Projector Shutter

wfor

Member
I know City Theatrical sells those fancy DMX shutters that turn Video Black to actual black, but they're a wee but expensive.

But its a pretty simple system I think I can work out on my own. I'm even open to a mechanical system (like pulling ropes).

The projector is fairly large, (bigger than your average, but not a Christie or anything, just InFocus). It is on a ceiling mount on a 10 foot or so ceiling, about 10 feet from the lighting desk.

I've considered motors, this is cumbersome. Steppers would be too complex, and some sort of actuator is too slow.

I think I can work something up, just wondering if anyone else has taken on a similar project.
 
The CD ROM is ingenious, however- for my applications- a bit difficut to mount. However- it did give me a pretty ingenious (I think, at least) idea. I'll post a diagram up soon.

A disc or cardboard or matte board (something lightweight) It is circular, more than twice the size of the apeture. It has an opening like a "D" filling half the circle. The motor, mounted on top, spins the circle until it is stopped by a pin getting caught inside the "D". Its a sort of ghetto rigged limit switch. I think I have a motor that runs on 120 volts! slow... but I don't need it to make visible cuts, just to prevent that "dead tv" look right in the middle of a beautiful black out. Or even worse, the computer blue screening or something... lovely.
 
Here's a crude diagram made in sketch up-
 

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A disc or cardboard or matte board (something lightweight) It is circular, more than twice the size of the apeture.

Just be careful of the material you use. While the heat of the light output might not be enough to actually ignite any material, you still might be suprised at just how hot the light can be. I have seen many a lens cap melted almost all the way through (either negligence or intentially leaving it on) and have seen some nice char marks on the back of notepads leaned up against a projector to block the light. Since we should always be using all of our senses in a performance space, why introduce a burning smell that could make you ignore something else?
 
My school recently started heavily using projectors in our shows and the best way that we have found to get actual black is a ColorSource color scroller with a clear to black gradient color media scroll mounted on the projector. It allows for a fade out or a blackout and it is controlled through DMX, if you are unfamiliar with color scrollers.
 
Just be careful of the material you use. While the heat of the light output might not be enough to actually ignite any material, you still might be suprised at just how hot the light can be. I have seen many a lens cap melted almost all the way through (either negligence or intentially leaving it on) and have seen some nice char marks on the back of notepads leaned up against a projector to block the light. Since we should always be using all of our senses in a performance space, why introduce a burning smell that could make you ignore something else?

Yes, they certainly do burn through notebooks :) Thoroughly Modern Millie we were doing subtitles, we had a folder or something in front of the projector during rehearsal and it actually burned through the thing. Quite terrifying. I don't remember what we actually used for the production. But yeah, make sure you use something that will not be burned through!
 
Hmm, a point I didn't consider. I'll probably use matte board with a foil backing, or perhaps some tin. Any objections to this?

Color scrollers are out of the questions here, unfortunately. I wish I had one at all.
 
Hmm, a point I didn't consider. I'll probably use matte board with a foil backing, or perhaps some tin. Any objections to this?

I'd still stay away from the matte board, even with the foil. You could try the "do it yourself gobo," which is a heavy duty pie tin that you cut out in your shape. If so, you could probably use the spray paint used for charcoal grills to give it a black matte finish.
 
How are safely securing the scroller to the projector, those of you suggesting that route?
I have used a Wybron Eclipse II douser in front of my projector which is supported on a separate support from the projector itself. When I was doing AV on a regular basis, we had projector cages from Display Devices instead of standard plate mount (it was easier for flying stacked projectors) which allowed us to put dousers/scrollers right on the cage. I also was able to mount a wireless access point in the cage for projector control.
 

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