Flows and the use of ”becomes” rather than ”is”

Hi all,

I’m new to Homey and I’m still figuring out how to use flows in a good way. I have used ST for many years and have come accustomed to use the argument “is” or “is more/less”. For example I have a humidity sensor which I want to trigger a humidifier if the humidity is a certain value, or more or less than that value. I’m only seeing the “becomes” argument in Homey flows which is much less useful in my opinion since it requires a change for it to trigger rather than current state and/or change. For example if I want to keep the humidity in a certain room above 40% but the humidity sensor is showing 35% from before then “becomes less than 40%” does nothing whereas an argument like “is 40% or less would”. Any suggestions on how to solve my dilemma?

The trigger is humidity has changed
In the “and” with logic tag humidity < 40
That would do the trick.


Thanks for your reply @Wilfred_Greven! When is “humidity has changed” now but I’m unsure on how to use log tags in the next step… Help is much appreciated.

Is this on the right path perhaps?

Sry for spamming you but I think I understood the use of tag values now:


The closest resembling logiq I could find was “value is exactly…”

In logic there is a card “is smaller then” (sorry this one is in Dutch):

Then you choose the humidity tag (that was ok) and as number only 40 (with “<“ I ment smaller then) so: humiditytag “is smaller then” 40

Thanks again :slight_smile:

I’ve tried running it but nothing happens I’m afraid. The logiq tag is humidity on the built-in sensor on the humidifier itself.

And the humidity is lower then 40?

I’m afraid so…


Another thing, if this flow started to work, wouldn’t it then trigger everytime a change in humidity was registered? It would be quite natural that the humidity increases when the humidifier is turned on, I don’t want it to run more than once each session.

It triggers every time the humidity changes and the time is between 18.30 and 21.30 and humidity is below 40.
If you want that it only starts one time, you can add a card in the “and” with “purifier is not running (or started). It is purifier dependent if this is necessarily.

For stopping the purifier i would make a second flow.

When the purifier is off, gets Homey the humidity from the purifier?

Thanks, makes sense!

Yes, humidity is still reported while the humudifier is in standby. Can’t figure out why flow doesn’t seem to work!?

Is it the right tag? The tag from the purifier and not the tag from Homeystandard (weather).

Make a short flow:
Trigger: this flow is started
Then: start purifier

Does that work?

I believe so:

Yes, a short flow like that works.

Does it have anything to do with the triggers value not correlating to the logiq tag value?


I’d like to explain this card;
These type of cards work like a thermostat.

-value becomes less than 40%
-turn device x on

-value becomes more than 40%
-turn device x off

The “value becomes less than 40%” only triggers when the previous value was more than 40%.
It does not trigger again when the value is 39% and drops to 38%

That is why i tolled to do it with a logic card, then you can compare the humidity with the border you want (humidity is smaller then 40).
Lets say the border is 40 it triggers the flow also when humidity drops from 39 to 38.

You can try the logic card with the local tag humidity which comes available with the card (when section) purifier humidity changes.
There was a time that this not worked in Homey, so i take every time the tag from the sensor, plug or whatever.

I only wanted to explain the difference

Thanks, it was understood and the main reason why I created my post since I think that logic isn’t sufficient for a lot of use cases. Any device which isn’t running 24/7 might fall below or go above the threshold values and since it’s a fixed value the trigger might not get triggered again.

See my reply why to use the logic and the “when humidity changes” that triggers.

Have you tried the flow with the local tag?

There is only that one local tag that I attached in previous image, #value that is available, not surprisingly it doesn’t do anything.