Cavius smoke detector integration?

Since I can’t find anything by googling “Home Assistant Cavius”, I guess the answer’s “no”, but still:

Has anyone tried integrating the Cavius smoke detector system with Home Assistant?

Cavius wireless alarms wirelessly interlink with each other (so they act as “dumb” smoke detectors), but they can also connect to a hub (thereby becoming “smart”) which is said to work with Google Assistant. I therefore suspect that it should be possible to integrate them with Home Assistant somehow.

It’s time to replace my smoke detectors, and the Cavius line looks promising, but I would prefer something that can be integrated with HA.

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Have you discovered anything new on this topic?

Sadly, no. I am still eager to hear if anyone knows anything.

As I said above, Cavius says their hub works with Google Assistant, so there must be an API of some sort, but I haven’t found a description, nor have I found any report of someone integrating it with Home Assistant.

We’ve just started selling the Cavius products at work, and I’m eager to be able to integrate them into HA as well. I contacted the main distributor regarding information/documentation for their hub and/or protocols, but I got harsly rejected.

Unfortiunatly that means the process is going to take longer and add quite a bit of manual labour… but I hope we still can get there.
I will certainy try to hack the shit out of it when I get the time.

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Have you had any chance to look at it? I plan to add 12 mains powered smoke alarms and their hub. Would be great to have it integrated with HA.

Quick update. Looks like the HUB from Cavius is produced by a Danish company called Nabto

Nabto has documentation available here

Any news in this topic?
I plan to by the cavius smoke detectors and the hub for my home, and i would love to get this integraion :smiley:

I’m afraid it’s out of my scope. Hopefully someone else can pick up on this.

I ended up getting Cavius for our new house (soon to be installed). Simply because I wanted wired devices with some sort of smart features. This was the only device I could find suited for Danish building regulations.

I’d also love to see some developments here. I had some existing Nest Protect units kicking about, but it seems that I won’t be able to use them in my new home because Building Regulations in the UK require that we have a mains-powered heat detector for the kitchen, and Nest Protect is not compliant.

Cavius seems a good option, but I’d love to see if I could get some form of smart functionality integrated with HA… I just wouldn’t know where to start.

Hi again …

@cphassistant It’s not just the HUB that’s Danish, the whole Cavius productline is.
They’ve just opted to use Nabto as their IoT backend.

From my inquiries with our distributor I understood that part of the reason for choosing Nabto, were their focus on security and ability to encrypt the datastream.
Given that information, I’m suspecting some form of encryption from the dongle to Nabto. This would make eth packet-sniffing useless. (But I haven’t tested it yet. For all I know there’s even a local API, but I doubt it)

It’s more unlikely that they’ve encrypted internal RF traffic, but it’s to early to say for sure.
I’ve just started the work of sniffing and reverse-engineering the RF protocol. But it’s a rather tedious and time consuming task.


Just a short update; The wireless protocol is now (more or less) mapped out. There’s a couple of bits left to tag in the payload, but that’s most likely used for sensors/devices I currently don’t have access to.

I guess the next step will be to implement this in rtl_433, as it’s (probably) going to be the fastest way to get the result to HA (via MQTT)

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Good job!


I guess the next step will be to implement this in rtl_433, as it’s (probably) going to be the fastest way to get the result to HA (via MQTT)

So, the wireless communication between devices and hub is on 433 MHz?

Does the hub talk to the devices as well or just devices->hub? If there is a two-way communication, one could consider using something with a transmitter as well (RFXTRX433XL, for instance).

EDIT: Typo

These devices communicates in the 868 Mhz ISM band. (Despite its name, rtl_433 is frequency agnosic. It just reflects where it all started)

The HUB is capable of two-way communication and the app uses this for some of it’s features. (Firedrill, periodical testing, etc)
Personally I think the RFXTRX433XL is a rather overpriced piece of hardware for what you get.
I’d rather use a Yardstick ONE in that pricerange.

It should be possible to make a “full-featured” HUB with ESPxx and an RF-chip, running ESPHome. (~ $10)
I am however, somewhat concerned about implementing a two-way system. This is after all the -one- system in my house that can not fail! It’s literally a matter of life and death.
It’s probably not a big deal, but absolutely something to reflect upon.

Another thing is the infamous “why”?
At this point I’m not sure it’s worth the effort to implement Tx, since the only added feature set exposed to HA (that I can think of) will be:

  • Pair new devices
  • Put units in test-mode
  • Sound the alert/alarm
  • Mute the alert/alarm

(That said, I’ll be surprised if I don’t make a hub, just for the challenge)

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Haha, yes, I agree, smoke detection should be just a safety system and one should take care not to mess too much with it (if at all).

And, yes, my view on it was your answer to the infamous “why”: Because we CAN. :wink:

Anyway, getting it into rtl_433 is a good place to start. I have a couple of instances running, and one can be moved to 868 MHz.

Another update;
We’ve just got our PR to rtl_433 approved and merged. :slight_smile:

As soon as the next version of rtl_433 is out, all you need to do to read your Cavius devices is simply to run “rtl_433 -f 868.68M -s 250k -R 179”

By using the -F flag and mqtt your data should be in HA in no time :slight_smile:


Well done! :tada: :clap:

@hhovde I’ve (finally) set up as you proposed (rtl_433 -f 868.68M -s 250k -R 179), but get nothing (I’ve waited half an hour or so). Have you noticed how often the Cavuis detectors transmit? I’m wondering if they transmit very seldom (and that’s why I haven’t seen anything yet) or if my rtl_433 instance is not working as expected.

Just caught this thread, as I am trying to see if I can get some data from my Cavius smoke alarms as well. Using a standard (cheap) USB stick with a R820T tuner…
I have tried the command “rtl_433 -f 868.68M -s 250k -R 179” as well, but doesn’t really see any output (just tried to remove the battery from one of the detectors and re-inserting it, to see if that could initiate some traffic)
Update: I suspect that battery level only is sent in case of events on the detector, that means testing, pairing, smoke detected - and low battery…

Yes, the Cavius detectors claim that they have five years battery life, so it might be that they only transmit when something’s going on, not just to say «hey, I’m fine». Although, how can the hub be sure that the detectors are fine if they don’t (once in a while) transmit a «I’m here» message?

@uphillbattle and @bipsen;
First and foremost, make sure you have the latest version of rtl_433. The PR where accepted back in February, and was officially added to rtl_433 in version 21.5, released in May this year. Usually linux repositories is lagging a bit behind. You can download and install the latest version directly from github if needed.
To get your running version, run “rtl_433 -V”