Engineering masquerading as art installation masquerading as Christmas lights

About this time last year, I was watching Star Trek - Generations, - the part where Picard is caught in the Nexus and he's looking at the Christmas tree. There are these glass balls on the tree that light up with little slow motion light explosions inside.

And that made me want to make some. So, over the past year, with some input from CR4 members, I made a set.

Here's how they look, hanging from my oak tree:

Here's a video I made of them at night:

http://www.youtube.com/watch?v=O2V5ekXMxjU

There are 17 balls. Each ball is soccer ball to basketball sized, hand blown colored glass, that I picked up at Hobby Lobby. Each ball contains a circuit board that drives a xenon lamp and is connected to my 12V outdoor light power.

The circuit contains a PIC microcontroller that drives a MOSFET to pulse width modulate the lamp. Controllable variables are initial delay, rise/fall time, on time, and off time. There are 336 different combinations of these variables in a sequence that lasts about 1 1/2 hours. The balls come on in sequence, over about three minutes, then execute the series of 336 combinations, and then repeat. The effect looks somewhat random, but it's actually not, each timing instance moves from ball to ball. But the movement is so slow that the pattern is only subconsciously felt, if at all.

The full details are documented in my Live Journal blog, which you can access at

http://artkouros.livejournal.com/tag/next+big+christmas+thing

Anyway - that's how I spent my summer.