In my home, I have a mechanical ventilation system with heat recovery powered by Stiebel Eltron V-400. Basically, it’s a large fan with air inflows and outflows ducts. Besides some built-in automation, it’s a pretty dumb device. Without a dedicated gateway (which costs extra money), I can only control it or see its current parameters on the controller, either on the unit or in the hall.
I thought it would be nice to collect some data from this device, both for some kind of analysis and out of curiosity. I run Home Assistant, which can display dedicated graphs and dashboards for such purpose. And, because I recently played with ESP boards, the idea was born pretty quickly.