Arduino Mega ADK
The Arduino MEGA 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 15 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.
The MEGA ADK is based on the Mega 2560. Similar to the Mega 2560 and Uno, it features an ATmega8U2 programmed as a USB-to-serial converter.