MQTT and home-assistant

[Andrew Elwell]

Morning folks,

I've been running weewx with mqtt publisher for some time, and having recently done a complete refactor of my home-assistant configuration realised it's a bit of a pain to add each sensor to the configuration.

So: my plan is to patch the mqtt add-on to include a "enable home-assistant" configuration flag, and then get it to publish the configuration details as per https://www.home-assistant.io/docs/mqtt/discovery/

I had a quick look on GitHub and can see there are a few forks of Matthew's original (https://github.com/matthewwall/weewx-mqtt/network) - is anyone interested in picking up the suggestion or should I just fork and submit a PR in the normal manner? (Not sure if Matthew lurks on here)

Andrew

[mwall]

hi andrew,

i am still lurking.  i should (finally) be updating my weewx code as we go into 2021.  2020 has been brutal...

m

[Richard G]

I’d be interested in the HA integration, I’ve added a few values but it’s very tedious. Happy to test anything.

Richard

[Andrew Elwell]

> I’d be interested in the HA integration, I’ve added a few values but it’s very tedious. Happy to test anything.

Work in progress screenshots on
https://twitter.com/elwell2000/status/1340642986955132929

It looks like I'll need to send the config payload every loop - this
doesn't seem to be an issue in home-assistant but otherwise (AFAICT)
the publisher doesn't have any advance indication of what key/value
pairs to expect to then publish. Related to this is the difficulty in
working out how to assign a 'device_class' to each of the measurements
- I can probably guess some via regexp (key ending _C is likely to be
temperature for instance)

anyhow, gardening took up most of the weekend, so I won't be pushing
my branch publicly till it's a bit less crufty. I'd *hope* to have
something others can test some things with by this time next week.

Andrew

[vince]

I'm a little lost re: what you're doing and why it's needed.

What i did was install the MQTT extension to weewx so that weewx emitted MQTT data to a MQTT broker running on a pi3.  I then subscribed to the readings I wanted in HA (temp/rain/wind) and added those elements to my HA dashboard.  Nice and simple.  Adding 'three' MQTT subscriptions to HA was trivial.  No fancy code or anything needed on either end.

[Greg Troxel]

@rest of people: This message is not going to make sense if you don't
understand Home Assistant.


My impression of the goal is to support "mqtt discovery". Basically a
device posts a json dictionary to a config topic, and HA operates on
that data and adds sensors.

https://www.home-assistant.io/docs/mqtt/discovery/

and see "Sensors with multiple values". So the mqtt extension, which
perhaps has knowledge of all the items in the aggregate, would post to N
config topics, one for each item and then all the sensors would just
appear.

I post an aggregate message every archive interval, and I have 12
sensors configured from the large json dictionary that is published. I
ignore a bunch.

Obviously, if added, this facility should be optional in the weewx mqtt
extension. Some people, me included, don't want my sensor list spammed
with stuff they don't care about. I don't mind actual weather data, but
extraTemp4 when I don't have a sensor I defintely don't want. So
probably the extension needs to have some explicit config. This ends up
being a win if the programmatic config saves people time on average.

A comment I sent privately was that I want humiidty units to be "H%"
rather than "%", because when I look at graphs (in HA still) I want to
see humidities graphed together, and battery levels graphed together,
not all on one graph. (I even use V for line voltages, aV for
1.5V-nominal, bbV for 2 x 12V lead acid nominal, etc. Yes, I know I'm
unusual.)


All that said, I can completey see your point that you prefer to just
add a few sensors manually with template sensors.

[wes...@gmail.com]

i think this is a fantastic idea. what greg is doing is awesome.  i'd totally use this.

[Andrew Elwell]

[holy thread resurrection, batman! Yes, I know it's taken longer than planned]

On Sun, 20 Dec 2020 at 09:13, Andrew Elwell <andrew...@gmail.com> wrote:
>
> So: my plan is to patch the mqtt add-on to include a "enable home-assistant" configuration flag, and then get it to publish the configuration details as per https://www.home-assistant.io/docs/mqtt/discovery/

I've started poking at this again, having spent some time working on a
similar thing for our EpEver solar charge controller. Well, that and
annoyance that weewx is saving the values from my FineOffset WS1080
(actually a https://www.jaycar.com.au/p/XC0348) with rounding errors

sqlite> select outTemp from archive order by dateTime desc limit 10;
8.5
8.45
8.46666666666667
8.45
8.5
8.56666666666667
8.68333333333334
8.7
8.7
8.76
sqlite>
but that's another days worry to work out where that's coming from.

Are there any particular functions that get called when weewx is
started, as I don't want to send the configuration every cycle.

Many thanks

Andrew