[sdiy] Magnetic field

[john mahoney]

----- Original Message ----- 
From: "Ian Fritz" <ijfritz at earthlink.net>
>
> The advantage of magnetic is that you don't have to wire up the source.
:-)

Huh? I don't see the difference.

Whether the switches are optical, electromechanical, or magnetic, don't you
have (a) a signal and (b) a destination for that signal? Or, am I (as often
happens ;-) missing something basic?
--
john