I have a ventilation system in my house which is broken. A #repair would cost 2500 Euro but it is a dumb system without home automation. I am right now soldering my own control unit together which I was working and testing for some weeks already based on an #ESP8266 . I estimate the total cost of this repair to be 150 Euro and it will have way more functionality afterwards, will be easier to repair and has #HomeAssistant integration. If it works I will #OpenSource the stuff and put it on #Git.