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Old June 28th, 2004, 08:59 AM   #31
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They don't seem to have a fluid optical filter covered. (Some text here was deleted by myself until some tech patent details are checked.)
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Old July 1st, 2004, 07:57 PM   #32
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Just wondering why you guys aren't figuring out exactly how P+S Technik moves their ground glass...The design plans have already been posted you know. No tape, no glue, no wood and they dont even use bubble gum to put their together. There is a difference between cheap and inexpensive.
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Old July 1st, 2004, 08:20 PM   #33
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Answer: why using office supplies to make things

There is a post on how p+S puts it together.
The reason most people are not going that route is that they don't have the machine tools to do so.
I do.
This weekend, I will be assembling something to wiggle a small substrate myself. It will use 9 ball bearings in it's construction, and be made of AL.
I may make a kit of this available to others to experiment with.
-Les




<<<-- Originally posted by Brett Erskine : Just wondering why you guys aren't figuring out exactly how P+S Technik moves their ground glass...The design plans have already been posted you know. No tape, no glue, no wood and they dont even use bubble gum to put their together. There is a difference between cheap and inexpensive. -->>>
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Old July 2nd, 2004, 01:10 AM   #34
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Les, you know how the original adapter work. I also know it. We build those one, and some different models. One is more quietly than the original, but with the same optical features, and we have the better GG. Also, i found ways to go around the patent and will have own patents. I think we should talk together, and maybe... we can work together? Letīs email
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Old July 2nd, 2004, 10:21 AM   #35
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Hey guys I am working on an idea as well but all this patent stuff is freaking me out. I would like to build a rig that I could sell but I would also like the idea to be free to everyone. I have a way to work around the PS patent as well but I am not sure Rai and I have the same thought. Either way if my idea is different I would like a way to make sure it never gets patented and anyone can use it if they want. I am also a little wary about just announcing it for fear some one else tries to patent it. Does anyone no how these patent laws work, is there a way to give an original idea free license?
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Old July 3rd, 2004, 03:08 PM   #36
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How to make a quiet, smooth oscillating mechanism

Make sure your movement is extrememly small to avoid excessive vibration of the camera itself. You only want to make the GG move. Anything more and your might have vibrations show up in your footage because you camera itself is shaking. This will also help in reducing sound problems.

Here are some other things that will help produce a oscillating mechanism thats not only quiet but only vibrates the GG and not the camera.

1)Make whatever is oscillating (the GG and mechanism) balanced as perfectly as possible and as LIGHT WEIGHT as possible.

2)To make it alot quieter use large rubber O-rings instead of gears to move your mechanism.

3)Mount anything that moves or makes noise on rubber mounts to contain not only sound but vibration

4)Use a housing that is completely enclosed and perhaps even insulated.

5)Always use tiny bearings on moving parts v.s. bushings

6)Find a small electric motor thats runs quiet and smoothly at a speed thats works for the gg, noise, and vibration problems.

Good luck guys.
-Brett Erskine
www.CinematographerReels.com
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Old July 3rd, 2004, 03:19 PM   #37
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One possible source for small bearings, motors, etc, would be a hobby store (r/c car parts)
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Old July 6th, 2004, 03:33 AM   #38
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update

I worked on the prototype of my 'mini-shaker' and it is about 80% complete. It moves a substrate in about a 1 mm radius. The alignment of the bearings is pretty critical, and I will have to remake one of the parts to get it moving a bit smoother. It's constructed mostly of Aluminum,stainless steel, Nylon , Lexan and 9 micro ball bearings. No office or kitchen supplies used ;)
I'll post pics of the core tomorrow.
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Old July 6th, 2004, 04:38 AM   #39
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Les.

Are you rotating a hollow eccentric around a fixed center carrying the GG? This is the most compact way to go but would need to have more than five mini-ballbearings, more like about fifty. Method for this would be two snug fitting races the outer eccentric ring driven by a belt, the inner ring + gg retained from spinning by another fixed belt = less noisy and wear-prone than a linkrod or sliding keyway and pin. The broader crescent portion of the eccentric ring might have to be drilled to bring the balance back to the mass of the GG and its own ring, or maybe some lead mass added into drillholes if you use hard aluminium alloy.

To centre the loading on a single row bearing there would have to be two drive belts, one each side of the bearing row and the third fixed belt might have to be doubled for loading balance too. Skewing the two fixed belts equally would assist to stabilise the gg assembly.

It would be simpler to home-build on a hobby lathe and superior to P+S Teckniks' published mechanism but more prone to wear and contamination from belt particles which is probably why they didn't go there.

Roller wheel drives are fine but are a mongrel to keep correctly set up and compensate for wear without introducing too much friction unless you use a third relay roller like an older style turntable which regulates its own pressure with a spring arm.
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Old July 6th, 2004, 05:18 PM   #40
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I did the three offset shaft type. I don't think the belt will shed too much, I am looking for a nice silicon belt, they last a long time and are sticky as well.
-Les
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Old July 6th, 2004, 09:16 PM   #41
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Les-
Looks like we are both working in the exact same direction. I'm going with a belt and off set shaft system as well. I found a single pulley wheel that houses everything for one shaft. Im using two micro bearings (each just a few mm in size) and a wheel that has pre drilled holes for the two bearings to drop into. The wheel also has a notch along the outer edge for a pulley to set into. I was looking for something ready made because at such a small scale all of the parts that are duplicates have to be EXACTLY the same. If you drill or make your own ...they better be carbon copies otherwise your going to have a loud or rough running mechanism. For thoughs interested I found the micro sized bearings and the pulley wheel at a hobby store. Sounds like you are using a shaft instead that is off set and then you've attached bearings to it. That should work well. In fact your design opens yourself up to having a tighter oscillation radius. Mine is a bit larger - about the sized of a dime. Where did you find thoughs shafts?

-Brett Erskine
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Old July 6th, 2004, 10:24 PM   #42
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Brett,
I made the eccentric shafts on my lathe. I'm guessing on the radius, I think the diameter of the motion is about 3mm now that I look at it in motion. I'm still only turning it by hand, I'm wondering if I will have to do any special vibration isolation. I made the part that moves from lexan to keep it light.
You are right about the precision needed to make this work, I did the drilling of both support plates at the same time to keep good alignment. I'm going to work on it a bit more tonight, to tune it up a bit. I'll try it with my HDV camera in a few days.
-Les
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Old July 8th, 2004, 03:00 AM   #43
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Les and Brett,
tighter oszillation produce also small (outside) vibration. A good GG need only small oszillation. It looks you working in the same direction like P+S (The original is also not 100% loudless. If you hold it in your hands, without lenses, you feel the vibration. It need the mass of lenses+camera to reduce the vibration!).

We had also tray this way. Here our details (itīs 99,5% like the original).

http://de.geocities.com/raiorz/vibro_old/vibro1.jpg

Next days you will found more details and also a different and more simply way...
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Old July 8th, 2004, 03:38 AM   #44
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to Rai

rai, exellent drawings. this is something i missed when i recently looked at p+s shematics. now i understand how it works.

exellent job.

can you just explain me how the platform with GG is mounted not to move in anoter directions (closer/further) but just to turn in excentric circles.

thank you

filip
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Old July 8th, 2004, 05:20 AM   #45
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Filip,
our ball bearings are all firmly pressed in (But also you can hold it with springs, clasp or simply bonded), so the GG platform can not move clother or further. The only play is in the bearings. It is far under 1/100mm. But (if you want, and we found there is no need) you can place little magnets on the still platform and on the GG platform, so the magnetic power pulls the platform always to itself.
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