Ready-built module of the Elektor Android Breakout Board, as described in Elektor magazine, edition June 2014.
This Breakout Board for Android smartphones and tablets facilitates I2C-, UART and SPI interfacing with your Android device and allows you to generate PWM signals, while offering seven additional digital outputs -- bridging the barrier between Android OS and your own electronics design.
Combatible with Android 3.1 (Honeycomb) or higher (Android Open Accessory Mode should be supported).
More information can be found at www.elektor-labs.com/node/3960. The June edition of Elektor Magazine 2014 describes the circuit in detail.