Automations based on rate of humidity increase

I have had a humidity sensor near my shower for quite a while, but never got it to trigger my bathroom fan nicely. The problem is that the baseline humidity changes day to day and throughout the year, so establishing a rule based on a fixed humidity never worked well. What I’d like is a rule that triggers if the humidity has increase by x% in a span of y minutes or less, and then I would like it to run until the humidity reach (x-1)% less than the present humidity. Does anyone know how to make this happen?


Did you ever figure this out? I am considering moving to Hubitat as automation like this was easy with Groovy but impossible with Edge…

A possible solution is to use the Smartthings rule function Changes to read the increase in humidity, and then trigger a virtual switch.
Set the humidity reportable value [2 o 3?] in the driver settings for the sensor - recommend the Zigbee Temp and Humidity Mc driver - and then use @TAustin’s timer Utility driver to control how it rises, sending a notification when e.g. 3 increases ocour in 10 minutes. Needs a bit of trial and error to calibrate but it can be done.


I did this utilizing TAustin’s MQTT Device Creator. I created a dummy humidistat and a dummy switch. I then created a SmartThings Rule that copies the humidity from the actually humidity sensor to the dummy one. It also requires a RPi that listens for the humidity to be reported on MQTT by the dummy humidistat. The logic for when to turn on/off the fan runs on the RPi and controls the dummy switch. A rule in the SmartThings app then turns the fan on and off based on the dummy switch status.

Check out the discussion here: Edge and Local Control via API or App - #11 by maranhao

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Great, I’m not into MQTT so wouldn’t have thought of that!
Managed to do something similar to what I suggested to get a storm warning using a rapid drop in atmospheric pressure, which comes on the Aqara sensor. Still not perfect yet but I’ll get there.
Will take a look at your link.

Thanks for the detailed reply dude. So much hassle for what should be a simple scenario to automate. Might be time for me to switch platforms to Hubitat. It really seems like ST has gone backwards and webcore runs locally on Hubitat.