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controlling servos with STAMP micros — Parallax Forums

controlling servos with STAMP micros

ArchiverArchiver Posts: 46,084
edited 2003-05-01 03:49 in General Discussion
Hi,
I am trying to convert a monster truck (rc car), into a rc-less toy,
using the STAMP micros, however i need to have a driving mechanism
in place to move this car around, knowing that these cars operate at
27 or 47 Mhz range, i was wondering if there is any way that i could
connect the micro to the receiver's antenaa and be producing those
pulses directly to the receiver's circuit. first i probably should
capture the control pulses from the controller then be able to
implement them on the micro. also i know that the micro can produce
pulses in kHz range only. how to overcome this? does this strategy
sound sane? any suggestions or corections?

Thank You
Souhail

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-04-30 20:41
    Why don't you use the Pololu Micro Dual serial motor controller? Found
    here: http://www.pololu.com/products/pololu/0401
    You just hook up the existing motors to it and then figure out your R/C
    stuff.

    -Mike

    Original Message
    From: s4souhail [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gSzfi_JQOpOQq0_hhky7LEmbcRwOpdGZRG2R45UwkWbpN5lYXi72vmsUnQCelQbjDuNQNNYE0XNYhg]s4souhail@y...[/url
    Sent: Wednesday, April 30, 2003 1:28 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] controlling servos with STAMP micros

    Hi,
    I am trying to convert a monster truck (rc car), into a rc-less toy,
    using the STAMP micros, however i need to have a driving mechanism
    in place to move this car around, knowing that these cars operate at
    27 or 47 Mhz range, i was wondering if there is any way that i could
    connect the micro to the receiver's antenaa and be producing those
    pulses directly to the receiver's circuit. first i probably should
    capture the control pulses from the controller then be able to
    implement them on the micro. also i know that the micro can produce
    pulses in kHz range only. how to overcome this? does this strategy
    sound sane? any suggestions or corections?

    Thank You
    Souhail


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  • ArchiverArchiver Posts: 46,084
    edited 2003-04-30 21:11
    Some of the motors they use on the RC cars can pull alot of current when the
    motor is stalled. I would suggest hacking the board that came with the car
    and supplying the control pulses or whatever in place of the receiver. This
    way you keep the motor control circuit that you know already works with
    those motors.


    Original Message


    > Why don't you use the Pololu Micro Dual serial motor controller? Found
    > here: http://www.pololu.com/products/pololu/0401
    > You just hook up the existing motors to it and then figure out your R/C
    > stuff.

    > I am trying to convert a monster truck (rc car), into a rc-less toy,
    > using the STAMP micros, however i need to have a driving mechanism
    > in place to move this car around, knowing that these cars operate at
    > 27 or 47 Mhz range, i was wondering if there is any way that i could
    > connect the micro to the receiver's antenaa and be producing those
    > pulses directly to the receiver's circuit. first i probably should
    > capture the control pulses from the controller then be able to
    > implement them on the micro. also i know that the micro can produce
    > pulses in kHz range only. how to overcome this? does this strategy
    > sound sane? any suggestions or corections?
  • ArchiverArchiver Posts: 46,084
    edited 2003-04-30 21:34
    The 27 or 49MHz signal is decoded into a pulse width that is much lower
    in frequency. You want to connect the micro to the decoded receive
    inputs, not the antenna inputs.

    You can use, among other things, a PAK-VIII
    (http://www.al-williams.com/pak8.htm) to control a servo (actually up to
    8 servos). Have a look at the examples we provide for that chip (for
    example http://www.al-williams.com/servobot.htm) to get an idea about
    how that works.

    Hope that helps.

