The actual candle pictured here - before being burnt - is a "large" Woodwick candle. That's not the container I'm actually using, but I don't have any more "medium" candles lying around.

This seemed like a fun thing to build; I have no particular purpose for it, but I have a bunch of WS2812 (and 2812b) LEDs lying around. So one night, I rummaged around our house looking for something that could support these LEDs inside said container.

The closest cylinder I found was a baking soda container, whose diameter was just a hair too large. So I emptied it out, sliced it down the side, and - you can just see this in the picture with the solder side of the LEDs - glued it together so it would be a bit smaller (E6000 glue, if you really care). Then I spraypainted it black, waited for it to dry, and cut up the strips of LEDs to the right length.

The LEDs are hot-melt-glued on to the cylinder. Now, I know these LEDs are going to throw off a lot of heat and hot melt glue probably won't be the best choice, but at this point, I have some serious questions about whether or not this is going to work. I figured that the soldered wires would be a fine mechanical restraint, at least to get some bearing on the project. And so far, that's been true.

The control circuitry, then.

I've done a bit of WS2812 controlling. For the past two years, we've used them as ad-hoc Christmas tree lights, with some nice patterns and colors that we all enjoy - driven by an OctoWS2812 coupled with a Moteino, so that we can wirelessly control the light patterns. This year, my son set up a small tree in his room too and wanted more lights: so we set up a small strand of WS2812s driven by another Moteino. So I have some history and - dare I say it? - infrastructure to support these.

I figured I wanted to build this out of junk parts, so I didn't really want to go buy another Teensy and OctoWS2812. I have a bunch of Moteinos, and some Pro Minis, so I thought it would be sufficient to drive this thing from a Pro Mini and communicate over RF with the Moteino. (I assumed, right or wrong, that a single Moteino would be underpowered for high-speed display changes, and I still had no idea what I wanted to do with the final display, so two microcontrollers made some sense.)

All of this, generally speaking, worked fine. It was December and we're some combination of crazy and cheap; our house runs about 62 degrees Fahrenheit. This thing puts off a bunch of heat, but not so much that it seems a problem. Particularly when the lights aren't on full bright and constant. I orient the candle so the wood top is now the bottom, jam all the parts inside, and it looks pretty good.

And then I set it up on a window where the sun shone in.

The candle, of course, acts like a greenhouse. There's no airflow through this thing. And the WS2812s do, as I had at this point forgotten to deal with, put off a good bit of heat. So when they hit something like 230 degrees F, they began to fail. Bringing me to remember about heat load and dissipation. Riiiight.

But the point is proven. I like how it looks, and I figure it's just a matter of dealing with the heat load - a couple holes and a fan, replace some dead pixels, and I should be golden. Boy, was I wrong...