Grohe Sense (Ondus)

Would be great with a component for Grohe Ondus that supports their smart sensors for water detection and water guards. Also lets you measure temperature and humitdy in the rooms where you place the sensors.
Anyone with the skills?

The also have a different app for other things “Sensia Arena” for their toilet for instance, don’t know if it works the same way. But I would also like a component for the ondus.

I don’t know if this can help as a starting point, but there already is a binding in openhab:

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This Java client could also be helpful:

+1 on this!

I will get one of these to lower my ensurance cost and would be very happy to see it integrated in Home Assistant.


+1 for this, have one as well in the kitchen.


I’ve looked a bit at this, and started looking at what data one seems to get. From the sense guard itself, it seems to store water usage data since installation (at least since Feb, when I installed mine). There are point-in-time data points like
{"timestamp":"2019-03-03T00:59:47.000+01:00","flowrate":0,"pressure":6.6,"temperature_guard":20} every 15 minutes, and consumption fields with data like {"starttime":"2019-08-04T22:57:20.000+01:00","stoptime":"2019-08-04T22:57:41.000+01:00","waterconsumption":1.4,"maxflowrate":4.2,"hotwater_share":0.4,"water_cost":0.05599,"energy_cost":0.019155} (I have no idea where it gets the hotwater data from as it is just on the in-flow for cold water, or how accurate it is). One really annoying thing is that there does not seem to be any consumption data generated if you leave a tap dripping.

Any ideas for what sort of sensors you’d like to see in Home Assistant? Water consumption today? Total water consumption since beginning of time (or at least as long as the data goes back)? Or is there some entity type suitable for long, historic, data series?

I haven’t seen anything on getting alerts/alarms (e.g., “long-lasting withdrawal”). Does anyone have enough familiarity with the openhab bindings to know if they’ve figured something out there?

Thanks for looking into this, appreciate it a lot!
I myself only have the humidity/temperature sensors and would from there be able to see actual and historical data.
When it comes to the water guard you mention I think water consumption in different time periods along with total consumption makes sense!

No worries, I’ve been meaning to take a look at this since I installed my sense guard in Feb, just hadn’t gotten around to it until now. I put together something that has managed to run at least a few minutes for me without crashing, so I put the code on github for anyone brave enough to try it out: .

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Great, very nice to see people starting with this, the ability to turn on and off the water would be nice. Maybe the ability to “show last water whitdrawal” or something, not sure if its useful, but maybe cool? (type 14.42 there was a 5 minute long withdrawal the used 40 liters)

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Finally got time to look into this but get stuck on the login to Grohe-part…
Tried to use the the same user I have for the Grohe Sense-app but that just leads me to a blank page… Any ideas?


Sounds like you’re at the step where your browser will be redirected to an url starting with ondus://, is that right? That URL won’t render as anything. Are you using the developer tools in Chrome (or equivalent in other browsers) to catch that redirect to extract the URL and change the protocol to https?

Thanks for clarifying, I think I managed to get the token out and input into the config but now I get a message in the log saying:
"Setup of platform grohe_sense is taking longer than 60 seconds. Startup will proceed without waiting any longer.

20:50 helpers/ (ERROR)"
Any ideas?
Running om version 98.5


You’ll need to turn on a bit more debug logging to get something useful to debug with. Add something like:

  default: error
    custom_components.grohe_sense.sensor: debug

(or, if you already have a logger config, just add the grohe_sense to the one you have configured. That should give you significantly more debug log to get some sort of indication as for what the problem is.)

One way I could see this happening is if you did not copy the refresh token correctly. If that’s the case, I’d expect log lines with OAuth token refresh did not yield access token! Got back (logged at an ERROR level).

This is really great, thanks a lot for your efforts! Works great in my installation. I really do miss possibiity to turn water on and off, as well as getting alarm on leakage. Any chance this is possible to integrate?

Happy it’s appreciated! Adding actions to turn water on/off should be relatively straightforward, I’m pretty sure that functionality is already present in the open source java library. I’ll add that to my todo list. Out of curiosity, what would you use it for? I skipped implementing it as I couldn’t come up with a place where I’d want to use it myself.

As for alarms, those will likely require a bit more work, but I can look into it. My gut feeling is that it’ll be hard-to-impossible to get real-time alarms, alarms would likely be fetched via polling and I’m not sure how tight a polling interval the API will tolerate. Do you have a feel for what delay would be acceptable to you for getting an alarm into HA? 15 minutes? 1 minute?

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Thanks! That’s much appreciated. I would use it to automate turning water off when the house is empty. Also, I have some z-wave leakage sensors that then would be possible to use to turn water off if there is a leakage.
Regarding alarms, I would say anything is acceptable compared to nothing as today. I don’t trust these proprietary apps, especially from companies that core business relies on something that is nowhere near IT or home automation. So I would appreciate to get notified of a leakage even 30 minutes late, when the Grohe app has stopped functioning or have logged me out or something.

Great stuff.

I’m really looking for alarms, and as Erik says anything is better than nothing. Thanks for doing this :slight_smile: