Hi Kas,
Yes ...I've used your Android App as the front end of a B.T. controlled wheelchair.
Thread here ... WheelchairDriver • View topic - PINNED - Plug & Play PGDT for Radio Control ... the last few pages WheelchairDriver • View topic - PINNED - Plug & Play PGDT for Radio Control about the B.T.Cheers Woody
Interesting 
Feel free to propose any App modification
I have worked with a british artist on this project
The robot was based on wheelchair motors, and fitted with proximity sonic sensors to avoid bumping on furniture/people
I also suggest using a simple "dead man" failsafe in your code, to stop the chair if BT signal is lost