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An Interesting Servo Modification

[Editors Note: Here is an interesting twist on the old servo modification that is in wide use among roboteers all around the world. I thought it was interesting to see that there are always improvments to be made! I especially liked the way Jack reuses the existing pot for feedback.]

----- Original Message -----

From: Jack  McIntosh <McIntosh@umatilla.k12.or.us>

To: <kevinro@nwlink.com>

Sent: Sunday, April 09, 2000 10:41 AM

Subject: Modifying a servo

> Dear Kevin,
>   I read and used your article on modifying a servo.  We used the
> process for a high school technology class to build a small-bot and
> program using the Basic Stamp.  We encountered some confusion in
> programing in that no two servo's seemed to have the same stop setting.
>    In reading about a new PIC called the OOPIC, someone said that they
> had wired a pot on the exterior of the servo so that they could adjust
> the stop position.  This prompted me to see if it would work to just
> modify the pot inside the servo and make it adjustable thus keeping the
> resistance the same as what the servo came with origionally.  I sawed
> the stem of   the servo and cut a slot in the end to accommodate a small
> screwdriver.  I then bent the leads of the pot so that it points
> sideways.  I then drilled a hole in the case to insert the screwdriver
> for adjustment. As an alternative, I also purchased a small multiturn
> pot that could be installed for finer tuning of the pot.  I feel that
> either of of these solutions will help my students in that the center or
> stop postion can be set the same so that one value can be used for
> center and make the programing easier.  I am also excited about trying
> the OOPIC as there are 31 I/O that can be used.
>   I am enclosing  pictures of my modifications.  I am also enclosing a
> picture of the robot that my students made and programmed.   You may have
> discovered all this out already, but I felt it was worth mention.
>   I also enjoyed your article on tools.
>
> Jack McIntosh
> Umatilla High School
> Umatilla, Or  97882
> E-mail   McIntosh@umatilla.k12.or.us

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