad it’s not a hardware issue.

#5

Yesterday I put in a temporary fix into my ESPHome config, so if you are using my branch, you can get the fix there. I was using the old temp/humidity compensation algorithm, so working right now to update it to the latest one.

If you are running your own config, this is what you can put under the PMS5003T sensor section:

    temperature:
      name: "Temperature"
      id: temp
      filters:
          # https://forum.airgradient.com/t/outdoor-temperature-and-humidity-reading-correction/1544/19
        - lambda: !lambda |-
            // Remove line with (x > 6000) once the negative number issue fix is merged in https://github.com/esphome/issues/issues/3814
            if (x > 6000) return ((x - 6553.6) * 1.327) - 6.738;
            if (x < 10.0) return (x * 1.327) - 6.738;
            return (x * 1.181) - 5.113;
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#6

Also as an FYI… 6500 C is nearly double the melting point of tungsten, so it’s rather unlikely that any sort of heater in the AirGradient Open Air could produce that temperature :slight_smile:

#7

At least you would probably need a slightly stronger power supply :slight_smile:

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#8

I was wondering if I had discovered a new type of fusion. It was exciting for a little while!

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#9

This is great. I’ve put it in my code and it appears to be working great. Thank you!!!

#10

I checked with my contact at ESPHome and they put the fix into the next release milestone so if all testing goes well it should be out in the next update probably sometime this week.

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#11

ESPHome 2023.12.9 has been released and contains the fix for the PMS5003T temperature readings.