Ever want a string of Christmas lights made with RGB LEDs, so all the lights could change colors? Or with their own microcontrollers, so each could act autonomously? Hell, why not go all the way, and network them while you're at it?

I did.

The full gory details are at TreeGee.com (or will be in a day or two... I just registered the domain name yesterday, so it might not work for another day or two) but here's the short version: for the past 4 years, I've burned most of my Decembers, Novembers, and increasing chunks of October working on this project. This year, for the first time, they look like "normal" LED Christmas lights (I bought a few sets of clear LED lights on sale at Lowe's & removed the plastic diffusers from them to use on my own lights), and the controller I built last year finally works properly & reliably communicates with the lights.

Each light module has its own Atmel ATtiny25 microcontroller, linear power supply, RGB LED, and passive components. The whole thing is wired in parallel with just 3 wires... +12v, ground, and communication. One of my specific design goals was to keep the wires thin (AWG22 or smaller), which required higher supply voltage and individual power supplies for each module (not really a big deal... the regulator chip and 2 capacitors added about 50c to the cost of each light, and completely eliminated my original power problems).

The result? My favorite version of "Feliz Navidad" (originally performed by Home Grown), accompanied by what's arguably one of the most sophisticated (and expensive) strings of Christmas lights in the world.

How expensive? I don't know. I've lost count. If you assume my time is valueless, and you ignore the cost of the tools I've bought, the parts I've destroyed, and the crate of non-working light modules (roughly 3 or 4 for every working one that you see on the tree here), each light module has about $4 worth of parts (bought in hundred quantities from DigiKey and Futurlec). There are 36 on the tree today. Do the math. Then forget it, because it's too cool to care how expensive it was.

Note: the lights begin by pretending to be oldschool blinking lights from the 1980s, rapidly evolving into more sophisticated fading lights from the 1990s before showing their very-21st-century "true colors".

Check back around New Year's for a better version of this video. I ran out of time, and had to go with what I had done by mid-afternoon on Christmas Eve. I didn't even have time to properly re-encode it with the source music, so you'll have to just make do with the audio recorded with the microphone in the room (yeah, it's bad). Also, I need to re-shoot it with a better camcorder. I used an Aiptek ActionHD bought from Wal Mart this morning, then discovered (too late) that its autofocus is worse than useless... it's bad, and can't be disabled. So, I'll probably be returning it on Friday, and buying the one that's technically one model lower (720p60 vs 720p60+1080p30, and fixed-focus lens). Think of this video as the 0.9 beta version, released prematurely to meet a holiday deadline, with bugfixes coming next week ;-)

Oh, and Merry Christmas!