Re: [CAD_CAM_EDM_DRO] rotary hand encoder wheels with detent

Hi Doug,

Yeah, I gotta agree, The stepper gives it a nice feel (but ya can't spin
it)! I must have been imagining (wishful thinking) that my encoder had
some feel.

Do I recall the last time we talked about using steppers for encoders,
that there was a circuit for a "pulse generator" or "quadrature
generator" for a stepper? I haven't sat down to see if I can figure one
out, but it seems that a few opamp comp's, and perhaps a few F/F's
should be able to generate quadrature signals. Anybody wanna give it a
try?

I'm USING my brand new dual shaft steppers!

Alan KM6VV


Doug Fortune wrote:

>
> Alan Marconett KM6VV wrote:
>
> > Are you saying that the pulse generating hand wheels
> > actually have some force feedback, or that you can
> > feel the steps (detents?) of the encoder? So once
> > zeroed, their scales remain accurate to position,
> > just like a manual mill?
>
> How about just using a big knob connected to a small
> dual shaft NEMA 17 or NEMA 23 stepper motor (to give
> the quality 'feel' of detents), and add an encoder to
> the back of the stepper for feedback to the computer.
>
> The stepper motor is not connected up, its just there
> to add the 'feel'.....
>
> If the encoder has the same resolution as the steps
> of the motor, so much the better.
>
> Here is an improvement: I just grabbed a slo-syn NEMA23
> 200 step stepper off the the shelf (this one is dual stack)
> to 'feel' it, and it does feel nice.. those little
> detents just whip off...
>
> However, shorting some of the leads causes the motor to
> be difficult to turn (this is no surprise), so much so
> that individual steps can be felt and almost counted! ..
> it is hard to turn it more than 10 or 15 steps/second....
> so that it would be easy to rotate into a given particular
> spot without overshooting it. Thus maybe a pushbutton
> should be placed on the panel somewhere to put the
> 'encoder wheel' into this mode for
> 'sneaking up' to a precise position.
>
> Everybody try this at home with your spare steppers!
>
> Also note that the real cheap 7.5 degree or 15 degree
> steppers could also be used, if you wanted 'big hops'
> between steps, instead of little mini ones.
>
> Doug Fortune
> http://www.cncKITS.com