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!!!urgent!!!urgent!!!urgent___please_help!!! — Parallax Forums

!!!urgent!!!urgent!!!urgent___please_help!!!

ArchiverArchiver Posts: 46,084
edited 2001-01-12 02:35 in General Discussion
···Friends, i am totally in a mess. I have an important project assignment (a final project for graduation) and i fount out that the stepper motor i am using cannot supply the required torque. I am thinking to use a Hitec HS-715BB servo now (able to make three full revolutions) but i·don't know whether i can control it with my BS2. Anyone having an idea please contact me urgently, because i do not have time (last three days, and there is still much work to do.

··· Any help will be appreciated, thanx in advance.

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-01-11 13:47
    I am no pro, but controlling the servo with a bs2 is relatively simple. You will use the "pulsout" command to generate the control signal. A pulsout value of 750 should be neutral or close to it. When the pulsout value rises above neutral (+-750) the servo will go forward and below neutral the servo will reverse. I recommend that you go to·www.Parallaxinc.com·and download the Boebot manual.· This manual has the instructions you need.

    Jeff

    Original Message
    From: Osman Burak Celebi
    To: basicstamps@egroups.com
    Sent: Thursday, January 11, 2001 4:46 AM
    Subject: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!

    ···Friends, i am totally in a mess. I have an important project assignment (a final project for graduation) and i fount out that the stepper motor i am using cannot supply the required torque. I am thinking to use a Hitec HS-715BB servo now (able to make three full revolutions) but i·don't know whether i can control it with my BS2. Anyone having an idea please contact me urgently, because i do not have time (last three days, and there is still much work to do.

    ··· Any help will be appreciated, thanx in advance.
  • ArchiverArchiver Posts: 46,084
    edited 2001-01-11 17:45
    but the problem is; the servo i want to use is not an ordinary standard servo. It is a special sail winch that can return 3.5 turns

    Original Message
    From: Jeff Mitchell [noparse][[/noparse]mailto:EL-JEFE@PRODIGY.NET]
    Sent: Thursday, January 11, 2001 3:47 PM
    To: basicstamps@egroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!

    I am no pro, but controlling the servo with a bs2 is relatively simple. You will use the "pulsout" command to generate the control signal. A pulsout value of 750 should be neutral or close to it. When the pulsout value rises above neutral (+-750) the servo will go forward and below neutral the servo will reverse. I recommend that you go to·www.Parallaxinc.com·and download the Boebot manual.· This manual has the instructions you need.

    Jeff

    Original Message
    From: Osman Burak Celebi
    To: basicstamps@egroups.com
    Sent: Thursday, January 11, 2001 4:46 AM
    Subject: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!

    ···Friends, i am totally in a mess. I have an important project assignment (a final project for graduation) and i fount out that the stepper motor i am using cannot supply the required torque. I am thinking to use a Hitec HS-715BB servo now (able to make three full revolutions) but i·don't know whether i can control it with my BS2. Anyone having an idea please contact me urgently, because i do not have time (last three days, and there is still much work to do.

    ··· Any help will be appreciated, thanx in advance.
  • ArchiverArchiver Posts: 46,084
    edited 2001-01-11 20:52
    Jeff might be right anyway.

    The Hitec HS-715BB that you mention is a 90 degree servo
    (http://www.hitecrcd.com/Catalog/Servos/HS-715.htm).

    Did you mean that you are considering the Hitec HS-725BB
    (http://www.hitecrcd.com/Catalog/Servos/HS-725.htm)?

    In either case, it seems that the servo would respond to standard servo
    pulse trains. Unfortunately, I did not find a manual for this servo on
    Hitec's web site.

    Are you using this servo un-modified (limited to the servo's mechanical
    rotation of 3.5 turns) or have you modified it for continuous rotation?

    You might consider contacting Hitec directly in you need servo specific
    help. Their page http://www.hitecrcd.com/ETC/ask_hitec.html has both e-mail
    and phone numbers.

