January 4, 2016
In 2015, I built a new Pixabulb megatree, but didn’t have time to build a topper for it. That is going to get built this year.

Since the meagtree is a 360-degree tree, the concept for this topper is a 3D prop, sometimes called a starburst, sometimes called a porcupine.

I used the same 2″ tubing with 1 3/4″ sleeve tubing that I built the megatree center pole out of. This will let me attach it easily to the top of the megatree. The hub is 8″ long. Then I cut eight 6″ pieces of 3/16″ x 2″ flat stock and drilled 2 holes in each. I welded one of the flat pieces to a side of the 2″ tubing and one of the flat pieces on each of the corners of the tubing. This gave me a place to mount the leaves of the starburst. pic here

Then I cut eight more pieces of 6″ pieces of 3/16″ x 2″ flat stock and drilled 2 holes in each to match the holes in the hub. Next I took four 1/2″ x 40″ square steel tubing from Metals Supermarket and drilled 25 11/64″ holes in each. The first hole is 2″ from the end, and the rest of the holes were spaced at 1 1/2″. Then I welded the square tubes on the flats. The tubes are at 45 degree angles from each other, and the top-most and bottom-most rods are 22.5 degrees from vertical. Once all eight of these were done, I cleaned, primered and painted everything flat black.

Here is one of the leaves and the jig I used to weld them.

I am going to use regular bullet pixels with 4″ spacing for the lights. I found some vinyl-coated 1/2″ EMT clamps at Grainger. These hold the bullet noes in place perfectly.

To bolt the clamps to the square tubing, I purchased 1″ #8 truss-head bolts, lock washers and nuts from bolt depot. I needed 800 of each of these. Here are the clamps mounted to the square tubing.

Now for the lights. I wired each leaf individually so that is will be easier to install and make repairs if I need to. This means I need 8 controller ports to run this. I will figure out that part later.

I first took a 100-count set of pixels and cut into four pieces of 25 pixels each.

I use 18 gauge red, black and green wire from Amazon. These are the standard wire colors I use for all my props. I built the wiring harness so that each length of 25 pixels is power-injected from the center. This way I only have to run one wire for the data line from the end of each string back to the center.

Next I soldered the power and ground lines from the wiring harness to the four sections of lights. I also soldered a length of green wire to the input side of the top three sections of lights. I mounted the first light of each section in it’s clamp to get the lengths right.

One string attached

Two strings attached

Three strings attached

Four strings attached

Next it was time to install the lights in the clamps. I wrapped the excess wire between the lights around the tubing to help hide it. Then I ran the soldered green wires through the wire loops and soldered on the data return lines to the end of the first three sets. Hopefully this will help minimize the light blockage from the wiring.

Here is the completely assembled tree in my living room. It is about seven feet in diameter.

My first attempt a modeling this is to set it up as a 32 string by 25 bulb matrix.

Here are a few videos of effects that seem to work ok on it.