Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!masscomp!ocpt!tsdiag!davet
From: davet@tsdiag.ccur.com (Dave Tiller N2KAU)
Newsgroups: sci.electronics
Subject: Re: X-Y detection of moving metal ball?
Message-ID: <1510@tsdiag.ccur.com>
Date: 5 Apr 91 15:35:28 GMT
References: <1225@telesoft.com>
Organization: Concurrent Computer Corp. Oceanport NJ
Lines: 28

In article <1225@telesoft.com> rlk@telesoft.com (Bob Kitzberger @sation) writes:
-
-Hi All,
-
-I've got a 'pet project' problem that is generating a lot of ideas among
-colleagues at work, but NO concrete solutions.  (concrete solution ==
-part numbers and source for parts ;-)  
-
-And no, this isn't a school project ;-)
-
-Problem: I want to detect the X and Y coordinates of a metal ball bearing
-(magnetized or not) in motion within a box.  The data collection must
-occur in a fashion that allows me to derive the velocity vector of the ball
-bearing in the X-Y plane.  The size of the box is approximately one foot by one
-foot.  Also, I should mention that the detection must occur in real-time.


Instead of looking across the box, try looking up through the bottom.
Affix phototransistors on the bottom of the box (made of plexiglas) so
that when the ball rolls over the sensor, it temporarily blocks the light.
This eliminates several of the problems associated with the side-looking
method, such as multiple signals when the ball is near the side opposite the
sensors.
-- 
David E. Tiller         davet@tsdiag.ccur.com  | Concurrent Computer Corp.
FAX:  201-870-5952      Ph: (201) 870-4119 (w) | 2 Crescent Place, M/S 117
UUCP: ucbvax!rutgers!petsd!tsdiag!davet        | Oceanport NJ, 07757
ICBM: 40 16' 52" N      73 59' 00" W           | N2KAU @ NN2Z