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CR Servo Question — Parallax Forums

CR Servo Question

NWCCTVNWCCTV Posts: 3,629
edited 2013-10-19 09:21 in General Discussion
I was looking on EBay the other day and seen several dual horned servos but for the life of me I can not remember what they are called and sure enough I can not find them again. I beed the continuous rotation servos that are used in Biped type walers, etc. with horn attachment on both sides. Any suggestions?

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-10-18 17:19
    NWCCTV wrote: »
    I was looking on EBay the other day and seen several dual horned servos but for the life of me I can not remember what they are called and sure enough I can not find them again. I beed the continuous rotation servos that are used in Biped type walers, etc. with horn attachment on both sides. Any suggestions?

    Many, if not most servos come with this type of horn. Though they might not be as long as the horns you have in mind. Some hobby shops sell just the horns. You need to make sure you get the right kind of horn to match the brand of your servo. Different brands have different numbers of spines on the servo output shafts.

    Your title has "CR Servo". Most servos are not continuous rotation but can usually easily be modified to be so. This servo from HobbyKing is one of the easiest servos I've found to convert to CR. It also has a double horn.

    I think the double horns are often used with RC airplanes' ailerons. A lot of the servos I've seen for sale include a picture of the horns which come with the servo.

    How strong does your servo need to be?
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-10-18 17:25
    Apparently one name for that type of servo horn is a double arm. Here are some more.
  • NWCCTVNWCCTV Posts: 3,629
    edited 2013-10-18 18:02
    @Duane Degn, This is what I was referring to. They have the Horn connection on both sides. I found these ones but need them to be at least 10Kg on the torque.
  • W9GFOW9GFO Posts: 4,010
    edited 2013-10-18 18:23
    Walkers don't use CR servos. Maybe you are thinking of the Dynamixel servos?

    I also see that Trossen has some cheaper analog ones.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-10-18 18:41
    HobbyKing sells some "robot servos". I know Rich isn't a HK fan but I haven't had any issues with any of my many HK orders.

    The servos listed don't really have two horns but rather a pivot point on one side. I used Lego turntables to add a pivot point to the back of my servos in my Popsicle stick hexapod.
  • NWCCTVNWCCTV Posts: 3,629
    edited 2013-10-18 18:59
    Walkers don't use CR servos.
    Yea, I am aware of this. I was just using it as an example for the dual shafts. The ones at HobbyKing look to be exactly what I need. Thanks Duane.
  • ercoerco Posts: 20,256
    edited 2013-10-19 09:21
    Those double-shaft servos are nice for high loads, like a robot arm or a multijoint walker leg. The one Andy linked to says "high speed". Personally, I'd always choose lower speed, higher torque for durability, like this one: http://www.ebay.com/itm/13KG-0-23sec-Metal-RC-Digital-Robot-Servo-Double-shaft-/130493651093?pt=Radio_Control_Parts_Accessories&hash=item1e62071895

    Digital servos can be usually swapped in for analog servos, but there are some differences to be aware of, higher power requirements among them. http://www.futaba-rc.com/servos/digitalservos.pdf
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