I am currently preparing a series of blog posts to explain, how I connected my rapsberry pi based sprinkler system to my Google home. I will share code an insights about my journey.
You will need a raspberry pi (any generation is fine, I run a 1.gen) and a Google Home, or just your smartphone with google assist enabled. The more impressive is the Google Home though.
I will explain how to setup the raspberry pi, how to obtain a hostname for you dynamic IP address, the setup of letsencrypt certificates on the rasberry pi, how to auto-renew them, how to write a plugin for the rsiServer (http://github.com/rsiServer), how to setup the server for Token based authorization, how to enable https and finally how to hook up the Google Home to the entire system.
Please give me a little time and support me by sharing the announcement, I will be back with detailled instructionssoon.