Newsgroups: comp.robotics
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From: epperson@adobe.com (Mark Epperson)
Subject: A sense of balance
Message-ID: <1993Jan31.072524.14704@adobe.com>
Sender: usenet@adobe.com (USENET NEWS)
Organization: Adobe Systems Incorporated
Date: Sun, 31 Jan 1993 07:25:24 GMT
Lines: 21

I have been thinking of a sensor for center-or-gravity (balance).  The general
idea is some form of rolling ball inside of a sphere or parabaloid.

   One idea is to use a thin plastic, a rolling magnet, and have a grid of 
magnus effect transistors glued to the underside to sense the magnetic flux. 
The grid would be scanned to get the values, convert to digital then 
interpolate to determine the exact location.

  A similar thing could be done with a LED hanging on a string and an array
of photo-diodes.

   Another idea is to put some form of conductive grid on the inside surface
and let the ball's weight complete the circuit (or change the capacitance). The
trouble with this is I can't thing of an easy way to make the grid.

   A similar approach has a grid of contact switches (button type) poking
through the surface, but this may not have the resolution I require.


What do you think?  How would you solve the problem(s)?
- Mark Epperson
