[This is my 2nd "catching up" post - I started this project in summer 2009 and am just getting around to documenting it] After finishing my 4 channel light dimmer , I wanted to create a comprehensive room automation system, inspired by fellow MIT student Zack Anderson's MIDAS project. Having just been introduced to the world of Arduino, I chose to use an Arduino as the central microcontroller. In order to make the automation more useful, I hooked the Arduino up my server (a Dell PowerEdge 2500 deskside server I picked up for free on Reuse - MIT's recycling/reuse mailing list) so that I could integrate a web interface and more sophisticated control logic. More on this later. The first step to the automation system hardware was getting all of my lights computer-controlled. I piggy-backed my 4-channel light dimmer to the Arduino's serial pins such that messages from my computer would go to both the light-controller and room-automation Arduinos. Next, I needed a