I've just finished my project. It controls the Arduino over bluetooth
from your Android device. The best thing is that the UI is stored
in Arduino and you can create any UI you want. You can also
use any hardware you want unless it is able to connect to the smart
device through bluetooth.
Here is the example on youtube: https://www.youtube.com/watch?v=WAr--diq-AI
The full source code and setup is on my blog: http://visiduino.io/sk/blog/visiduino_app_c_interface/
You can use it for your project too for free.
Here is the app: https://play.google.com/store/apps/deta ... .bluetooth
Wish you nice day
Lubo
