I’d like my Pixelblaze LED project to be portable. A quick math session has determined while the maximum possible power draw is quite high, a battery powered design should be possible in a more realistic scenario. With that concern settled, the next decision is on choosing a physical shape for this light show.

I want a three dimensional shape because I wanted to play with a cool feature in Pixelblaze: the Pixel Mapper. This feature allows me to specify a mapping from pixel order to their physical location. Then I can write my LED pattern in terms of physical position either in 2D (x,y) or 3D (x,y,z) coordinates, and let the Pixel Mapper figure out how individual LEDs will correspond to my pattern. This allows me to decouple a pattern’s logical behavior from a specific rig’s physical layout, allowing fun tricks like creating a pattern works equally well on 300 or 10,000 LEDs, just by changing over to a new mapping in Pixel Mapper. This would be an extremely powerful creative tool if I could get it to work for me!

Backing off from big dreams, I return to my 5 meter spool of 300 LEDs on a single strip. To support projects like mine, these strips were designed to be cut apart and rearranged. Solder pads are exposed so we could electrically connect them back into a single chain, no matter their physical arrangement. This sent me into analysis paralysis for a while trying to decide how to cut them up and how to rearrange them. Eventually I decided to do the easiest thing: I’ll use the strip in a single segment, no cuts.

The most basic way to create a 3D geometry from a single line is to curve it into a helix. In addition to not requiring any cuts or resoldering work, it also avoids sharp bends which these strips have only a limited tolerance for. A cylindrical shape is an easy introduction into the 3D space of pixel mapping, a “Hello World” before I tackle future projects with more sophisticated geometry.

Next step: designing a chassis for my helical LED strip.