Design Issues and Solutions -

[Boberto333]

I'm planning to create my very won CYM Color mixer. Right now the plan is to use a Northlight 8 Channel DMX Servo Controller (available here: DMX512 to RC servo controller.) to control two servers hooked up to gearboxes, which are in turn attached to rotating drums which will hold the gel strings. The level of the dimmer that the Northlight chip is adressed to controls where the servo is positioned, two dimmer levels will control the position of both gel strings. So the idea is that for each 90 or 180 degree turn of the servo, the gearboxes will rotate the drums around 25 times, scrolling through each entire gel string, all based on the level of the dimmer.

This is my summer project and I hope to get started on it early May. I might order the Northlight chip now.

Ideas, tips, suggestions?

[MNicolai]

It's a nice idea, and there are other threads that go into pretty good detail already if you run a search, but you'll find the common theme is that it's more trouble than it's worth.

You may find that you can create one that works alright, but then you want two. Then you have two and want four. So you've now made four, seemingly identical, units, but typically DIY's result in a quality control inconsistency from unit to unit. That said, you could make four perfect gel scrollers for the price of one via retail, but you shouldn't expect that they'll be and act as identical units, arriving at the same position of a string at the same time.

Another issue you may face is the technology within gel scrollers that you don't see. For example, the magnetic strips on the strings that tell the device that it's reached the end of the string and needs to stop scrolling or the string will be ripped off of the unit. There's also a lot of R&D that goes into keeping scrollers quiet and accurate. Just as movers find the home positions of their motors, scrollers when turned on will run to both ends of the gel string to find their home.

All said and done, you'll have yourself a cheap DIY solution that will get the job done in a bind, but I'd be very hesitant about running 20 of those DIY units all at once.

That said, if you do build your own scrollers, please do take photos, post your assembly steps, and tell us how well it works.


EDIT:
Also, please be careful about your wording. If you're planning on adjusting your DMX values being sent to the scrollers by tieing into your dimming racks, then you may need to study up on DMX a little more before carrying out your project.

[Boberto333]

That's a good point about inconsistency among each one. I'll just have to plan on manually adjusting each. I would certainly spring for retail if only our department budget allowed it, but we are a public high school, so I'm afraid that's out the window.
At the very least it will be a fun project, I suppose, even if it doesn't quite work out.

Oh and I'm just planning on tying into the DMX network, not the dimmer rack. The Northlight should make that part easy.

[MNicolai]

Are you a high school student, or a staff member?

An option you would have if you got one working, is then also the ability to show people how powerful gel scrollers are, and then having something to lobby the higher powers with to try and allocate funds to purchase proper devices.

Consider when roadhouses are packed with conventionals, and them some touring group brings in their rig of movers, which will usually then be followed by a couple weeks of subtle comments from staff members and patrons, "We should consider getting some of those."

[Boberto333]

I'm a student, in my junior year at George Washington High School in Denver, Co.

That's not a bad idea! Our theatre program is also sort of "on the rise," because of some recent successes and a number of very generous parents. A complete renovation of the acoustics is next on the checklist but there might be some room in the budget for new lighting fixtures and accessories.

[MNicolai]

If you make a scroller that turns out to work pretty well, make sure you hold on to it and photos and details of how you made it. That's a great thing to throw in portfolios when you're interviewing at colleges or for jobs. It shows initiative in engineering design while also shedding light on your hands-on skills that would be useful for service or install technicians. Even if you're going into something completely unrelated, it's telling example of your character.

That said, I give you major points if you built a DIY scroller working.