    Regards,
    Daniel McGlothin



    Original Message
    From: Osman Burak Celebi [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=MC5xZ9CDv0JIVW_wL5nr2x0dD-uiPOmiBB6llVmiysAjKYjjItYV8wj61qmbc1h69BqNWLgWihpSQ7IpGmxU4Fg]obcelebi@s...[/url
    Sent: Thursday, January 11, 2001 12:46 PM
    To: basicstamps@egroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    but the problem is; the servo i want to use is not an ordinary standard
    servo. It is a special sail winch that can return 3.5 turns
    Original Message
    From: Jeff Mitchell [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gUioj2UDzNGY2rQ8Bc-ttmuMonqv3Q_DqmbSSyKOX__wliJBT60bCg0zelqvy0R0sFHNnkiUQ5-dNtg6WRs]EL-JEFE@P...[/url
    Sent: Thursday, January 11, 2001 3:47 PM
    To: basicstamps@egroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    I am no pro, but controlling the servo with a bs2 is relatively simple. You
    will use the "pulsout" command to generate the control signal. A pulsout
    value of 750 should be neutral or close to it. When the pulsout value rises
    above neutral (+-750) the servo will go forward and below neutral the servo
    will reverse. I recommend that you go to www.Parallaxinc.com and download
    the Boebot manual. This manual has the instructions you need.

    Jeff

    Original Message
    From: Osman Burak Celebi
    To: basicstamps@egroups.com
    Sent: Thursday, January 11, 2001 4:46 AM
    Subject: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    Friends, i am totally in a mess. I have an important project assignment
    (a final project for graduation) and i fount out that the stepper motor i am
    using cannot supply the required torque. I am thinking to use a Hitec
    HS-715BB servo now (able to make three full revolutions) but i don't know
    whether i can control it with my BS2. Anyone having an idea please contact
    me urgently, because i do not have time (last three days, and there is still
    much work to do.

    Any help will be appreciated, thanx in advance.
  • ArchiverArchiver Posts: 46,084
    edited 2001-01-11 21:27
    oops... sorry. Yes, i have a Hitec HS-725BB and i am still waiting reply
    from Hitec. Half an hour ago we made some experiments on the servo and
    solved the control problem. But there is still one thing i cannot
    understand. If no program is loaded on BS2, the servo starts revolution
    infinitely, but when i write a program to control its position, it obeys the
    3.5 revolution limit and stucks at the end position.

    And i have one more question about servos (it may be a little newbie
    question). When the servo finishes its work (this one is a HS300BB standard
    servo but also the new one does it) that is when it reaches the final
    position i give, it tries to move in small strokes and it ruins the
    position. What can i do to totally stop a servo in the middle of a big
    program (in the robot we are building the standard servo does a subroutine
    in several positions)?

    Thanx for your advices and help.
    Osman Burak Celebi

    Original Message
    From: D. Daniel McGlothin [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=mDqkAVnnUlTDvJc-Mp8sp51inwpVrxAJpPM6RUmSMO68daa7U6xQEgvPdK_TvZQWupozWtWW-vKs]ddm@r...[/url
    Sent: Thursday, January 11, 2001 10:52 PM
    To: basicstamps@egroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    Jeff might be right anyway.

    The Hitec HS-715BB that you mention is a 90 degree servo
    (http://www.hitecrcd.com/Catalog/Servos/HS-715.htm).

    Did you mean that you are considering the Hitec HS-725BB
    (http://www.hitecrcd.com/Catalog/Servos/HS-725.htm)?

    In either case, it seems that the servo would respond to standard servo
    pulse trains. Unfortunately, I did not find a manual for this servo on
    Hitec's web site.

    Are you using this servo un-modified (limited to the servo's mechanical
    rotation of 3.5 turns) or have you modified it for continuous rotation?

    You might consider contacting Hitec directly in you need servo specific
    help. Their page http://www.hitecrcd.com/ETC/ask_hitec.html has both e-mail
    and phone numbers.

    Regards,
    Daniel McGlothin



    Original Message
    From: Osman Burak Celebi [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=EntGWrMVDO8DcsRydyuArOJ8kkAUTfsSu4gWsOrXaVcYI6pItQUziRAg-frIH5cQaenQphuk70Fdz5zU-VL0dM31]obcelebi@s...[/url
    Sent: Thursday, January 11, 2001 12:46 PM
    To: basicstamps@egroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    but the problem is; the servo i want to use is not an ordinary standard
    servo. It is a special sail winch that can return 3.5 turns
    Original Message
    From: Jeff Mitchell [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=C9OgQVqviAvsg6O0Gp__96DIfAemaaumGaeBaNH-wF8GLQeP1gUTsXq55yUBbsCLhsU7UHLs5sWi]EL-JEFE@P...[/url
    Sent: Thursday, January 11, 2001 3:47 PM
    To: basicstamps@egroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    I am no pro, but controlling the servo with a bs2 is relatively simple. You
    will use the "pulsout" command to generate the control signal. A pulsout
    value of 750 should be neutral or close to it. When the pulsout value rises
    above neutral (+-750) the servo will go forward and below neutral the servo
    will reverse. I recommend that you go to www.Parallaxinc.com and download
    the Boebot manual. This manual has the instructions you need.

