Add Home Assistant integration documentation

[enoch85]

OVMS Home Assistant Documentation Overview

This documentation provides a comprehensive guide to integrating Open Vehicle Monitoring System (OVMS) with Home Assistant. It covers:

• Step-by-step instructions for setting up OVMS modules to communicate with Home Assistant using MQTT protocols, with accurate data usage expectations and performance metrics.
• Multiple implementation approaches, including the automated integration method (with HACS) and manual YAML configuration options to suit different user preferences.
• Detailed security implementation guidance for establishing secure TLS/SSL connections between OVMS, MQTT brokers, and Home Assistant.
• Practical optimization strategies to minimize data usage while maintaining functionality, with specific recommendations for both V2 and V3 protocols.
• Troubleshooting resources and configuration examples to help users resolve common integration challenges.

[enoch85]

@dexterbg I'm open for discussion on this one.

[enoch85]

Here's a good read about MQTT overhead: https://medium.com/@dheeptuck/how-to-optimize-data-usage-over-mqtt-792abebd2cd1

[enoch85]

cc @markwj as well. 👍

[CrashOverride2]

Interesting! I thought about the same, but I use another approach I get data with integrated REST API from OVMS-Server v2. I use a multi SIM tariff with 150GB traffic so this is not a problem on my modules, but I still use v2 protocol because I like its efficiency.

I grab data from the modules with HA's integrated REST API function to poll these from my OVMS Server. Of course if public servers are used, there should be a limit how many polls per day should be allowed, in this case MQTT might be better.

If you like it and want to add it to your documentation, I attached the yaml file for home assistant. Of course this works with HTTPS encryption too.
ha-rest.yaml.txt

[enoch85]

@CrashOverride2 That's super neat.

My first problem as a new user though, I want ALL the entities(!) - and without knowing how to tinker with the OVMS module, I created an integration that does it for me. 👍

[CrashOverride2]

Ah ok this makes sense! In my first days with OVMS (2022) I want all metrics too and created a nice Grafana dashboard, but thats still too many, never looked at the dashboard again execpt for the first weeks of course :-)

[enoch85]

I don't really care either, but thought I'd try, and it worked! The integration gives me ~175 entities for my VW e-UP, but I only need like 4. 😂

Anyway, I made it to make the step into OVMS easier, and we'll, it works. :)

MQTT is the future, and in 5 years it may be at the same stage as V2, so that's the reason for my decision. It also integrated nicely into HA.