From Trammell Hudson's Projects
Fiber Optic LED fascinators
Holly shows how to turn a bundle of fiber optics into a wearable LED fascinator. She is teaching a class at NYCR on wearable electronics, too!
Cut the bundle and square up one end.
Cut enough heat shrink to cover the LED and a cm of the fiber optics.
Temporarily secure the bundle together with tape that doesn't leave a residue, like Kapton tape or Scotch tape. It is easiest to slip the heat shrink over the bundle from this end, but be sure that it is far enough away from the end for the next step.
Flatten the bundle and LIGHTLY apply hot glue, keeping the tip of the glue gun well away from the fibers to keep them from melting.
Squeeze into a tight bundle to secure it. Be careful not to squeeze it onto your fingers, or smear it over the ends of the fiber.
Once the glue has cooled, slide the heat shrink over the glued end of bundle and insert the LED so it is completely inside the heat shrink and it will be locked in after shrinking.
Use a heat gun to secure the LED. Be careful not to hold the fibers over the heat for too long because they can easily melt and bend.
Squeeze the legs of the LED on a coin cell and you should have a fun constellation of bright points at the end. Color changing LEDs are fun, too.