Arduin Yún is a powerful device combined of regular Arduino (Atmega32u4) and Atheros AR9331 microprocessor running Open WRT based on Linux distribution. This gives Simplicity from Arduino side and flexibility from Linux. It features several powerful peripherals like WiFi, Ethernet, USB Host, MicroSD. This makes ideal solution for internet of things.
David wanted to automate his office where system could control lights, heating and would read couple of sensors. He used Node.js for implementing network server. He had to do several workarounds as Arduino Yún is quite limited on RAM, but several trick did the job. This applies to installing Firmata package which takes care of inputs and outputs of Atmega32u4. Refer to GitHub for more details.