|
|
Posted by Richard Crowley on 03/06/06 05:37
gojlt2 wrote ...
>A church uses the Videonics MXPro video switcher. Three Sony cameras
> are connected to the MXPro via S-video cable. One camera is located
> next to the MXPro. The other two cameras are several feet away, maybe
> about 50 feet or more. Inexpensive Radio Shack two-way radios with
> headsets are used for communication between the camera operators and
> the director.
>
> Sometimes a camera operator cannot remember which camera is "live". Is
> there any way to connect LED's to the MXPro via a dedicated cable so
> the remote cameras can have a visual indication of the camera that is
> "live"? I can wire 3 LED's at each camera position to correspond with
> each camera position so each remote camera can see instantly which
> camera is "live", but I need an output from the MXPro, either a dry
> relay contact, or a switched 5v/12v DC output at 100ma. I don't see
> either of these options on the MXPro.
>
> Would someone recommend a method to accomplish this task?
We added tally lights to a Videonics MX-1 (likely the predecessor
of your MXPro). On the MX-1 there were four LEDs on the panel
which indicated which input/camera was "hot" and the blinking
LED showed which one was "next". We rigged up a trivial circuit
with an LM339 quad comparator. We looked at the LED signals
with an oscilloscope and discovered that they were "multiplexed"
so they were not continuous DC, but were high-frequency switched
AC. We used a simple passive integrator (i.e. a resistor and a
capacitor) to make DC outputs from the LM339.
You can use the LM339 outputs to directly drive LED tally lights
at the camera locations via cheap 2-conductor unshelded wire.
We used the really thin/tiny "speaker wire" from the Rat Shack.
RS also used to sell giant (1/2 inch) red LEDs for nice big tally
lights at the camera end.
After less than 5-6 productions using the MX-1 we gave up and
bought real cameras (with CCUs) and switcher because the cheap
Videonics thing had such bad artifacts. It drove us crazy.
We also gave up on the 49MHz FRS walkies for camera operator
communication and built our own Clearcom clones. I have
published my information online, including a source of PC
boards if you wish to build your own....
http://www.rcrowley.com/ComClone/default.htm
Navigation:
[Reply to this message]
|