When in the state of Flow, creative people usually don't want to take a break for mortal considerations like eating or bathroom breaks. The great Beethoven famously kept a chamber pot under his piano, so as not to lose momentum in a fit of genius.
This applies for creative people who are not up there in the rare air of the Immortals, too, like people in the workshop at the Bloomington, IN, Makerspace, Bloominglabs. It is far enough from the bathroom that one would have to take a walk into the other room, perhaps to find it occupied, which would only mean further delay.
This gave me the idea for an eye-catching indicator light in the workshop. Why a light? There are lots of power tools in the workshop that make a lot of noise. Just as radio studios have flashing lights to indicate a doorbell ring or incoming call, it would make sense to use a light for this. This could then be expanded for other usage (including a 'doorbell is ringing' indicator, or you could set alarms if you need to be somewhere, or you could be notified somebody just badged in). But before going crazy, we built something with a defined purpose and scope.
Bloominglabs recently hosted Spark.io build nights thanks to Spark.io and Instructables. Without sounding like a salesman (hopefully), I was happy to get my hands on some Spark Cores to play with. I've long been interested in using wireless sensors for projects, but solutions were expensive, or cheap but slow and not necessarily reliable (433 MHz transmitter/receiver pairs), or hard to use. The Spark Core (and soon, the Photon) seemed to address all these issues, plus Spark.io provides an interesting cloud infrastructure I wanted to play with. So this was my chance to get my hands on some.