Subject:
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Re: stepper motors
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 25 Jun 1998 17:09:08 GMT
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Original-From:
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Peter Harrison <peter.harrison@cannock.ac.uk*NoSpam*>
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Viewed:
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1198 times
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brian-c@technologist.com wrote:
>
> A while back a few people pointed me to an text about using stepper
> motors with the handy board.
> http://www.cctc.demon.co.uk/stepper.htm
>
> To the people who have told me about this, or have used this method to
> control steppers: please tell me how well you have gotten your motors
> working. I have tried the sample code and my motors are a little
> sketchy. When they first power up, they jerk left or right a little,
> causing my robot to align incorrectly. Also on the turns they
> sometimes jerk a little causing my turns to be thrown off.
>
> ...all stepper people *HELP ME* !
Its my code and you are quite right - it is not the best in the world.
It was only intended to illustrate a point and I have done no more work
on it since then - sorry.
When first powered up the steppers will align themselves according to
the pattern sent to them so there will almost certainly be a little
shuffling around as they take up their detent positions. Half stepping
the motors will probably reduce the effect. If initial alignment is a
particular problem for you - as it might be in a competition say - then
you might like to power up the motors, position the robot then power
them down.
As for turns, I don't really know the answer. Bear in mind though that
the timing of motor pulses is important for reliable operation of the
steppers, especially at high speeds. If you want to drive the steppers
faster you will probably need to hook into the system interrupt (I don't
know how) and ensure that the motor signals are sent at well defined
intervals. I would expect system interrupts to interfere with the timing
in the sample code.
Pete
--
=====================================================
peter.harrison@cannock.ac.uk
Cannock Chase Technical College
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Message is in Reply To:
 | | stepper motors
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| A while back a few people pointed me to an text about using stepper motors with the handy board. (URL) To the people who have told me about this, or have used this method to control steppers: please tell me how well you have gotten your motors (...) (26 years ago, 25-Jun-98, to lugnet.robotics.handyboard)
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