The Arduino ADK is a microcontroller board based on the [ATmega2560](http://www.atmel.com/dyn/resources/prod_documents/doc2549.PDF) with a USB host interface to connect with Android based phones, based on the MAX3421e IC. It has 54 digital input/output pins (of which 14 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button.

For information on using the board with the Android OS, see [Google's ADK documentation](http://developer.android.com/guide/topics/usb/adk.html).