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Convert Parallax Standard Servos to Continuous Rotation? — Parallax Forums

Convert Parallax Standard Servos to Continuous Rotation?

ScopeScope Posts: 417
edited 2012-05-27 14:21 in General Discussion
Hello,

I did a search at these forums and read some info which helped a little but didn't fully answer my question:
Can I convert my 2 Parallax standard servos to continuous rotation?

I realize there will be a stop sleeve (?) that I'll have to modify but I'm unsure about the potentiometer.

Thanks,

Brad

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-27 14:07
    Depending on where you're going to use the servo, you can just let the pot hang outside the servo by having its wire exit through the same gap as the other wires (I sometimes enlarge the gap).

    There's often a small screw holding the pot in place. Once you remove the screw you can push the pot out from above (assuming you've also removed the final gear).

    Parallax's CR servos use a trim pot instead of the normal pot. The trim pot is soldered directly to the servos PCB. A hole has been drilled through the servo case to allow the trim pot to be adjusted. If you wanted, you could do something similar with your servo and keep the pot inside the case and adjust the pot through the case.

    It's best to keep some sort of pot connected to the servo so you can adjust its zero (stopped) position. It's possible to just use two resistors instead of a pot and adjust the zero position in software.

    The final gear of the servo has a plastic stop that will need to be cut away.

    If the servo has the motor directly soldered to the PCB, let me know. There are some tricks to taking apart a Parallax servo that aren't usually required with other servos.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-27 14:21
    Duane Degn wrote: »
    If the servo has the motor directly soldered to the PCB, let me know. There are some tricks to taking apart a Parallax servo that aren't usually required with other servos.

    In post #5 of this thread is a picture of an opened Parallax servo. I don't know if Rayman broke the PCB on his Parallax servo on purpose or not.

    I found by pushing down on the motor from above on its pinion gear and pulling on the PCB at the same time, I was able to remove the motor/PCB combination in one piece.

    You need to remove the PCB in order to gain access to the potentiometer.
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