Hi all. I have a bit of a design challenge I'm grappling with. Here's
the deal. I have a friend who wants to make some remote indicator
lights. In the beginning they will be controlled by switches, but I
will be building a PIC based system in the future.

We've talked about how to deal with long cable runs in the past, but
this application is slightly unique in that the indicators are
bi-colour LEDs. These are the ones where they are two diodes wired
back to back. At the moment I'd like to avoid having to put in a
remote PIC mainly due to the tight delivery schedule he needs. So how
best to provide protection when the polarity of the line will be
changing? Let's guess that the line length will be between 50 and 400
feet of cat5 cable.

Also, I haven't done the calculations yet for voltage drop. If anyone
has done this in the past, tips on good voltage to use (to deal with
line drop) would be appreciated. In the future I will be moving to a
more solid state design and I'm thinking about using an open collector
or similar driver with a slightly higher voltage to drive the long
line.

Thanks!

Josh
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