    Regards,

    Al Williams
    AWC
    * Floating point A/D
    http://www.al-williams.com/awce/pak9.htm



    >
    Original Message
    > From: s4souhail [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=mO0kKIMVyvmJwTpxh-3EoekvGIz2nZ-OBWJ-mnvZp16_wAiqnIM7vceVPUsHHgPmpsYMYR1UafFuqg]s4souhail@y...[/url
    > Sent: Wednesday, April 30, 2003 12:28 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] controlling servos with STAMP micros
    >
    >
    > Hi,
    > I am trying to convert a monster truck (rc car), into a rc-less toy,
    > using the STAMP micros, however i need to have a driving mechanism
    > in place to move this car around, knowing that these cars operate at
    > 27 or 47 Mhz range, i was wondering if there is any way that i could
    > connect the micro to the receiver's antenaa and be producing those
    > pulses directly to the receiver's circuit. first i probably should
    > capture the control pulses from the controller then be able to
    > implement them on the micro. also i know that the micro can produce
    > pulses in kHz range only. how to overcome this? does this strategy
    > sound sane? any suggestions or corections?
    >
    > Thank You
    > Souhail
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the
    > Subject and Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to
    > http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-05-01 01:34
    Hi,So you are saying instead of connecting the micro to the decoder, i should
    connect it the circuit that comes after the decoder, which controllers the
    motors. (bypass the decoder)?
    Thanks

    Rodent <daweasel@s...> wrote:Some of the motors they use on the RC cars
    can pull alot of current when the
    motor is stalled. I would suggest hacking the board that came with the car
    and supplying the control pulses or whatever in place of the receiver. This
    way you keep the motor control circuit that you know already works with
    those motors.


    Original Message


    > Why don't you use the Pololu Micro Dual serial motor controller? Found
    > here: http://www.pololu.com/products/pololu/0401
    > You just hook up the existing motors to it and then figure out your R/C
    > stuff.

    > I am trying to convert a monster truck (rc car), into a rc-less toy,
    > using the STAMP micros, however i need to have a driving mechanism
    > in place to move this car around, knowing that these cars operate at
    > 27 or 47 Mhz range, i was wondering if there is any way that i could
    > connect the micro to the receiver's antenaa and be producing those
    > pulses directly to the receiver's circuit. first i probably should
    > capture the control pulses from the controller then be able to
    > implement them on the micro. also i know that the micro can produce
    > pulses in kHz range only. how to overcome this? does this strategy
    > sound sane? any suggestions or corections?




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    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-05-01 03:49
    *IF* you have incremental steering and speed, you can disconnect the
    receiver and feed the control pulses to the motor controllers directly. If
    this is a cheap RC car with simple forward / reverse / left / right control
    (the steering and speed are either on or off,), it will be different.

    Original Message

    > Hi,So you are saying instead of connecting the micro to the decoder, i
    should connect it the circuit that comes after the decoder, which
    controllers the motors. (bypass the decoder)?

    Some of the motors they use on the RC cars can pull alot of current when the
    > motor is stalled. I would suggest hacking the board that came with the car
    > and supplying the control pulses or whatever in place of the receiver.
    This
    > way you keep the motor control circuit that you know already works with
    > those motors.
    >
    >
    >
    Original Message
    >
    >
    > > Why don't you use the Pololu Micro Dual serial motor controller? Found
    > > here: http://www.pololu.com/products/pololu/0401
    > > You just hook up the existing motors to it and then figure out your R/C
    > > stuff.
    >
    > > I am trying to convert a monster truck (rc car), into a rc-less toy,
    > > using the STAMP micros, however i need to have a driving mechanism
    > > in place to move this car around, knowing that these cars operate at
    > > 27 or 47 Mhz range, i was wondering if there is any way that i could
    > > connect the micro to the receiver's antenaa and be producing those
    > > pulses directly to the receiver's circuit. first i probably should
    > > capture the control pulses from the controller then be able to
    > > implement them on the micro. also i know that the micro can produce
    > > pulses in kHz range only. how to overcome this? does this strategy
    > > sound sane? any suggestions or corections?
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
    >
    > Do you Yahoo!?
    > The New Yahoo! Search - Faster. Easier. Bingo.
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    > To UNSUBSCRIBE, just send mail to:
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