In article .net,
DaveC wrote:

Hello,
I want to use the XC18A wireless video camera in a stand-alone mode without a
controller (for the camera to be on when power is supplied to it). I presume
that I must figure out how the X10 controller turns on the camera, and then
permanently enable the camera. Therefore, I need to know something about how
the electronics inside the XC18A wireless camera work.

The camera section (everything from the female end of its power cable)
is *COMPLETELY* ignorant about anything having to do with the X-10
system - It only needs a 6-12 volt input to operate in "always on" mode.

The camera must be turned on remotely by some X10 controller over the mains
wiring.

Incorrect. The camera section is always on. The X-10 signal only
controls whether the wall-wart sends power to the camera section or not.

On the camera's power supply there are switches ("Unit" and "House")
which uniquely identify the camera.

Actually, the house and unit switches uniquely identify the wall-wart,
not the camera. If desired, you could "rabbit" the end of the wall-wart
wire and feed however many cameras you cared to from one wall-wart
(within the limits of the wart's output capability) although that would
make a mess of your picture unless each camera was running on a separate
channel. (four available, access to that setting is through the little
rubber plug next to the pivot-arm that holds the lens head on the base
of the camera unit - a similar switch is located on the bottom of the
reciever/base unit that you plug into your VCR/Computer/TV/whatever it
is you're using to view what the camera is showing.)

When the controller contacts the camera
power supply, what "turns on" in the camera electronics?

Nothing. The controller signal does nothing but tell the wall-wart to
start sending power to whatever it's connected to. The camera itself is
always on, and doesn't have the first clue what "X-10" is - Its on/off
state is determined by whether it has power applied or not. The source
of that power is irrelevant, and could be the supplied X-10 wall-wart, a
battery pack made up of 10 D cells wired in series, an adapter cable
from a car battery, the +12V output of a computer power supply, or
whatever else is handy and provides 12 volts.

(actually, only about 6 volts are needed to power up the camera section
- The first thing the juice encounters as it enters the camera is a 7805
regulator that knocks the 12 volts down to the 5 volts the camera
actually runs on, and dumps the "extra" 7 volts as heat, so any power
supply that can give you about 6-12 volts at the proper amperage will
work just fine)

The cable going from the supply "brick" to the camera has 3 conductors: 12v,
ground, and another conductor. Does this third conductor get 12v when the
"on" signal is received? 5v?

Third conductor is unused. No idea why they wasted the extra money on
the stereo (tip/ring/sleeve) jack/plug when a cheaper mono (tip and
sleeve only) jack/plug would have worked exactly the same, but they did.

If I had a controller to turn on the camera, I could answer my own question,
but I don't.

Thanks,

No controller? No problem - Pull the wall-wart out of the wall, then
plug it back in. They default to "on", and remain that way until they
receive an X-10 "off" signal. If you're seeing +12v on the end of the
wall-wart's wire, it's already on.

--
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