[comp.robotics] Inclinometers

mack@frc2.frc.ri.cmu.edu (Clark McDonald) (10/18/90)

>I wonder if any kind of acceleration, even increased acceleration to
>make it up the incline, would cause trouble if a "pendelum" is used?

Well, a few years ago now, I had the chance to disassemble an 
inclinometer that was sold to us (for quite a few US $$$) by a 
reputable well-known firm that I will leave unnamed.  After 
removing the cover of this discus-shaped device, I found three 
things inside it:

          1)  A potentiometer

          2)  A fishing weight, attached to the pot's shaft

          3)  Silicone Damping Fluid -- that's right, the entire 
              gizmo was flooded with the damping fluid.  This goo 
              is the sticky stuff that kept the weight from rebounding
              on acceleration, jolts, etc.

You can purchase silicone damping fluid at electronics parts houses.  

It is used to damp the cueing action on those old fashioned record 
turntable arms.  It comes in various weights.

As an aside, I have since duplicated this setup and gotten great
results.  At least at the slooowww speeds my home-brew robots move at.


--mack


--
Clark (Mack) McDonald                 ARPA:  mack@frc.ri.cmu.edu
Field Robotics Center
Carnegie Mellon University                (412) 268-6555
Pittsburgh, PA 15213