Nerf Modulus LED NeoPixel Barrel

I'm sharing my current LED / Arduino / Neopixel Nerf Barrel project while it's still in process. The 3D printed barrel is quite usable as-is, and fits any modulus / stryfe barrel.

You will see the design is complete and I have prototyped it to get it working, however a couple damaged neopixels is causing me some assembly rework. I decided to publish before I loose steam.

The bill of materials beyond the 3D printed barrel is below:
1x round (18.3mm hole) rocker switch
1x arduino pro mini or equivalent (5v logic version)
1x 470ohm resistor
1x 10microF capacitor
13x 5mm X 5mm surface mount neopixels
1x 9v battery
1x 5vdc regulator