Remote leveler for iOS and Android

Hello everybody, this is my first topic here.
I’m a mobile app developer: I develop crossplatform apps with Ionic Framework and Cordova.
I need to build a small device: a “leveler” sensor that helps me to level my caravan. The sensor must be something like a MPU-6050 that send, in realtime, data to my apps using bluetooth. I can use this library to handle the bluetooth connection:

I need your help for the hardware: following the guide on github if I want to use iOS I need specific bluetooth module. Now I need a sensor and of course Arduino: any suggestion here?