I think it's even simpler than you think... AFAIK, the "signal" is simply
a switched circuit, with the IR detection part of it forming the
"switch". I believe current flows when it's receiving the reflected signal
and is stopped when that signal is interrupted. Or I could have that
backwards...
-rf
At 05:33 PM 3/23/2003 -0500, Steven Trovato wrote:
>Hi all. Does anyone know how a garage door safety reversing system works,
>from an circuitry perspective? I'm talking about the beam transmitted
>across the opening. There are two screw terminals on the opener for these
>components. The IR transmitter and receiver components each have two
>wires. One from each goes to each screw terminal. One is obviously
>supplying power and the other is obviously a common ground. There is no
>separate "signal" wire to indicate that the beam is obstructed or
>clear. This must be superimposed over the existing two wires
>somehow. Anyone know how? The particular unit in question is a Sears
>(Chamberlain), but I'm sure others are similar. Thanks.
>
>-Steve Trovato
>trovato@computer.net
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