Make your own scroller and gobo rotators.

[Arez]

Why not? Sure it would take some time to get it perfect, and getting it to be DMX operated wouldn't exactly be easy. But it would beat paying hundreds of dollars per unit. So why not do it?

I'm just brainstorming here, and the CD Drive Projector Dowser got me thinking, why not? The hardest part would really be getting it to be DMX controlled.

Gobo Rotater: Take a gobo put a heat resistant rubber gasket(not sure if that's the right word, but more or less something to shrinkwrap around the gobo to give it friction). The bottom frame would have to bearings to support the gobo, the top could use two motors from a CD Drive, nothing fancy, with the right amount of pressure you could easily make the gobo rotate.

Color Scroller: Tape your selection of gels together, here's where it gets cool, we steal a concept from tanks, you affix a tread system to the outer edges of the "gel string" in parallel and you have two motorized rods one at top and bottom and you would use it like a scroll, and again, a small cheap motor would be more then powerful enough to get you from end to end and anywhere in-between.

I think I might draw something up to better illustrate what I mean in parts, since I'm not an engineer I don't know all the proper terms, but I can draw what I'm talking about.

Either way why not once you get one done the process would be cake, and you only need to do the programming once, the part totals would cost a fraction of the price, and if you had the programming done already you could make 20 in a weekend with a few friends and the promise of a case of beer at the ed of the night. Or you could outfit a venue in a few weeks during season downtime.

Has anyone done something along these lines? I know I'm saying it would be cheaper materials, but the end product wouldn't be cheap, it would be easily reparable, drop one, fix it the next day, just swap out the motor/string/bearing/plates.

Why not? Any ideas, or have I just been drinking too much caffine?


Disclaimer: I am only brainstorming and asking if people have tried something like it, not recommending that you go out and do it without the supervision of someone who knows what they are doing.

[derekleffew]

Moving this thread to the Lighting forum.

In the inimitable words of Cher, (in the '80s during the lowest point in her career while hawking Laurie Davis products on late-night infomercials): "If it came in a bottle, everyone would have a great body..."

This post from the CB Glossary entry: scroller, pretty much sums it up:

From the old fart department: Here is an absolute truth that many of us have learned over a lot of years: Any moron can make one scroller that works. Now show me 100 scrollers that all go to exactly the same place, with the same DMX value, with old and new gelstrings, over a long period of time. That's harder--much harder! Sometimes the cheapest is not always the cheapest!

Ever wonder why the ETC Revolution got a retrofit Wybron scroller more than two years after its introduction? Hmmmm........

(I wish I knew who the "old fart" was who added that, so he could be properly cited.)

By all means, Arez, attempt to build your own scrollers and rotators. They may very well be the best solution; for you. Report back here as to the reliability, dependability, and repeatability of your products. If planning to sell your inventions, make sure you're not infringing on any existing patents or existing or imagined technology. You may find a career with Wybron or GAM.

[dramatech]

Yes, I have thought about it a lot. In fact, I built one pototype. It uses a stepper motor and some comparison opamps. The only problem is that it is analog 0-10vdc. Finding the gears and cogged belts and a pot that doesn't have physical limits makes it difficult to find parts. Of course you could use a DMX to analog converter and run the scrollers out with individual cables, but daisy chaining would be near impossible. I started the project because our community theatre didn't have any scrollers, and with limited space they would be great to increase our flexibility. The project came to a halt a little over a year ago, when I started finding scrollers on ebay and other sources that were damaged. The prices were fantanstic. Having the skills to fabricate a scroller, I also had the skills to repair and rebuild used scrollers. All in all it is easier and more economical for me to just fix/rebuild. Doing just that, I have acquired 26 scrollers todate. Our current show is using all 26.
While there is no question that Wybron is the better known brand and sort of the standard that other scrollers are measured, I only purchase used scrollers that were manufactured by Spectrum engineering in Canada or Camelont in Sweden. Most all of the parts are interchangeable between the two. The early version of both, that are not autocalibrating, are by far the easiest to fix and rebuild, and the parts are usually available from electronic vendors cheaper than from either manufacture.
The Spectrums are sold under several different names such a Chroma Q and the discontinued Apollo Q series plus some others. The Camelonts were marketed through Rainbow and Strand. Both can be found as other brands.

[n1ist]

The DMX control part is not too tricky; almost any single-chip micro (AVR, PIC, MSP) can handle that. As mentioned, the trick will be indexing the media (gobo, gelstring) rather than dead-reconing. For a gobo rotator, if you have the gobo rigidly attatched to a geared disk, you can use a stepper and an optosensor to get an index pulse to find the start position. For a scroller, it is a bit trickier. I would use an optosensor to find the beginning of each color and another to do BOT/EOT. I would also either measure motor current or RPM to detect if the string is jammed or has pulled free.

[Arez]

Ah, but why even bother with an optical sensor, yes it would be nice but it's not needed, what you do is include an error margin on the gel to make up for tracking issues, you index the motor points and speeds and use math to calculate the location of the gel there by allowing you to choose colors at different levels.

[David Ashton]

Or you can buy some Chinese ones for $90, this gives you all the hardware for your project for less than you can make them.Now these usually work quite well anyway but you will be able to make it work much better, won't you?
Good luck.

[Arez]

Originally Posted by David Ashton

Or you can buy some Chinese ones for $90, this gives you all the hardware for your project for less than you can make them.Now these usually work quite well anyway but you will be able to make it work much better, won't you?
Good luck.

I'll bite, yes, I think I could turn a $90 scroller into a $250 scroller, depending on how its made and what construction materials it uses. Take it apart and use its shell as a rough template, see how well it fits in the instrument, and form a new template from it's concept which fits better and is more stable. Have multiple power supply options for daisy-chaining, same for control input, why make someone buy a new cable for each accessory, why not just have multiple inputs for ten extra dollars.

As far as a gobo-rotater, that can already be built for a very low price provided you have a grinder, dremel tool, drill press, tin snips, and some electrical tools, granted if you have a metal shop then you have better tools for the job. Conveniently, most shops have a majority of these tools or similar substitutions. So now all you need is a thinner sheet of the metal you would like, and then a thicker one, ball bearings,x amount of motors, heat shrink, connectors and a gobo. And you can build a small army of gobo-rotaters.

Which brings me to my last point, what is the correct spelling/terminology of "gobo-rotater?" because while I've heard the phrase used I have yet to see it spelled where spell check doesn't red-line it.

[lieperjp]

Originally Posted by Arez

Which brings me to my last point, what is the correct spelling/terminology of "gobo-rotater?" because while I've heard the phrase used I have yet to see it spelled where spell check doesn't red-line it.

The correct spelling is gobo rotator. It's jargon (language related to a specific and specialized job) so you won't find it in your spell checker. If the red line annoys you, right click on the line and select "Add to dictionary" and it won't be underlined anymore. It appears the hyphen is optional, but without is better.

[Les]

Rotator is the correct spelling (as opposed to rotater) however, you will still get the red line because apparently rotator is not a word (according to Firefox).

[TimMiller]

a simple rotator is easy to build, one that index's the gobo is more complex, but works nice for logos when you want them to rotate then stop with the logo being right side up. Does anyone actually make a indexing gobo rotator besides what is used in moving lights?