I need to rotate a piece of optics that is about one inch diameter by
one inch long over a 90 degree range. Either continuous controllable
angle or just 0 and 90 degree positions. Looking for ideas for either
method. Is there a ready to go gear arrangement or servo that can
accomodate this ? A servo could be linked (by gear, pulley, foam
wheel, etc ) to a ring gear bearing holding the object, but I'm trying
to come as close as possible to a ready to go solution.
You might look into the mechanisms used to rotate the antenna in a
satellite dish low noise amplifier/block converter. They use a servo
connected to a mechaism that rotates the receiving element 90 degrees
back and forth.
It all depends on the size of the optics, which you didn't mention in
If you're at all handy with tools you could build something. Use a
largish gear and mount the optics inside it (drilling out the center as
needed). Get three smaller gears and mount them at 12, 3, and 6 o'clock.
Accuracy will be critical here. Mount a final last gear, connected to a
servo, at 9 o'clock. This one rotates the center gear; the other three
gears merely serve as pinions. You can get mating gears of different
diameters from Servocity.com. They sell some that are made to attach
directly to servos.
Finally check out Kelvin.com and look at their gear sets. They sell one
or two that come with brackets for making various types of gear systems.
They're pretty cheap...under $10 or so.
Author: Constructing Robot Bases,
Robot Builder's Sourcebook, Robot Builder's Bonanza
Steve Parus wrote:
As others have suggested, you haven't provided enough information.
If all you need is rotation between 0 and 90, you could make two stops
accurately and use a clutch type arrangement (e.g., motor driving a pulley
via a loose belt). You could use magnets to insure good contact with the
stops after the motor turns off. Maybe this isn't any more off-the-shelf
than what you are already considering though.
there might be a "geneva mechanism" that you can purchase to fit your needs.
Do a websearch and see. Constant or on/off motor input provides incremental
rotary output, typically in 90 degree increments.
(Gawd, can you tell how old I am from that statement?)
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