I'm looking for a servo motor with a hollow center section of at least
0.5 inches diameter. I want to place an optical polarizer there through which light will pass and be able to rotate the polarizer about its center axis. Alternativley, a servo mechanically coupled to such a hollow holder. A servo because it is easy to define and control the optical angle.
You could use a setup with bearings on the outside with a hole in the center, and have the servo rotate the center race which has the filter attached. Could be as simple as a ball bearing with a
1" center hole, or a plastic lazy susan from Walmart (bearing tolerances a little lose on this!).Newport sells one for USD$7500.00
look for "360 degree rotation stages"
Opto sigma has a non-motorized one for USD$500
Most autofocus cameras have an aperture / ring servo type of arrangement in the case (if it`s a compact), but also actually in the Lens (if it`s an SLR). It might be worth dismantling one of these if you can get hold of one really cheap.
----------------------------------------------------------------------- Ashley Clarke
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You can buy such things from the usual optical supply houses, Oriel or Meilles Griot. They both sell precision optical positioning servo systems. Expensive, but precise.
John Nagle
Si Ballenger wrote:
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