NOTE: since i don't want to root the phone, we need to use the android libraries to communicate on usb:
read this: http://developer.android.com/guide/topics/connectivity/usb/host.html
The question is: what data format we will receive from the pm3 connected to the smartphone by using the android libraries?
could we directly communicate like the client does, or do we have to develop a driver layer protocol?
I suppose the first one is the answer.