Appropriate power supply (via usb) for adk mega to connect to android device

Development Tools IDE 1.x
1

Dear all,

I am trying to connect a android device to a arduino mega adk board to read sensor data. Everything works fine as long as the arduino board is connected to my PC via USB.

However as soon as I try to supply the board via a external USB power supply or via a external power supply (e.g. 12v, 2A) the Android is not able to establish an USB connection with the Mega board. If I switch back to the USB cable from the PC, the Android USB connection is established again.
I assume this is because the current delivered via USB is varying and sometimes too low (my external supply delivers 1A). Before I now go an buy a new USB power supply I would liek to hear your recommendations on this issue. Mabe someone has made the same experiences and has a good solution.

best regards,
Robert

2

Why not use the power jack and skip the USB part?

3

Thank you very much for your quick reply! Yes, power jack would also be OK, but during a first test with a 12v, 2A the USB connection with the Android could also not be established but should work according to the specs which recommend at least 1.5 A.