I know I'm obsessive but today I hit the milestone of 100 devices connected to MQTT and all accessible to HE in one way or another. Discovery works for about half of these devices and these comprise about 90% of thousands of entities. Agreed not all are useful and some are just one 'device' with lots of sub devices for example I have 2226 entities discoverable from just one Home Assistant device on MQTT. Most of these are themselves devices originated from MQTT but reported back to MQTT.
I have spent a lot of time making my system MQTT centric and I have many many controllers. My aim is to link everything via MQTT rather than any direct controller <> controller API. One of the niceties of this approach is that it's one plugin/application on HE rather than tens or hundreds of different ones.
I don't recommend anything approaching this extreme of MQTT connected devices but it is very helpful in stress testing my MQTT app and knowing it works well ! If you have multiple controllers from different manufacturers then it is the way to implement this.
Because the devices communicate via MQTT then the islands of automation can typically remain functional with minimal assistance eg security, climate, AV, telephony, lighting etc. plus their own control system e.g Sonos etc..
Also pleased to say that device discovery** integrations are now working
or imminent for these controllers:
HomeAssistant
OpenHAB
Athom Homey (but not Homey Hub)
Indigo
C-Bus
Domoticz
HomeSeer***
Vera**
Fibaro HC3 and HC2***
Zipato***
Reactor - network rules engine
Loxone - looking into both of these as I use them
NodeRED integrates very well with MQTT too
** Some discoveries support better device recognition than others.
*** Probably - might require extra work / plugins
..and actually anything supporting homie or HA Discovery MQTT protocols. Individual 'ad hoc' MQTT payloads can be supported too including payload mappings and all these can be used concurrently. This discovery can allow device sharing across different manufacturer hubs similar to HubConnect or HubMesh but both these are faster and better choices within say Hubitat<>Hubitat communication.
PS I am not touting the MQTT integration here.. just mentioning it's capabilities. In fact from a support perspective I hope that only enthusiasts explore it as it has so many permutations and requires a good understanding of the way MQTT works.
