To control the winter humidity in my house, I use a relay to turn on/off the humidifier on my furnace. Using the external temperature, it calculates a target interior humidity level. If the indoor humidity read in one of my humidity sensors is less than the target, it turns on the humidifier. If it is higher, it turns off the humidifier. The webcore piston is:
Is there any way to do this in Routines?
I can’t imagine a way to do the calculations as they are being performed in Webcore.
But I think you could some level of similar control with multiple routines.
One routine could have two conditions in the IF statement:
THEN turn OFF or ON the humidifier.
You could make another, or several more just like it , although changing the X above or below to different ranges
That’s how I’m imagining it at the moment, there may be some flaw in my logic, though.
I’m thinking others may have some ideas, as well.
My be something that you can do with Sharptools.
Custom Math Expressions are at the top of our shortlist! It’s one of our top requested features, so once we finish up the SmartThings Next Gen work, we plan to revisit it!
Edit: We introduced a math feature to our Labs environment until we get a chance to build this out as a first-class feature. 
Edit2: Math and Date Expressions are now available in SharpTools!
Here’s a quick example of some of the neat things you can do with expressions. I was moving pretty quick to keep it under a minute so feel free to pause as needed, but the video includes some basic math with variables, date manipulation, logic and more!
You can find some documentation on the features and functions here:
It will only be urgent once heating season is upon us. I am looking forward to the new hooks for Sharptools and maybe I can implement it there.
That was my thought, but with a 200 automation limit… It also makes it very mucha a step function rather than a smooth applicaiton. I doubt it would be noticed, but my engineering brain doesn’t like approximations when an actual value could be calculated.
Totally understand.
Even if 200 routines were not an issue, the indexing of, and creating them is tedious.
I keep telling myself I’m going to have a long sit-down and figure out the Rules API, but until I have an absolute requirement, I’m hesitant to make that commitment. Or maybe I fear that my brain isn’t quite as sharp as it used to be.
Also hoping routines evolve to a place where it won’t be necessary, eventually.
Hi @KenW48360
If you use zigbee temperature and humidity sensors, these new features of this driver may help you move to app routines
Just an FYI that I posted an approach that should work if it becomes urgent.
Edit: And it’s available natively as an expression editor now!
