I made a geeky version of this using an industrial stack light, an Arduino, some MOSFETs, an RFID card reader, and node.js. Pictures: http://imgur.com/a/dX33N

I made a geeky version of this using an industrial stack light, an Arduino, some MOSFETs, an RFID card reader, and node.js. Pictures: http://imgur.com/a/dX33N http://imgur.com/a/dX33N Videos: https://www.youtube.com/watch?v=bButG4EWSfE https://www.youtube.com/watch?v=bButG4EWSfE https://www.youtube.com/watch?v=FQK0fW6-7jA https://www.youtube.com/watch?v=FQK0fW6-7jA As my desk is in the far back corner of the office, and the light is visible from anywhere in the room, people know if I'm heads-down on something, away from my desk, or available for interruptions without having to come over and potentially interrupt me by asking. I can change the light by scanning my building ID card or using a web interface. Note that this was done as an experiment to learn a bit about electronics, and a bit of an evolving joke to see how much random technology I can cram into a project. While I may be socially immature, I'm not as bad as "YOU CAN'T TALK TO ME WHEN THE RED LIGHT IS ON". I think it is useful, nevertheless, as an ambient cue when I am really trying to focus on a problem.