I built up the remote control prototype this evening. I'll write the firmware to interface with the phone and then I'll write the software for the phone to interface with the joystick. Once I am happy with all that. I'll figure out how small and cheap I can build it and see if I can get a billet case machined to hold the controls. The computer and charger (the white circuit board under the red control board) will live under the seat or in the weather proof phone case (yet to be designed) and will plug into both the phone and the controls.