The Lime app reads the QR code and sends that to a server.
The control module inside the skateboard has a cellular
modem with. It either receives a text or keeps a constant
internet connection with the server. When it gets the signal it
activates the power to the skateboard.
Billing is done via the app, there are APIs for that for all
major mobile OSes.
I don't think it directly communicates with the user's phone, all
goes through the server.
Why not grab one and take it apart to see for yourself :^)
ofc i'm kidding. dont do that.
--
Nife Sima - the lower earth crust