[grishka]

> I didn't knew for example that using Bluetooth while the app is shut down was possible.

On modern Android versions, there's some serious limitations on apps running in the background at all. In most cases, if you want your app to run in the background, you gotta put up a notification that is displayed the whole time that background service is running.

Oh and also. Scanning for bluetooth devices is a fairly battery-consuming activity as far as I can tell.