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[DPRG] The quadrature blues

Subject: [DPRG] The quadrature blues
From: Kipton Moravec kip at kdream.com
Date: Wed Aug 29 09:25:15 CDT 2001

> I'm not sure I understand how reflective or transmissive should make a
> difference as to the number of divisions you can sense.
> On the other hand, I am humbled that it didn't occur to me to mount the
> sensors at an even 180 degree spacing and simply draw a wheel with an
> odd number of divisions instead of jumping through all these hoops to
> make an adjustable, and therefore unstable, sensor mounting.

You just have to have an odd number of holes for transmissive, or an odd
number of white for reflective.

If you do not, then at 180 degrees you will have the same signal on both

> In other news, I made a trip to Tanner's yesterday and purchased what
> may be the last two Pittman GM8712 motors they had. These are indeed
> wonderful little motors.
> They also had some other Pittman motors, without gearheads, that looked
> about the same size as the core of the GM8712. After I was already on
> the road again, it occurred to me that we might be able to swap out the
> armatures in the gearhead motors with the others to provide a longer
> motor shaft more suitable for mounting an optical encoder. Obviously,
> that involves pressing a pinion gear onto the new armature, but who
> knows, it might be worth it.

Great, now that I distroyed one trying to get the shaft tapped.  I only have
one. And they are out.
That is the way it goes.

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