Why add a mosfet as device ?? It’s nothing like that, it’s just a transistor ! If you want to control it with a GPIO of ESP, just declare a GPIO at output switch and it should do the trick no ? 
Thank you very much @vincen.
Thats the reason why I’m was asking here for help.
Such a great community!
But after some trying and looking around a bit I flashed ESPHome.
A great piece of software for a beginner like me that simply harmonizes perfectly with HomeAssistant.
Many thanks to @OttoWinter fot this!
I get the sensors up and running right away with it. Now everything works, including self-sufficient power via a solar cell. 
Now I just have to make it a bit “pretty” so that it will be accepted by the lady of the house 
Yep ESPHome is definitively for me too one of the nicest firmware currently avalaible for ESP with HA All the more with API native link ! Be careful that it might still be better to use old way with MQTT broker for some specific applications (often when you use deep sleep mode and where you have to save energy as you don’t control when ESP comes back to life time API will take to connect back, which is not a problem with MQTT as it’ll connect back as soon as network is working in ESP !)