[VACList] Re: light guides for porch light

[jon fitz <fitzjo1@xxxxxxxxx>]

As a guy who designs optical fiber cables for a
living, I would use the illuminated switch.

As a guy who loves gadgets, the best ratio of function
to cost I have found for your application is the stuff
they sell for lighting.  They actually sold it at the
local Lowe's for a while, but I guess it didn't take
off.  

Typical systems use a single bright source to "inject"
light into the individual fibers. The fibers are
grouped into small bundles that are covered with a
black plastic jacket.  You can buy the bundles by the
spool.

The operating principle for these fibers--total
internal reflection--depends upon having an interface
in which there is a change in the Index of Refraction
(IOR).  This creates some practical limitations when
using a clear plastic rod.  The IOR of air is much
lower than the plastic and so there is strong
reflection at the rod/air interface.  The hardware
used to mount the rod is another matter and can cause
"leaks."  Similar problems arise if you create tight
bends.  The fiber I mentioned avoids this problem by
putting a second layer of plastic on the core that has
the necessary optical properties. Thus, contact with
other materials won't significantly affect its
performance.  It's also quite flexible. (If you want
to learn about this email me--no sense getting flagged
for boring people about fiber optics! :) )

Many of the expensive bundles you will find actually
have the fibers organized so that they collectively
transmit an intact image from one end to another. 
Others are designed to handle very high optical power
densities.  Neither feature is necessary for your
application.

Jon in SC
68 Overlander