Planar Motion Mechanism at DVinfo.net

John Jay · July 21st, 2004, 01:33 PM

Been looking for a cheap, easy to build with readily available parts and no specialist tools system for you know what

Motors, pulleys, rods etc obtained here >

http://www.mfacomodrills.com/pdfs/gbxbrch1.pdf

springs from here >

http://www.ondrives.com/products.asp?recnumber=313

last but not least is an mpeg1 movie showing the logical operation

please right click below for download - 30 meg per day limit!!

http://home.ripway.com/2004-7/146010/pmm/PMM.mpg

if anyone can host the mpeg - please do!

Brett Erskine · July 22nd, 2004, 02:02 AM

Thanks for the link. I noticed alot of useful parts like antiviberation mounts, mounted bearings and pulleys. Good find!

John Jay · July 22nd, 2004, 02:14 PM

the key to success is not so much in the method of producing the 'deliberate motion' but rather achieving an acceptable level of vibration.

remember a 1 pixel vibration (=36/720 = 0.05mm) is like turning the custom sharpness down to the minimum on most cameras

a good test with any design would be to shoot a 1956 chart with the rig spinning to guage how much loss of resolution is present due to vibration - you can easily spend $100-300 on quality anti-vibration mounts

also my tests show that the amplitude of 'deliberate motion' should be at least 2mm (on a Nikon F3D GG) without seeing any grain up to F8.0 - even then the GG is smoothly grey and acts like a Neutral Density filter

Dan Diaconu · January 10th, 2005, 12:18 PM

John,
In my experience, I saw no need to create a motion bigger than 0.2 mm (the whole GG roating)
It seems to be enough to mix&blend all grain whithin itself.
I can not "see" it (providing there is enough light) stopping down to 16 on the SLR lens.
Speed should only follow this simple logic:
If one shoots 1/60, than all you need for every frame is one (or LESS!!!!) complete circle for every grain of the GG.
Tests got me to this result (not theory)
At this level of motion (and speed) all it takes is a very precise, eficient and small motion generator (which I have made)
The NOISE and VIBRATION LEVEL are to a MINIMUM due to small mass moving. Hence the low power needed to get it all in motion.
Are you still following this path ? (gg oscilating)

Kyle Edwards · January 10th, 2005, 02:58 PM

You can host the MPG at www.yousendit.com.

July 21st, 2004, 01:33 PM	#1
John Jay Major Player Join Date: Sep 2002 Location: US & THEM Posts: 827	Planar Motion Mechanism Been looking for a cheap, easy to build with readily available parts and no specialist tools system for you know what Motors, pulleys, rods etc obtained here > http://www.mfacomodrills.com/pdfs/gbxbrch1.pdf springs from here > http://www.ondrives.com/products.asp?recnumber=313 last but not least is an mpeg1 movie showing the logical operation please right click below for download - 30 meg per day limit!! http://home.ripway.com/2004-7/146010/pmm/PMM.mpg if anyone can host the mpeg - please do! __________________ John Jay Beware *PLUGGER-BYTES*

July 22nd, 2004, 02:14 PM	#3
John Jay Major Player Join Date: Sep 2002 Location: US & THEM Posts: 827	the key to success is not so much in the method of producing the 'deliberate motion' but rather achieving an acceptable level of vibration. remember a 1 pixel vibration (=36/720 = 0.05mm) is like turning the custom sharpness down to the minimum on most cameras a good test with any design would be to shoot a 1956 chart with the rig spinning to guage how much loss of resolution is present due to vibration - you can easily spend $100-300 on quality anti-vibration mounts also my tests show that the amplitude of 'deliberate motion' should be at least 2mm (on a Nikon F3D GG) without seeing any grain up to F8.0 - even then the GG is smoothly grey and acts like a Neutral Density filter __________________ John Jay Beware *PLUGGER-BYTES*

July 22nd, 2004, 02:02 AM	#2
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Thanks for the link. I noticed alot of useful parts like antiviberation mounts, mounted bearings and pulleys. Good find!

January 10th, 2005, 12:18 PM	#4
Dan Diaconu Major Player Join Date: Dec 2004 Location: Vancouver, Canada Posts: 804	John, In my experience, I saw no need to create a motion bigger than 0.2 mm (the whole GG roating) It seems to be enough to mix&blend all grain whithin itself. I can not "see" it (providing there is enough light) stopping down to 16 on the SLR lens. Speed should only follow this simple logic: If one shoots 1/60, than all you need for every frame is one (or LESS!!!!) complete circle for every grain of the GG. Tests got me to this result (not theory) At this level of motion (and speed) all it takes is a very precise, eficient and small motion generator (which I have made) The NOISE and VIBRATION LEVEL are to a MINIMUM due to small mass moving. Hence the low power needed to get it all in motion. Are you still following this path ? (gg oscilating)

January 10th, 2005, 02:58 PM	#5
Kyle Edwards Major Player Join Date: Nov 2004 Location: LI, NY Posts: 274	You can host the MPG at www.yousendit.com.