I want to be able to remotely douse a pair of small LCD computer projectors. I don't have one of those projector dousers and there is not really a budget to rent a pair for this show. I do have a couple extra SmartColor Pros that I can use. Is there a way for me to make a custom scroll with one frame of clear and then some sort of opaque material for the second frame. I can probably figure out some sort of mounting device to hold the scroller in front of the projector.
Dousing a Projector with a Scroller
- Thread startermetti
- Start date
Metti-
Are you able to construct a string consisting of a single wide frame of clear and a single wide frame of Mylar? (Sheets and short rolls of Mylar are easily found at Hobby Lobby or other local craft shop.) Tape your custom string onto the existing take-up reels located within the scroller.
Knowing the scroller really wants to 'read' the total string length of 16 frames- you may still be able to get by on the cheap by setting a command of 5% for your clear frame and a command of 95% for your Mylar frame...
Are you able to construct a string consisting of a single wide frame of clear and a single wide frame of Mylar? (Sheets and short rolls of Mylar are easily found at Hobby Lobby or other local craft shop.) Tape your custom string onto the existing take-up reels located within the scroller.
Knowing the scroller really wants to 'read' the total string length of 16 frames- you may still be able to get by on the cheap by setting a command of 5% for your clear frame and a command of 95% for your Mylar frame...
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There's no harm in using a short scroll. The first thing scrollers do is figure out how long the string is.
I did the mylar thing but had the scroll rip apart because the tape didn't bind well to the mylar. I redid it with an R26 gel and found it blocked most of the visible light. An R382 would probably work better but I needed the red for our low-light camera.
I did the mylar thing but had the scroll rip apart because the tape didn't bind well to the mylar. I redid it with an R26 gel and found it blocked most of the visible light. An R382 would probably work better but I needed the red for our low-light camera.
MPowers
Well-Known Member
Talk about re-inventing the wheel. When I was in grad school, we had a multimedia production that needed to douse several projectors, 20, in tight sequence for a total of 5,000 slides during the performance, Yeah, I said "SLIDES", you know, those celluloid things with a cardboard or plastic frame.... 'bout 2"x 2 1/4"??? Now, because this was in the Jurassic period, the projectors were Kodak Carousels, rotating tray, 80 slides each. Our problem was that no projector could change slides fast enough for the scenes and the available technology at the time could only fade or change from one projector to another on the same screen, in about 1.5 seconds. No such thing as "click - click - click". So we build a dedicated, analogue, computer. It could only do one job, run only one program, "The Slide Show"! The next thing we developed was the douser. A rotary solenoid with a 1/4" rod attached. The rod had two sheet metal "vanes" braised on at 60 degrees apart. The Carousels were stacked with the lenses as close as possible and the rod ran up and the vanes were in front of each lens in turn as the solenoid rotated the rod. each projector changed it's slide while the douser was in front of the lens. Thus the change on the screen when the solenoid flipped, was instant, no fade up or down or dark time while the next slide dropped. The "computer" control was one button, every push and the program advanced a step. Ten Screens, ten solenoids, twenty projectors, 5000 slides. It took us, roughly 6 grad students, 2 faculty, about 8 months to work it out and construct. Some time in the future I'll tell you how we made slides in the days before computers and photo shop and digital photography.
I'm well aware that there are superior, existing ways to do this. I have worked with the City Theatrical dousers many times but this show has a tiny budget and I already own the scrollers. I am just trying to work with what I have.
In the past, I've rigged up a simple system with tie line, pulleys and small hinged pieces of wood or hung pieces of fabric. With some scrap lumber and less than an hour, you could get a pretty simple system set up that avoids custom gel strings. Of course this system is not dmx controlled (unless you want to go through the fun of hooking it up to a dmx relay with a few more steps), but it's effective.
Could this be what you're looking for?
http://www.controlbooth.com/forums/multimedia-projection-show-control/6801-need-remote-douser.html
MPowers
Well-Known Member
Metti,
Didn't mean to disparage your efforts, merely remarking on the fact that after forty years we (theatre technicians) are still trying to achieve some of the same things. I was also poking fun at the somewhat caveman technology and tactics we went through to get to the end result. Today, with computers and the other technology available, one or two people with 4 weeks time could easily duplicate our months of effort. In addition, their program would be changeable and adjustable with a few moments and a little keyboard data entry. With the system I described, any change would mean hours of un-soldering connections on rotary switches, re-wiring and re soldering for each step. Each step change would cascade down each succeeding step until a check point was reached and each step in the cascade would need the same reworking. A check point was an intentional "end point step" inserted every so often, so that everything from that point on started new and earlier changes did not affect them. If there had been such things as DMX and scrollers then, we might well have used that method and saved our selves a lot of time and effort.
Didn't mean to disparage your efforts, merely remarking on the fact that after forty years we (theatre technicians) are still trying to achieve some of the same things. I was also poking fun at the somewhat caveman technology and tactics we went through to get to the end result. Today, with computers and the other technology available, one or two people with 4 weeks time could easily duplicate our months of effort. In addition, their program would be changeable and adjustable with a few moments and a little keyboard data entry. With the system I described, any change would mean hours of un-soldering connections on rotary switches, re-wiring and re soldering for each step. Each step change would cascade down each succeeding step until a check point was reached and each step in the cascade would need the same reworking. A check point was an intentional "end point step" inserted every so often, so that everything from that point on started new and earlier changes did not affect them. If there had been such things as DMX and scrollers then, we might well have used that method and saved our selves a lot of time and effort.
I built several projector dousers, using Northlight DMX to servo circuit boards. I thought that we had thee ultimate douser. After reading the various posts on the using a CD drive for a douser, I made one of those little guys. It quickly became our first choice.
The primary reason for it's popularity is that it can be controlled by the person that is running the visual program on a computer or DVD player. When using the DMX controlled douser, the light cues or lighting board operator had to control the douser. In almost all of our productions, the program on the projector is conrolled backstage at the Assistant Stage Manager's podium, while the lighting board is in the booth. After loaning our CD tray douser to several other theatres, I ended up building quite a few more for those theatres, and several more for our theatre, for when we do multiple projections.
The DMX to servo boards ended up being removed from their dousers and being used insted to build DMX controlled irises.
Tom Johnson
Florida's Most Honored Community Theatre
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