Rear Fiber Optics

Materials List

Adafruit Parts Used

Additional Parts Used

  • Clear 1" and 3/4" heat shrink
  • 1/8" Adhesive heat shrink
  • 18" long 3/4" polycarbonate tube
  • 5 1/2' long 1/2" polycarbonate tube
  • Fiber optics & light pipe in varying sizes, at least 6' long
  • Gaffer's tape
  • Hot Glue

You'll also need a soldering iron & accessories, some ordinary heat shrink, and a heat gun.

The Vision

I want to mount something tall and striking to the back of the bike so I can be seen from a distance (and for ease of finding my bike among the crowd). This should be:

  • Bright and tall -- maybe around 6-7 feet high
  • Add motion when I ride
  • Maybe create shade? A parasol attachment? Though this might be problematic with wind
  • Removable, for bike transport

My first idea was to buy a rear bike rack and figure out how to use that as the mount for my "flag".  I bought one from Amazon (yes, okay, I bought the cheap one) and it absolutely didn't fit. The screws were the wrong length and the wrong width, the metal bars weren't nearly long enough, and the stabilizer mount simply wouldn't fit at all. After a frustrating morning, I've scrapped that idea and am trying something a little different. 

I went to the plastic store and picked up a couple of acrylic tubes that fit nicely inside each other. My idea is to create a fiber optic system, with bright lights mounted permanently to the bike, with the actual fiber optics removable for transport. This way I'll be able to add interest up high without having to string long wires or use connectors, which could break or allow corrosion into my system.

After prototyping, I realized my mistake: acrylic is the WRONG material. It's cheap and easy to work with but it's extremely brittle. My bike fell gently down against the wall and it cracked and broke. Back to the plastic store for Polycarbonate tubing! It's much sturdier.

For fiber optics, I want something that will shine screamingly bright. We're just using one LED, so I don't need anything that does fancy animations. A 3W RGB LED will work perfectly for this project.  3 watts is a LOT of brightness! (Do not shine into remaining eye...) 

I'm going to make the fiber optic "tail feathers" a separate system entirely from the rest of the lights on the bike. 3W LEDs draw a lot of power, so I want to give them their own battery pack and controller. I like the idea of two totally separate systems, so if one system breaks or runs out of juice, I've still got another light system on my bike, and all is not lost.

My idea is to mount the 3W LED and microcontroller to the bottom of the outer 3/4" tube, then mount the whole assembly to the bike. The smaller tube will contain the fiber optics, and will simply slip into the larger tube when I'm ready to ride. This way I will be able to very easily disconnect the large tangly delicate fibers and put them INSIDE my car while the bike rides on the bike rack on the OUTSIDE of my car.

This guide was first published on Jun 18, 2019. It was last updated on Jun 18, 2019. This page (Rear Fiber Optics) was last updated on Dec 05, 2019.