Iduino Yun Shield, an powerful development for Arduino board, is designed to solve the problems of connection and storage which exist in the Arduino board. Iduino Yun Shield runs Open Source OpenWrt System (Same system as runs in Arduino Yun) and it is fully compatible with Arduino IDE V1.5.4 or later versions. Yun Shield is an ideal choice for Arduino Projects which require various internet connections and more storage.
Actually, Iduino Yun Shield is equal to the official Arduino Yun, but Iduino Yun Shield is more flexible because it can work with other Arduino board such as Uno, Duemilanove, and Mega etc. Iduino Yun Shield uses external antenna which provides stable connection under various environments.
The Iduino Yun is the core module of Iduino Yun Shield. And it requires 200mA current when in full load, so it is powered by the Arduino VIN pins to avoid overheated in the Arduino onboard 5V LD0.
The Open Source hardware of Iduino_Yun_Shield: https://github.com/dragino/modules/tree/master/hardware/YunShield
The Open Source code of Iduino_Yun_Shield: https://github.com/dragino/linino
The official web page of Arduino Yun Bridge: http://arduino.cc/en/Reference/YunBridgeLibrary
The official forum of Arduino Yun http://forum.arduino.cc/index.php?board=93.0