BASIC stamps and stepper motors
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Posts: 46,084
I have a BS2 that I am trying to interface with a unipolar stepper
motor. Does anyone have any suggestions as to what the best way to
do this might be. I would really appreciate any input.
motor. Does anyone have any suggestions as to what the best way to
do this might be. I would really appreciate any input.
Comments
Look up experiment #26 in the Stampworks. It shows how to use a unipolar
stepper with a Stamp and a ULN2003. Bipolars are a little harder but can be
used as well. What kind of stepper do you want to use?
Jonathan
www.madlabs.info
Original Message
From: <jtalaman@i...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, June 09, 2004 10:43 AM
Subject: [noparse][[/noparse]basicstamps] BASIC stamps and stepper motors
> I have a BS2 that I am trying to interface with a unipolar stepper
> motor. Does anyone have any suggestions as to what the best way to
> do this might be. I would really appreciate any input.
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http://www.parallax.com/dl/docs/prod/motors/27964.pdf
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: jtalaman@i... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=CRzaKO6LyATY7CuY45OgsWK-uwQ2IY8Jps30q29DwLriAurX-XADAwzKiwL1zEf26uK1EE9Bklw]jtalaman@i...[/url
Sent: Wednesday, June 09, 2004 12:44 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] BASIC stamps and stepper motors
I have a BS2 that I am trying to interface with a unipolar stepper
motor. Does anyone have any suggestions as to what the best way to
do this might be. I would really appreciate any input.
> I have a BS2 that I am trying to interface with a unipolar stepper
> motor. Does anyone have any suggestions as to what the best way to
> do this might be. I would really appreciate any input.
There are a few schools of thought, but to help in termonology.
The 'contoller' is the logic device, the PC or the Stamp, but it is
the intelegence that wants to do something.
the "driver" is the device that receives signals from the controller
and then sends out power to the motor. These two terms sometimes get
lost or swapped, and there is nothing more frustrating that using one
set of terms for hobby stuff, then trying to talk to professionals
who use them in a different way.
The Stamp is the CONTROLLER, the darlington or H-Bridge is the DRIVER.
there are very complicated controllers and very complicated drivers
so getting the termonology correct up-front should help.
#1) motor stepping speed. how fast do you need to go ?
When you just need to move some few hundred khz, you have lots of
options. getting into the thousands of khz, considder a pre-packaged
device. Getting into hundreds of thousands of khz, requires
extensive knoledge so that is not often considders a hobby area.
A low speed stepper will run fine with something like a ULN2803 or
individual darlingtons. Once you start getting into high speeds, you
have a back EMF that can be a benifit or a disaster. It can be used
to add power back into your circuit to boost it, or it can zap your
chips. Typically, the easiest is to use a diode and protect the
chips.
As you need higher speeds look into stepper driver chips of different
types. there are quite a few.
need more than 10,000khz? considder a pre-packaged circuit, ditto
for anything over about 1.5 amps, and only considder an actual
stepper driver board for machine control. These get pretty intensive
when you need machine tool torque.
#2) power. and this goes with torque. A stepper motor has an ohms
law base to allow you to design things. This is the 'nameplate' text
of the on the motor. This is NOT the limit, but the starting place
for driver design. Current is the current is the current. If it is
rated for 1 amp, don't expect to ever put more thru it. If you want
a hobby driver, then you are limited to using the nameplate voltage.
But chopper drivers are available for getting much higher performance
from a stepper, and using much higher voltages.
If you design a chopper driver, you not only can, but should put 20x
the rated voltage thru the thing.
For hobby stuff, we design with a dead short current on the motors so
you are limited to nameplate voltage and current. Chopper drivers
can handle the difference.
Anyway, since you said UNI-polar, I assume you mean hobby and there
are a bunch of simple circuits to control them.
I think some others posted some links to notes from Parallax so start
there.
Dave