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stepper motor control with uln2803 — Parallax Forums

stepper motor control with uln2803

Vertex78Vertex78 Posts: 51
edited 2006-04-01 00:49 in BASIC Stamp
I purchased the stepper motor from parallax, it is 7.5 degree/step 12v 100ohm

using the instructions on this link
http://www.parallax.com/dl/docs/prod/motors/Stepper_Motor_27964.pdf

I have tried the full step(high torque) way and the high precision way of driving the motor. But both ways it barely takes any effort at all to stop the motor from spinning with my hand. What can I do to increase the torque even more?

I am driving the chip and motor with 12v and·5 volts for the logic, just like in the diagram in the pdf link above.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-03-31 20:18
    Hello,

    ·· The Stepper Motor we carry isn't very high-torque and is intended for learning.· If you need more torque you should purchase one with the specifications you require at the voltage you're using.· It also helps to make sure your power supply can provide enough current.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • dandreaedandreae Posts: 1,375
    edited 2006-04-01 00:15
    You can also use gearing to increase the torque.·

    Dave

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    Dave Andreae

    Tech Support
    dandreae@parallax.com
    Http://www.parallax.com

    ·
  • Vertex78Vertex78 Posts: 51
    edited 2006-04-01 00:44
    Well, i salvaged a bipolar stepper motor out of a printer and hooked it up to a l298 chip. I managed to get the motor turning but it gets really hot after about 30 seconds, almost to hot to touch. The only thing I know about the motor is that on the label it says 4ohm



    Here is the basic stamp code i made to run it, it's nothing special, just threw it together to see if i could get the motor to turn

    ' {$STAMP BS2}
    ' {$PBASIC 2.5}

    'P0 is enable a

    'p1 is enable b

    'p2 and p3 is coil 1

    'p4 and p5 is coil 2

    enableA CON 0
    enableB CON 1

    high enableA
    high enableB

    x VAR Word
    DO

    FOR x = 0 TO 10
    · GOSUB revs
    NEXT

    FOR x = 0 TO 10
    · GOSUB foward
    NEXT

    LOOP

    foward:
    'step1:
    · HIGH 2
    · LOW 3
    · LOW 4
    · HIGH 5

    · PAUSE 20

    'step2:
    · HIGH 2
    · LOW 3
    · HIGH 4
    · LOW 5

    · PAUSE 20

    'step3:
    · LOW 2
    · HIGH 3
    · HIGH 4
    · LOW 5

    · PAUSE 20

    'step4:
    · LOW 2
    · HIGH 3
    · LOW 4
    · HIGH 5

    · PAUSE 20

    RETURN

    revs:
    'step4:
    · LOW 2
    · HIGH 3
    · LOW 4
    · HIGH 5

    · PAUSE 20

    'step3:
    · LOW 2
    · HIGH 3
    · HIGH 4
    · LOW 5

    · PAUSE 20

    'step2:
    · HIGH 2
    · LOW 3
    · HIGH 4
    · LOW 5

    · PAUSE 20

    'step1:
    · HIGH 2
    · LOW 3
    · LOW 4
    · HIGH 5

    · PAUSE 20

    RETURN




    Post Edited (Vertex78) : 4/1/2006 3:27:37 AM GMT
  • dandreaedandreae Posts: 1,375
    edited 2006-04-01 00:49
    Stepper motors do run hot, that is normal regarding stepper motors.· Make sure that you verify the stepper motor ·specifications with your power supply.

    Dave

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Dave Andreae

    Tech Support
    dandreae@parallax.com
    Http://www.parallax.com

    ·
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