Arduino for the Cloud considers the Arduino Yْn and the Dragino Yْn Shield as components closing the gap between a typical microcontroller application and connection to the cloud. Arduino Yْn combines the classic Arduino with an Atheros AR9331 system-on-a-chip (SoC) for wireless access points and routers platforms, which uses the Linux distribution Linino (OpenWRT) operating system. The Dragino Yun Shield expands any Arduino with network capabilities by the Atheros AR9331.The combination of microcontroller and Linux device supports the whole chain from sensor to software applications in the cloud by hardware and software. This book deals with the Arduino and the Linux device and their interaction, without the need of detailed Linux knowledge.