Thanks a lot.
I will start by getting the heads and tails of MySensors by doing a setup in my WiFi covered house.
Then I will see if the controller can work without internet, with a phone controlled ble Interface instead.
If this is not possible I will see if it is possible to communicate with the gateway from a phone instead.
Let’s see if it I get anything working before Christmas...

Dear hackers

I’ve bought a caravan and would like the drown it in sensors.
The question is if MySensors is the way to go. There is no Wi-Fi in the caravan.

Does a controller exist that I can extend to serve values via Bluetooth that I can read from a mobile app?

The idea is to have AA-battery powered sensors talking to a gateway attached to the caravan battery (only turned on when caravan is in use).
The gateway (a rasp pi or an Arduino?) should when powered on receive and log sensor values. From a ble interface a mobile app (that I create) should read and present sensor values.

Bonus question: is it possible to buy an off the shelf board with deep sleep and nrf24l01 already soldered? Does “StableNode” exist?

Bonus info: I have app developer background and is bad at soldering.

Best regards
Henrik