Is there something in the Rule Machine that would let me add to the trigger, or add a conditional trigger something like this:
IF temperature is >= 100 TURN ON ATTIC FAN
But I really only want this to trigger if the temperature rises more than .5 degrees in 2 minutes. (I might change those numbers after experimenting). I don't see anything like that in Rule Machine. Am I missing it?
Or just setup a periodic rule (every 2 mins) to calculate a global Hub Varb such as:
DeltaT = (Current_Temp - Last_Reading)
Last_Reading = Current_Temp
and have that just continue to calculate on your defined "rate" interval.
Then a separate rule, where if DeltaT > Limit (0.5 in this case) is the trigger condition that turns the fan on (include a required expression that the fan is off?)
Obviously, you need some logic to turn the fan back off, but that's left as an exercise for the reader...
Then you can even do some graphing (Watchtower, or others) on the DeltaT to see what it's historically doing, if that's interesting or you need some history to determine the ideal rate and limit.
