Normally smartphone events are tightly coupled to your phone device
itself. When your cell phone is ringing, your phone speaker plays a
ringtone. When you get a new text message, your phone displays it on its
screen. Wouldn't it be thrilling to make those phone events visible
somewhere else, on your wearable, in your living room, on your robot, in
your office or where ever you want it to occur? Or would you like to
use your smartphone sensors, like the accelerometer, light sensor,
compass or your touchscreen to control other devices?
Amarino is a toolkit, basically consisting of an Android application and
an Arduino library which will help you to interface with your phone in a
new dimension. You can build your own interfaces almost without any
programming experience.
http://www.amarino-toolkit.net/
The Arduino ADK is a microcontroller board based on the ATmega2560 (datasheet). It has 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.
http://arduino.cc/en/Main/ArduinoBoardADK
