Android studio, Arduino, usb

Hi all.
I'm trying to pass data from my Arduino, via USB otg, to an app, debugging via Android Studio..

Arduino side -
basic IDE, simple sketch :

  • basic joystick. read analog pins 0 and 1, Serial print the readings. Working fine.

now I want to connect it via USB otg to my phone (i.e. Galaxy S5), which is being debugged on
Android Studio,(before you ask - I use wifi adb, so the actuall usb can be connected to the Arduino).

I've been around the web for a couple of days. Buzz words that popped up were:
"microBridge", "adb.h" "SerialUsb", and others..

I'v done my homework, and I'm a software dev, and yet..
I cannot (for the life of me) manage to pass that simple data from Arduino, to my phone.

NOT interested in Bluetooth or wifi, nor in Proccessing, or usb shields.

P.S. Also looked into trying to use 3.5 audio jack to pass data (Both ways),
but that got me even less tutorials and actual examples / samples etc.

Any ideas?

For your services to be recognized as external input, you need to provide the correct protocol. You can't just send raw data and expect the OS to understand, it's not that smart (they are called smart phone I know but...). Which protocol is I do not know. But I'm sure you can figure it out since you're a software dev.

That’s exactly the problem. In theory, USB class can take in serial data,
but I would rather find at least a half written class than actually write it from scratch.
I just find it strange that no one does it.
IMO, that’s the simplest, easiest way to communicate.
Write to serial, read from serial…

using Bluetooth or WiFi shield is taxing on the phone side,
having to go a full day or more with data IO.

The 3.5 audio jack would be the best, but all the code classes are close-code,
and couldn’t find any good working open-source