One Man Electrical Parade Halloween Costume

Step 4 Prepare the base for the LED matrix

In Illustrator, I made a template to mark out all of the holes that I'll need to drill to mount each ball. The balls I ordered were 38mm in diameter. Apparently, in 2000 it was decided that the "official" size of a ping pong ball would increase from 38mm to 40mm. It doesn't matter whick size you choose, as long as you know what you've got. In my template, I added an extra 2mm between each ball just to allow some room for error when mounting the balls.

I needed a firm base which would be large enough for the matrix so I went a local Target to see what I could find. I ended up getting a black plastic drain board. As you can see from the image, the size worked pretty well.

Since I only had 8.5" x 11" paper I prined 4 copies of the PDF template and taped them together and then taped them on the board. At first, I used a sharp nail to poke a small indentation in the board to guide my drilling, but that was kind of a bad plan. The plastic actually shattered a bit in a few spots. Oh well, nothing a little hot glue couldn't fix. Next time I'd probably just drill the holes through the template and skip the nail. For the holes in the board, I used a 5/32 bit which was wide enough for the leads of the LEDs to fit through without bending. I applied more hot glue to the base of each LED and then pushed it into place. For good measure, I squirted more hot glue into the holes on the underside of the board. I really didn't want any of the balls to pop off.