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Boe-Bot Servos

ArchiverArchiver Posts: 46,084
edited 2004-02-09 23:34 in General Discussion
I bought the Parallax Boe-Bot special and decided to play with it to learn a
little programming. It comes with the new updated servos. After I put it
together the RPM of the servos are not even close. I have to use a 500 pulse
time for one servo and a 820 pulse time for the other to get it to track
straight. I ended up shimming the servos so they "turn" to get it close... I
can now use 500/970 which is much better.

Is this a common problem with the new servos?

Hank Hagquist
HobbyTalk - http://www.hobbytalk.com
HobbyShopper - http://www.hobbyshopper.com

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-02-09 20:26
    1. The new servo's have a 'tuning' port, where
    you can insert a small phillips driver to set
    the 'do-nothing' point -- which should be
    1500 mS (or 750 on Pulsout).

    2. I also bought the special. I havn't gotten
    to the point of actually running it yet. Sigh.
    Thus even if both are properly set to the same
    'do-nothing' point, I don't know if they will
    be the same speed at the same Pulsout setting.
    More later, I'm sure.

    --- In basicstamps@yahoogroups.com, "Hank Hagquist" <hankster@h...>
    wrote:
    > I bought the Parallax Boe-Bot special and decided to play with it
    to learn a
    > little programming. It comes with the new updated servos. After I
    put it
    > together the RPM of the servos are not even close. I have to use a
    500 pulse
    > time for one servo and a 820 pulse time for the other to get it to
    track
    > straight. I ended up shimming the servos so they "turn" to get it
    close... I
    > can now use 500/970 which is much better.
    >
    > Is this a common problem with the new servos?
    >
    > Hank Hagquist
    > HobbyTalk - http://www.hobbytalk.com
    > HobbyShopper - http://www.hobbyshopper.com
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-09 20:57
    Both servos were zeroed at 750 pulsout. I just think one is faster then the
    other. Needing a 360 ms offset just seems kind of extreme.

    Hank Hagquist
    HobbyTalk - http://www.hobbytalk.com
    HobbyShopper - http://www.hobbyshopper.com




    Original Message
    From: "Allan Lane" <allan.lane@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, February 09, 2004 3:26 PM
    Subject: [noparse][[/noparse]basicstamps] Re: Boe-Bot Servos


    > 1. The new servo's have a 'tuning' port, where
    > you can insert a small phillips driver to set
    > the 'do-nothing' point -- which should be
    > 1500 mS (or 750 on Pulsout).
    >
    > 2. I also bought the special. I havn't gotten
    > to the point of actually running it yet. Sigh.
    > Thus even if both are properly set to the same
    > 'do-nothing' point, I don't know if they will
    > be the same speed at the same Pulsout setting.
    > More later, I'm sure.
    >
    > --- In basicstamps@yahoogroups.com, "Hank Hagquist" <hankster@h...>
    > wrote:
    > > I bought the Parallax Boe-Bot special and decided to play with it
    > to learn a
    > > little programming. It comes with the new updated servos. After I
    > put it
    > > together the RPM of the servos are not even close. I have to use a
    > 500 pulse
    > > time for one servo and a 820 pulse time for the other to get it to
    > track
    > > straight. I ended up shimming the servos so they "turn" to get it
    > close... I
    > > can now use 500/970 which is much better.
    > >
    > > Is this a common problem with the new servos?
    > >
    > > Hank Hagquist
    > > HobbyTalk - http://www.hobbytalk.com
    > > HobbyShopper - http://www.hobbyshopper.com
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-09 23:34
    Hi,

    The servos in your kit are different from (and better than) the servos
    described in the
    Robotics v1.5 text. There should have been a handout in your kit with
    instructions for the Parallax Continuous Rotation servos and other parts
    that have been changed (and improved). Look for "Robotics Appendix J"
    on www.parallax.com -> Downloads -> Educational Curriculum.

    Also available from the same page is the newly revised Robotics with the
    Boe-Bot v2.0 text, which supports all the new hardware and PBASIC 2.5.

    Regards, Andy

    Andy Lindsay
    Applications Engineer
    Parallax, Inc.

    Original Message
    From: Allan Lane [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=w0goqhm37BjcKo6I8_vwhmUS57EGrM76rZ6AvUaID5fMWPVXRl5D4WbFuraDxGezoxdEjdoEIIAljmNG8K5lqFRFhh0]allan.lane@h...[/url
    Sent: Monday, February 09, 2004 12:27 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Boe-Bot Servos


    1. The new servo's have a 'tuning' port, where
    you can insert a small phillips driver to set
    the 'do-nothing' point -- which should be
    1500 mS (or 750 on Pulsout).

    2. I also bought the special. I havn't gotten
    to the point of actually running it yet. Sigh.
    Thus even if both are properly set to the same
    'do-nothing' point, I don't know if they will
    be the same speed at the same Pulsout setting.
    More later, I'm sure.

    --- In basicstamps@yahoogroups.com, "Hank Hagquist" <hankster@h...>
    wrote:
    > I bought the Parallax Boe-Bot special and decided to play with it
    to learn a
    > little programming. It comes with the new updated servos. After I
    put it
    > together the RPM of the servos are not even close. I have to use a
    500 pulse
    > time for one servo and a 820 pulse time for the other to get it to
    track
    > straight. I ended up shimming the servos so they "turn" to get it
    close... I
    > can now use 500/970 which is much better.
    >
    > Is this a common problem with the new servos?
    >
    > Hank Hagquist
    > HobbyTalk - http://www.hobbytalk.com
    > HobbyShopper - http://www.hobbyshopper.com



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