    Jeff

    Original Message
    From: Osman Burak Celebi
    To: basicstamps@egroups.com
    Sent: Thursday, January 11, 2001 4:46 AM
    Subject: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!


    Friends, i am totally in a mess. I have an important project assignment
    (a final project for graduation) and i fount out that the stepper motor i am
    using cannot supply the required torque. I am thinking to use a Hitec
    HS-715BB servo now (able to make three full revolutions) but i don't know
    whether i can control it with my BS2. Anyone having an idea please contact
    me urgently, because i do not have time (last three days, and there is still
    much work to do.

    Any help will be appreciated, thanx in advance.
  • ArchiverArchiver Posts: 46,084
    edited 2001-01-11 23:14
    If there is no program, the Stamp pin floats (it is an input) and so I would
    think a pulldown resistor would stop that rotation.

    As for sticking at the end... are you in fact sending continuous pulse
    trains?

    To "center" it -- assuming it works like all the servos I've seen (I haven't
    used your model), you'd write something like:

    again:
    PULSOUT 0,750 ' 1500uS
    PAUSE 20 ' 20mS -- might be your processing in here instead of
    pause
    goto again

    Note you have to keep sending it pulses.

    Al Williams
    AWC
    *Control 8 servos: http://www.al-williams.com/awce/pak8.htm


