On the camera, there's a hacked-up PoE cable that does the following:
1 wht/org ethernet 2 org/wht ethernet 3 wht/grn ethernet 4 blu/wht GND 5 wht/blu Digital Input + 6 grn/wht ethernet 7 wht/brn Relay Output 8 brn/wht +12V
In the box above the door: Ethernet pins pass through to Ethernet input (into which is plugged the feed from the back of the space.) GND from power input goes to GND from camera, also to LED cathode and SSR negative. +12 from power input goes to +12 from camera, also to switch contact. Relay Output from camera goes to LED anode and SSR positive. Digtal Input + from camera goes to switch contact. SSR isn't currently connected; signals are on orange wires, shrinkwrapped to prevent shorts in the time being.
(To accommodate a future local OPEN sign, provision has been made for connecting the big solid-state relay, which can switch anything we could throw at it.)
Proof-of-concept batch file:
:top del getdi.cgi wget --user=port --password=port http://i3detroit.dyndns.org:5000/cgi-bin/getdi.cgi find "DI=H" <getdi.cgi echo %errorlevel% if %errorlevel% EQU 0 wget --user=port --password=port http://i3detroit.dyndns.org:5000/cgi-bin/setdo.cgi?do=l --output-document=NUL rem This turns the LED off when the switch is down. find "DI=L" <getdi.cgi echo %errorlevel% if %errorlevel% EQU 0 wget --user=port --password=port http://i3detroit.dyndns.org:5000/cgi-bin/setdo.cgi?do=h --output-document=NUL rem This turns the LED on when the switch is up. sleep 1 goto top
The most important part of all this! Camera documentation: