I, and many other Australians have HVAC systems that use 2 wire thermostats that can't (without a deal of difficulty) be replaced with smart thermostats such as Ecobee or Nest. Therefore no easy Hubitat integration that way.
A Brivis/Rinnai system such as mine can have a WiFi module (Rinnai Touch WiFi Kit) attached to provide app control. With this said, there is no native Google Assistant, Alexa integration etc.
My setup is a 3-Zone ducted heating and refrigerative cooling system, with 3 separate thermostat controllers. I recently installed the WiFi controller and it is a good step in the right direction, but my dream is to be able to replicate the Rinnai Apps functionality in Hubitat. Then dashboard control and a myriad of rule functionality will be possible.
Some people much smarter than me have found a way to do this with Home Assistant and Homebridge, so in theory it should definitely be possible for Hubitat to do the same.
My question - can either the Homebridge Plugin or HA solution be "converted" to a Hubitat App/Driver?
Full disclaimer: I know nothing about coding, programming etc. I can just about follow basic instructions to install user drivers and apps, knock up some basic rules etc. but that's about it.
Edit: Note: It would likely be possible to use one of the above solutions and then bridge HA or Homebridge to Hubitat, but I want to avoid having to run an RPI or server and manage another home automation instance on top of Hubitat.
That would be my assumption as well - If people were able to create a Homebridge and a HA solution that can integrate then I wouldn't see why it wouldn't be possible to do the same with Hubitat.
Now, the million dollar question is how easy it would be to replicate either of these two in Hubitat.
If it was a task that took a matter of hours as opposed to days, I would even commission someone on an hourly rate to assist. If I want Hubitat integration the alternative is to buy a zone control board that will allow use of something like an Ecobee thermostat, so I'd rather pay someone that could give app functionality to anyone that wanted it.
Ecobee seems to come with solid recommendations. From talking with others in the same situation, adding an analogue 529 board or a SmartZone control board to the Brivis HVAC would allow use of just about any smart thermostat - Ecobee, Nest, Wyze et. However, for a zone board and 3 smart thermostats it could cost upwards of $1,000, require a bunch of re-wiring, and likely void certain warranties.
Integrating with the native WiFi controller or app would give users all the same functionality without adding 3rd party hardware.
Ok, it's definitely doable - however, it's way past my current skill level with Groovy.
I think you'll need the help of a real dev like Simon ( @sburke781 ) to make this integration - It looks to me like it'll need an App to manage the Authentication and a Driver to manage the device.
Although it wasn't/isn't my preferred approach, given the amount of work that would be required - spinning up a Home Assistance instance to use the existing solutions and then bridging to Hubitat may just be the best way to go.
Thank you to everyone that has weighed in on this. I might try and setup the portable HA on a spare PC and see how that goes. I'll be sure to report back.
Based on what I am reading, you could do all of this in a Hubitat driver, assuming the TCP port is predictable. If that port varies, you won't be able to do it at all directly with Hubitat, because the port is reported in a UDP broadcast packet from the device (which Hubitat is unable to receive).
Assuming that the port is the same, you could get that info from another machine and then write the Hubitat driver for it. The API looks pretty well documented and likely need to use either the Telnet or Raw Socket interface.
EDIT: it looks like the port is hardcoded in the HA integration, so this is fairly straightforward to at least get a connection started.
TCP is probably a little outside my comfort zone, I have mostly used REST API's so far. But happy to help where I can. I'd agree with most of what has been mentioned so far, a driver and possibly an App would be the way to go, but also agree with trying the HA route first, and if that works seeing what you think about writing some kind of integration in HE.
@GrumpyTeddy, try downloading the Putty application and connect a telnet session to the IP address of your Rinnai Touch Wifi module and port 27847. Does it connect and reply with anything?
Having never actually used Home Assistant I set it up on a spare mini PC using VirtualBox to have a play. Definitely a bit of a learning curve, but I can immediately see the appeal - almost instant and easy integration with Chromecast that gives full control, album art and media info, immediate RTSP streams to my Unifi Protect cameras, and so much more.
I have begun setting up the integration for Rinnai/Brivis using Funtastix solution in HA (Home · funtastix/rinnaitouch Wiki · GitHub) and it looks like it will be exactly what is needed.
I wanted to initially get this happening natively in Hubitat so that I didn't have to run Home Assistant or Homebridge. However, having now seen what HA is capable of I have actually used an integration to link Hubitat and may just start using HA more and more.
Thank you to everyone for your input, and time. All the support is much appreciated.