Luckily I have access to a laser cutter, so I knew I would be using it to make these. You won't need your own laser cutter. You can either send it out to be cut by a company that does laser cutting, or you can go the manual route and print the PDF and lay it out on the cardboard and cut it by hand.

The base is made from 1/8" cardboard sheets purchased from the local art/hobby store. Our laser cutter has a 32"x18" bed so I had them cut the sheets down to that size.

Panel

The panel is made up of a few main parts: the base, the slats, the cover, and the strap. The base holds the LEDs, the slate provide the pixels and overall stability of the panel, the cover diffuses the light, and the strap makes it portable.

Modeling

To make the files for the laser cutter I modeled the base using Rhino. I modeled the all the parts of the panel very accurately in an effort to let the laser cutter do as much work as possible.

I made each panel so that each vertical and horizontal fin would slide into each other and they would notch also into the base. Setting it up this way allows the parts of the panel to slide and notch together without the need for much glue, while also ensuring we would get perfect squares for the pixels.

Notes:

The notches and joints have a 1/64" clearance on both sides to let the cardboard slide together nicely. The slots end up being 5/32" wide (1/8" + 1/64" + 1/64").

I have added the 3d model in DWG format to the files for those interested.

Laser Cutting

As mentioned before our laser cutter is 32"x18" so the CAD files I made to do the laser cutting are set on that size. I have added the .dwg file for the Ghost costume. You can use it to laser cut your own, or you can print it out and use it as a template to hand cut the cardboard.

If you are going to do it by hand you can easily lay this out and cut strips of cardboard. You can could measure it out yourself, the pixels are about 1.5" square and 2" deep with a 12mm hole in the middle for the LEDs. You can also use the provided PDF as a template for cutting.

Notes:

We used 12mm LEDs and that's what size the holes are. The LEDs went in nicely, but since it is cardboard they got a little loose, especially if I had to take the LEDs out and put them back in. If I were to redo it I would make those holes slightly smaller.

Assembly

The base had to be cut in two pieces since our laser cutter bed's small dimension is 18", which is smaller than the 22" x 22" dimension of the base. I used good ole duct tape at the join to keep it together initially. This is really to keep it in place while adding the LEDs and slats. Once the slats were added to the base they provided the real support and stability.

Each slat is labeled by scoring either "H#" or "V#" for Horizontal (H) and Vertical (V) and which number (#) in order. The slats slide together nicely since we added additional 1/32" clearance. My first tests left a lot less room where they slid together and made it impossible to put it all together. Once the were all slid together we put the slats on the base. They notched in where the plus sign shaped holes in the base are. Once it was on the base I duct taped the slats to the base on the ends. Then I added a small bead of hot glue the top left corner where the slats meet to keep them in place and ensure they wouldn't slip.

The notches for the slats extend through the base so there is a small tab on the back of the base. I also added a bead of hot glue to these tabs to keep the slats securely on the base.

After thought

As you can see in the 3d model diagram I did not plan for an enclosure on the back of the panel. This was a mistake! I noticed this a couple of hours before tick-or-treating and I hastily cut 2.5" cardboard strips and added them to the back of the panel. to give something other than the LED wires to rest against the body.

This helped, but really it should have been fully enclosed. When walking around with the panels with the back open the LEDs tend to get pushed in. You can see in some of the pictures where the pixels are no longer really pixels, but point lights. This is where the LEDs were pushed or fell in. I stopped the family a few times to fix these over the night or tick-or-treating.

Note:

If you are going to make these, plan for a back panel to enclose the LEDs. Don't make the same mistake.