Half stepping driver?

Archiver

Hello all,
I realize most of the regulars here are familiar with using a
stamp and an L293D to drive small stepper motors. I'm wondering if it's
possible with this set up to half-step the motor? I've used commercial
microstepping drives for larger motors, but I'm looking for a solution that
will work with very small motors (and hopefully isn't too expensive). I
guess another idea would be small steppers with step counts higher than 200
- anyone know of any?

Thanks, Duncan

Archiver

At 12/28/2000 Thursday 10:57 PM -0500, orthner@s... wrote:

> Hello all,
> I realize most of the regulars here are familiar with using a
>stamp and an L293D to drive small stepper motors. I'm wondering if it's
>possible with this set up to half-step the motor? I've used commercial
>microstepping drives for larger motors, but I'm looking for a solution that
>will work with very small motors (and hopefully isn't too expensive). I
>guess another idea would be small steppers with step counts higher than 200
>- anyone know of any?
>
>Thanks, Duncan

Hi Duncan -

The E-Labs Stepper Motor drive chips [noparse][[/noparse]EDE-1200 and EDE-1204] will perform
almost any sort of stepping you might need with Uni-polar or Bi-polar steppers.
They offer a CDROM with their products and app notes are contained within. I
HIGHLY recommend this format, since in addition to all the data sheets for all
of their products, they package a small reference cards with the parameters
for all of their chips right on it ! You rarely need to reference the data
sheets !
The web site for E-Labs can be found here:

[noparse][[/noparse] http://www.elabinc.com/default.htm ]

and punch up the EDExx Family of ICs from the left hand menu. If you should
have any questions or need any design help using their chips, the folks at
E-Labs offer full support of their products, and would be happy to field any
input via E-mail.

In addition to the chips, a small module kit is also available for the
EDE-1200.
That kit can been viewed by punching up Modules on the same menu. The kit
contains both the EDE1200, and the ULN2003A power transistor driver array,
plus all the related components.

Hope that helps

Regards,

Bruce Bates

Archiver

Yes, the L293D will work great in full or half step mode. The only
difference is the step pattern. Following is a code snippet I was using with
a PIC14F84 and PICBasic Pro to drive a stepper with a L293D.

'******the following will drive a bipolar stepper through a L293D
'******Hookup info PIC L293D
' PORTA.0 DIRA2
' PORTA.1 DIRA1
' PORTA.2 DIRB1
' PORTA.3 DIRB2
DriveStepper:
For i = 3 TO 0 STEP -1 'Full Step
' For i = 7 TO 0 STEP -1 'Half Step
LookUp i,[noparse][[/noparse]%1010,%0110,%0101,%1001],mystep 'Full Step
' LookUp i,[noparse][[/noparse]%1010,%1000,%1001,%0001,%0101,%0100,%0110,%0010],mystep 'Half
Step
PORTA = mystep
Pause mySpeed
Next i
GOTO DriveStepper

Changing the variable mySpeed will change how fast the motors run. I found
that the fastest I could go with the motors and I was using and a 12 v power
supply was with mySpeed = 5 ms or so. Any faster and the motor would stall.
If you change the step value in the for loop to a positive 1 the motors will
go in the opposite direction.

Tim
[noparse][[/noparse]Denver, CO]

> Hello all,
> I realize most of the regulars here are familiar with using a
> stamp and an L293D to drive small stepper motors. I'm wondering if it's
> possible with this set up to half-step the motor? I've used commercial
> microstepping drives for larger motors, but I'm looking for a
> solution that
> will work with very small motors (and hopefully isn't too expensive). I
> guess another idea would be small steppers with step counts
> higher than 200
> - anyone know of any?
>
> Thanks, Duncan
>
>
>
>