    >
    Original Message
    > From: Osman Burak Celebi [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=a-ifSI_dTIDF00cx84Fr97qg_TqpkQ3kzOZAqKke605LuXNe_7vneg8Cmu3ONwhvsI1sMB-oMPCzWJyKK_OC]obcelebi@s...[/url
    > Sent: Thursday, January 11, 2001 3:28 PM
    > To: basicstamps@egroups.com
    > Subject: RE: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!
    >
    >
    > oops... sorry. Yes, i have a Hitec HS-725BB and i am still
    > waiting reply
    > from Hitec. Half an hour ago we made some experiments on the servo and
    > solved the control problem. But there is still one thing i cannot
    > understand. If no program is loaded on BS2, the servo starts revolution
    > infinitely, but when i write a program to control its position,
    > it obeys the
    > 3.5 revolution limit and stucks at the end position.
    >
    > And i have one more question about servos (it may be a little newbie
    > question). When the servo finishes its work (this one is a
    > HS300BB standard
    > servo but also the new one does it) that is when it reaches the final
    > position i give, it tries to move in small strokes and it ruins the
    > position. What can i do to totally stop a servo in the middle of a big
    > program (in the robot we are building the standard servo does a subroutine
    > in several positions)?
    >
    > Thanx for your advices and help.
    >
    > Osman Burak Celebi
    >
    >
    Original Message
    > From: D. Daniel McGlothin [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=I2ZyyUIcUC0z_NMFRqvjLPfNdl6VbTeFefxVLvFd-mPcJlfEWDOXELeTPggameaY1MFJan999UMGSA]ddm@r...[/url
    > Sent: Thursday, January 11, 2001 10:52 PM
    > To: basicstamps@egroups.com
    > Subject: RE: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!
    >
    >
    > Jeff might be right anyway.
    >
    > The Hitec HS-715BB that you mention is a 90 degree servo
    > (http://www.hitecrcd.com/Catalog/Servos/HS-715.htm).
    >
    > Did you mean that you are considering the Hitec HS-725BB
    > (http://www.hitecrcd.com/Catalog/Servos/HS-725.htm)?
    >
    > In either case, it seems that the servo would respond to standard servo
    > pulse trains. Unfortunately, I did not find a manual for this servo on
    > Hitec's web site.
    >
    > Are you using this servo un-modified (limited to the servo's mechanical
    > rotation of 3.5 turns) or have you modified it for continuous rotation?
    >
    > You might consider contacting Hitec directly in you need servo specific
    > help. Their page http://www.hitecrcd.com/ETC/ask_hitec.html has
    > both e-mail
    > and phone numbers.
    >
    > Regards,
    > Daniel McGlothin
    >
    >
    >
    >
    Original Message
    > From: Osman Burak Celebi [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=a-ifSI_dTIDF00cx84Fr97qg_TqpkQ3kzOZAqKke605LuXNe_7vneg8Cmu3ONwhvsI1sMB-oMPCzWJyKK_OC]obcelebi@s...[/url
    > Sent: Thursday, January 11, 2001 12:46 PM
    > To: basicstamps@egroups.com
    > Subject: RE: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!
    >
    >
    > but the problem is; the servo i want to use is not an ordinary standard
    > servo. It is a special sail winch that can return 3.5 turns
    >
    Original Message
    > From: Jeff Mitchell [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=UYpIFBOCBh8R3qaHHIc0ktlW0FD9bCM53MhRb1oZAe_VAjZpb4qPHsR9X4gwlNieeipXDZ-YdTyc2ko9fw]EL-JEFE@P...[/url
    > Sent: Thursday, January 11, 2001 3:47 PM
    > To: basicstamps@egroups.com
    > Subject: Re: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!
    >
    >
    > I am no pro, but controlling the servo with a bs2 is relatively
    > simple. You
    > will use the "pulsout" command to generate the control signal. A pulsout
    > value of 750 should be neutral or close to it. When the pulsout
    > value rises
    > above neutral (+-750) the servo will go forward and below neutral
    > the servo
    > will reverse. I recommend that you go to www.Parallaxinc.com and download
    > the Boebot manual. This manual has the instructions you need.
    >
    > Jeff
    >
    >
    Original Message
    > From: Osman Burak Celebi
    > To: basicstamps@egroups.com
    > Sent: Thursday, January 11, 2001 4:46 AM
    > Subject: [noparse][[/noparse]basicstamps] !!!URGENT!!!URGENT!!!URGENT___PLEASE_HELP!!!
    >
    >
    > Friends, i am totally in a mess. I have an important project assignment
    > (a final project for graduation) and i fount out that the stepper
    > motor i am
    > using cannot supply the required torque. I am thinking to use a Hitec
    > HS-715BB servo now (able to make three full revolutions) but i don't know
    > whether i can control it with my BS2. Anyone having an idea please contact
    > me urgently, because i do not have time (last three days, and
    > there is still
    > much work to do.
    >
    > Any help will be appreciated, thanx in advance.
    >
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-01-12 02:35
    here's a new view on some reasons why your servo does some of the
    things you're reporting.....

    first, when you power up a R/C style servo, it immediately expects to
    see 1-2 millisecond pulses coming to the pwm wire. a pulse shorter
    than 1.5 milliseconds tells the servo to go one direction, a pulse
    longer than 1.5 milliseconds tells the servo to go the other way.
    when you power it on without any program loaded and running on your
    basic stamp to tell it where to go, the servo immediately assumes
    that it is getting a 0 millisecond pulse and it immediately pegs to
    one side.

    i think the easiest way to run a servo connected to a basic stamp is
    by using a serial servo controller. that way you can tell the servo
    to go to position x and stay there until you tell it to go to another
    position. also, the serial servo controller automatically sends the
    servo a 1.5 millisecond pulse to center it upon power up. since you
    have less than 3 days to finish your project, getting one is probably
    impractical.

    i have had trouble with hitec servos recently. i just put together a
    6 legged robot walker using 12 hitec hs300 servos. about 6 of the 12
    servos were extremely inaccurate in their center positions (not
    anywhere near the center of the range of motion) and they were very
    jerky when they moved. some of them just wouldn't even center
    properly. they would attempt to center upon power up but they would
    jerk back and forth and never find a stable home position. i ended
    up ripping all of them out and buying 300 bucks worth of good ball
    bearing servos of a different brand and was immediately relieved. i
    don't know what the higher end servos from hitec are like, but i can
    say that the low end stuff is poor. there is a BIG difference
    between cheap servos and INEXPENSIVE servos. the particular brand i
    switched to was HOBBICO. the hitec hs300 servo sells for about 15
    bucks apiece and has only 1 crummy nylon bushing supporting the
    output shaft. HOBBICO's 15 dollar servo has dual ball bearings on
    it's output shaft and more torque and a faster rotation speed.

    good luck with your project.
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