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PWM command - is it the right way to control small DC motor? — Parallax Forums

PWM command - is it the right way to control small DC motor?

ArchiverArchiver Posts: 46,084
edited 2003-02-16 04:01 in General Discussion
Greetings -

I'm kinda new to working with Basic Stamps - been playing around with
hacked servos for locomotion, and want to start using DC motors. I've
been messing around a bit with L298 and TI 754410 h-bridge drivers for
speed/direction control (mainly 754410 because it does not require
additional diodes...). I'd also like to start working with PWM for
motor control, and from what I've read so far, the PWM command for the
stamp leaves a bit to be desired. Yes/No? It seems that most people
use an additional chip (PAK V/VIII) to generate PWM signals for a
driver chip or use a self-contained external circuit (Motor Mind or
equivalent).

What's the best approach for motor control?
What are the pros and cons of using the stamp PWM command?
What are other people doing for motor control?

Sorry for the barrage of questions.

Thanks in advance for any help/advice.

Regards,
Jeff

PS - great forum here!

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-02-16 03:46
    The PWM command is not intended for motor control; its purpose is for
    digital-to-analog output (using a buffered RC network).

    For the best results, you'll need to use a motor controller. There are many
    available, from us and from other vendors.

    -- Jon Williams
    -- Parallax

    In a message dated 2/15/2003 6:46:52 PM Central Standard Time,
    jlsabala@y... writes:

    > Greetings -
    >
    > I'm kinda new to working with Basic Stamps - been playing around with
    > hacked servos for locomotion, and want to start using DC motors. I've
    > been messing around a bit with L298 and TI 754410 h-bridge drivers for
    > speed/direction control (mainly 754410 because it does not require
    > additional diodes...). I'd also like to start working with PWM for
    > motor control, and from what I've read so far, the PWM command for the
    > stamp leaves a bit to be desired. Yes/No? It seems that most people
    > use an additional chip (PAK V/VIII) to generate PWM signals for a
    > driver chip or use a self-contained external circuit (Motor Mind or
    > equivalent).
    >
    > What's the best approach for motor control?
    > What are the pros and cons of using the stamp PWM command?
    > What are other people doing for motor control?
    >
    > Sorry for the barrage of questions.
    >
    > Thanks in advance for any help/advice.
    >
    > Regards,
    > Jeff
    >
    > PS - great forum here!



    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-02-16 04:01
    The lazy-man's method for doing motor speed control with a Stamp is PULSOUT.
    Its rather limited and the Stamp can't do much else while you are sending
    pulses to the motor, but it does work. You essentially have a tight program
    loop with a PULSOUT statement in it. You vary the width of the pulse to
    control the motor speed.

    Original Message

    > The PWM command is not intended for motor control; its purpose is for
    > digital-to-analog output (using a buffered RC network).
    >
    > For the best results, you'll need to use a motor controller. There are
    many
    > available, from us and from other vendors.

    > > I'm kinda new to working with Basic Stamps - been playing around with
    > > hacked servos for locomotion, and want to start using DC motors. I've
    > > been messing around a bit with L298 and TI 754410 h-bridge drivers for
    > > speed/direction control (mainly 754410 because it does not require
    > > additional diodes...). I'd also like to start working with PWM for
    > > motor control, and from what I've read so far, the PWM command for the
    > > stamp leaves a bit to be desired. Yes/No? It seems that most people
    > > use an additional chip (PAK V/VIII) to generate PWM signals for a
    > > driver chip or use a self-contained external circuit (Motor Mind or
    > > equivalent).
    > >
    > > What's the best approach for motor control?
    > > What are the pros and cons of using the stamp PWM command?
    > > What are other people doing for motor control?
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