Merry Christmas everyone...
Originally Posted by danwee
Read it once more and got 90% of what you said. Some questions.
1.When you order roller tubes you have to get them from somfy or can you use something cheap from the local hardware store?
2. What do you think using a stepping motor instead of expensive somfy motor.
3.Instead of crossing the bungys at midway channel, why didn't you just swap the channels on the opposite end?
Danwee, there is lots of information (and debate) about the differences between zooming and using and anamorphic lens elsewhere on the forum. With the advent of 4K and bright, high contrast projectors the advantages of going Anamorphic are dwindling but essentially it allows for maximum projector resolution and squeezes some extra brightness out of a projector.
As for your questions:
1. I obtained the rollers from (random) blind dealer on the web. I can't remember the name off the top of my head. All you need is the right size of Aluminium tubing and some strong double sided sticky tape to attach the end of fabric. Make sure you retain at least one wrap minimum to prevent the fabric from pulling off.
2. I was originally going to use a stepper motor and build a control circuit. The decision is one of effort vs reward... the Somfy motors can remember 5 different stops and are simple to automate. The equivalent stepper motor control circuitry/software would be quite complex and probably just as expensive, if not more so. If you want just two positions/aspect ratios (open and closed) then an external sensor to detect the stop position would simplify things. The beauty of the Somfy system is multiple stops/aspect ratios, quick setup and easy programming/control.
3. If I understand what you are saying correctly then this might work so long as you get enough stretch (and recall "pull") out of the short bungy cord. My design was to create a constant pull over the entire range of movement. If the bungy is too short, it wont pull strong enough at the minimum aspect ratio... the longer the bungy the more constant the recall force.
Hope this helps...