Modify BME280 humidity value

  • Platform information:
    • Hardware: Raspberry Pi 3b+ Processor: BCM2835; Linux 4.19.50-v7+ armv7l
    • OS: Raspbian GNU/Linux 10 (buster); Firmware #896
    • Java Runtime Environment: (build 11.0.8+10-post-Raspbian-1deb10u1); Version 11.0.8" 2020-07-14
    • openHAB version: 2.5.9 Release Build (openHABian?)

Dear community,

I have a Wemos D1 Mini (Tasmota) with a BME280 in our bands rehearsal room to monitor the temperature and humidity. The Wemos sends both data via MQTT to openHab which is then forwarded via the persistence binding to an influxdb to have nice visualization in Grafana. So far, so good.

Here is my issue: the humidity of the BME280 is not really accurate (temperature on the other hand is ok). Therefore, it would be great to simply add the value “6” to my Proberaum_Luftfeuchtigkeit item with a rule in order to have a more correct value.

I could to this in Grafana, yes, but I want to have the correct value also on my sitemap/HABpanel.

What would be the best approach? A rule? How does it have to look like?

rule IoT_Proberaum_BME280
    System started
    Item Proberaum_Luftfeuchtigkeit changed
    Number Proberaum_Luftfeuchtigkeit + 6
    Proberaum_Luftfeuchtigkeit_FIX with postUpdate

Do I need a further item for the new Proberaum_Luftfeuchtigkeit, for e.g. Proberaum_Luftfeuchtigkeit_FIX?

Thanks for your help, I am still a beginner in these regards.

Have a nice christmas holidays

Usually you find these settings on the device software (ie. Tasmota)
Check: humoffset

You could solve it by a rule but using the built-in functionality is probably better

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