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Speed and position control using a data bus — Parallax Forums

Speed and position control using a data bus

ArchiverArchiver Posts: 46,084
edited 2003-07-24 14:34 in General Discussion
Hello.

I was wondering if someone could help. I need to control a lot of
motors with the least possible number of Stamps. I am using the
BS2p40 and have come up with a circuit schematic that I think may
just work.

As my electronics knowledge is a bit poor, I was wondering if someone
could have a quick look at the file that I have uploaded to the files
section called:

Motor_Control_Schematic.pdf

My main question is will it in theory work or am I using a
sledgehammer to crack the nut?

I was trying to be able to address the item needed and then ping the
enable line so that the circuit collects the data on the bus. The
speed side of the circuit would create a PWM signal whos size depends
on the data on the bus. The position side of the circuit would
produce an analog voltage for the comparator to work with. The PWM
signal would control how fast the comparator can power the motor to
get to the desired position...

Am I on the wrong track completely or might it just work???

If you can help I would be very very greatfull.

/A

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-07-23 18:09
    At 03:24 PM 7/23/03 +0000, thor69uk wrote:
    >Hello.
    >
    >I was wondering if someone could help. I need to control a lot of
    >motors with the least possible number of Stamps. I am using the
    >BS2p40 and have come up with a circuit schematic that I think may
    >just work.

    It's hard to tell what kind of motors you have based on the schematic. It
    would help if we knew what kind of motors these were. There may be easier
    or less complicated methods depending on the type of motors. What is the
    total number
    of motors you were hoping to control ?

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-24 10:18
    Bruce,

    Thanks for getting back to me.

    There will be 14 motors in all and all of them will be 8.4V and 1 amp
    running current.

    Can you suggest any other ways or do you need more info...

    Thanks again,

    Andy.


    --- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...> wrote:
    > At 03:24 PM 7/23/03 +0000, thor69uk wrote:
    > >Hello.
    > >
    > >I was wondering if someone could help. I need to control a lot of
    > >motors with the least possible number of Stamps. I am using the
    > >BS2p40 and have come up with a circuit schematic that I think may
    > >just work.
    >
    > It's hard to tell what kind of motors you have based on the
    schematic. It
    > would help if we knew what kind of motors these were. There may be
    easier
    > or less complicated methods depending on the type of motors. What
    is the
    > total number
    > of motors you were hoping to control ?
    >
    > Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-24 10:31
    At 09:18 AM 7/24/03 +0000, thor69uk wrote:
    >Bruce,
    >
    >Thanks for getting back to me.
    >
    >There will be 14 motors in all and all of them will be 8.4V and 1 amp
    >running current.
    >
    >Can you suggest any other ways or do you need more info...
    >
    >Thanks again,
    >
    >Andy.
    Hi Andy -

    Are these AC powered or DC powered motors ? Are they servo motors, stepper
    motors, or some other type ? Are they in close proximity to one another, or
    are there great distances between the motors and/or the controller you
    propose ?
    Are you replacing an existing system, and if so, what type ?

    That should be a start towards an appropriate answer to your needs.

    Regards,

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-24 12:09
    Bruce,

    The motors are normal hobby DC motors. They will be quite severly
    geared down. I am creating the system from scratch and so have a
    clean slate to work with. There will only be 2 motors in close
    proximity to each other.

    Just so you know the big picture, I am trying to create a 2 legged
    walking robot. There will be 2 motors for ankle control, 2 for the
    knee and 3 for the hip. The whole robot will be ablout 2' tall when
    standing at full height so the distance between the controllers and
    motors will not be too great...

    Thanks again.

    Andy



    --- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...> wrote:
    > At 09:18 AM 7/24/03 +0000, thor69uk wrote:
    > >Bruce,
    > >
    > >Thanks for getting back to me.
    > >
    > >There will be 14 motors in all and all of them will be 8.4V and 1
    amp
    > >running current.
    > >
    > >Can you suggest any other ways or do you need more info...
    > >
    > >Thanks again,
    > >
    > >Andy.
    > Hi Andy -
    >
    > Are these AC powered or DC powered motors ? Are they servo motors,
    stepper
    > motors, or some other type ? Are they in close proximity to one
    another, or
    > are there great distances between the motors and/or the controller
    you
    > propose ?
    > Are you replacing an existing system, and if so, what type ?
    >
    > That should be a start towards an appropriate answer to your needs.
    >
    > Regards,
    >
    > Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-24 14:15
    At 11:09 AM 7/24/03 +0000, thor69uk wrote:
    >Bruce,
    >
    >The motors are normal hobby DC motors. They will be quite severly
    >geared down. I am creating the system from scratch and so have a
    >clean slate to work with. There will only be 2 motors in close
    >proximity to each other.
    >
    >Just so you know the big picture, I am trying to create a 2 legged
    >walking robot. There will be 2 motors for ankle control, 2 for the
    >knee and 3 for the hip. The whole robot will be ablout 2' tall when
    >standing at full height so the distance between the controllers and
    >motors will not be too great...
    >
    >Thanks again.
    >
    >Andy
    Andy -

    When you say "DC hobby motors" are you speaking of R/C servos ?

    If not, are you speaking of brush or brush-less DC motors ?

    If so, the solution if fairly trivial, by use of a serial servo controller
    board shown below:

    Here is one that is complete or may be purchased as a kit:
    http://www.seetron.com/ssc.htm

    This is more of a DIY version using a PIC:
    http://www.rentron.com/SerialServo.htm

    You also may want to review this web page from Lynxmotion:
    http://www.lynxmotion.com/

    Regards,

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-24 14:34
    At 11:09 AM 7/24/03 +0000, thor69uk wrote:
    >Bruce,
    >
    >The motors are normal hobby DC motors. They will be quite severly
    >geared down. I am creating the system from scratch and so have a
    >clean slate to work with. There will only be 2 motors in close
    >proximity to each other.
    >
    >Just so you know the big picture, I am trying to create a 2 legged
    >walking robot. There will be 2 motors for ankle control, 2 for the
    >knee and 3 for the hip. The whole robot will be ablout 2' tall when
    >standing at full height so the distance between the controllers and
    >motors will not be too great...
    >
    >Thanks again.
    >
    >Andy

    Andy -

    I wasn't careful enough when I read your latest post. Here is a bi-pedal robot
    kit which only uses two servos:
    http://robotstore.com/catalog/display.asp?pid=214

    My recommendation would be to start small, and work your way up to a larger
    robot. Many of the parts can follow forward as the robot "grows".

    Bruce
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