LED Light Pipe–Experimentation

During the weekend, I had an idea to make a fun toy for my daughter. The toy is basically a light pipe that transports light from a 20,000 mcd white LED through a bundle of clear nylon filament (fishing line) so that the tips of the filament fluoresce.

This is an incredibly simple project and one that only uses a handful of parts:

• a 5mm 20,000 mcd white LED;
• about a meter of fishing line (I used 20kg clear fishing line);
• 5mm heat shrink tubing (mine was about 10cm in length);
• some electrical tape; and
• 6v battery

The legs of the LED are bent so that they can make contact with the battery terminals. The 5mm shrink tube is slipped over the LED and carefully heated so that only the part in contact with the LED is shrunk (the other end needs to be open so that you can feed the bundle of fishing line in).

Make a loop of fishing line so that the bundle is approximately 5mm in diameter. Stretch the loop out so that it is about 12cm long.

Cut the fishing line loop at both ends so that you end up with a bundle of cut lengths of line.

Feed the fishing line bundle into the open end of the heat shrink tube so that the tube is almost full (you may need more line for this).

Heat the heat shrink tube along it’s length so that it tightly grips the filaments.

Connect the LED to the battery and you have a light-brush. My daughter used the brush outside in the dark (and later in her bedroom) to make light patterns.

The LED is held onto the battery with some electrical tape and I made it so that the negative was not connecting unless it is held tight.

I’m going to make another one of these with a plastic tube to house the battery and with a simple touch terminal on the side so that the LED is lit when the tube is held.

Photographs of this will follow.