Thanks 
as long as a cheap bluetooth dongle set’s up a serial port upon successful pairing and device setup (I believe it’s always the case), then you can specify that the application should connect to it. I’ve added description how to do it in the README
I haven’t tested yet how well does it work with BT, but I assume it shouldn’t be any worse than with USB. I’m not able to test it with RPi, because I don’t have the BT hat.
Anyway if you were to test it with RPi and BT please let me know, so we could get some robustness changes implemented if it misbehaves
