Sorry to cut in on your bluetooth request (I thought Dave had put this into his project?), this may or may not be of interest. I'm an existing user of Daves AAF2 project (which is the best Ascom focuser I have come across https://sourceforge.net/p/arduinoascomfocuser/). And I thought you should know:-
AAF2 is now supported in StellarMate Beta (shortly to go live I suspect). www.stellarmate.com Go to support /Misc/ Beta etc. When adding your focuser to Ekos AAF2 should appear in the drop down (pretty much at the top!). It all seems to work well, many thanks to Jasem Mutlaq for writing the driver, now all we need is for he weather to clear and the Moon to go down..
AAF2 (upside down), rear side shown connected to Baader Diamond Steeeltrack. Incorporating Nema 14 stepper, DRV8825 connected to Nano (seperate 12V supply requred)
Load testing. Belts and wheels from BearingsRUs. Fitted into a Cambdenboss 50mm box. The hole in the top there is filled with clear silicone, and shows the power status (incorporated a '12V detect' function and flash pin 13 if not there. Temperature probe not connected here.