Arduino™ ADK Android Rev3
The Arduino ADK Rev 3 is a microcontroller board based on the ATmega2560. It has a USB host interface to connect with Android based phones.
It is compatible with Android's Accessory Development Kit examples. It has 54 digital input/output pins (of which 14 can be used as PWM outputs), 16 analog inputs,4 URTs (hardware serial ports), a 16MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button.