[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>
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