Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!hp4nl!alchemy!nico From: nico@cs.ruu.nl (Nico Verwer) Newsgroups: comp.sys.atari.st Subject: Re: Obstinate Mice! Message-ID: <1991Mar14.103050.5074@cs.ruu.nl> Date: 14 Mar 91 10:30:50 GMT References: <3258@unccvax.uncc.edu> Organization: Utrecht University, Dept. of Computer Science Lines: 31 In mc4c+@andrew.cmu.edu (Mark Choi) writes: >when you try to move the mouse pointer to quickly in GEM, the mouse >starts to accelerate in the intended direction, then does an aboutface, >and heads in the other direction, and keeps doing this until you slow >down. This is quite annoying. I keep forgetting to check it in Mac mode >to see if it is GEM or the hardware controller. Probably lame GEM. I The problem is in the mouse itself. For both directions, there are two optical detectors. If you move the mouse, a small wheel with holes in it rotates along these detectors. If you move, say, left, then first detector A will detect a hole, and some time after that detector B. The time between the two pulses is determined by the speed of the movement. If you move the mouse to the right, first detector B will give a pulse, then detector A. A B detectors v v ##################wheel #O####O####O####O#holes Thus, pulses come in `packages' AB (left) or BA (right). But if you move too fast to the left, the circuitry in the mouse will combine the B pulse with the A pulse of the next `package', which results in a BA (right) package. This is similar to the stoboscope-effect which you sometimes see on TV: A rotating wheel appears to rotate in the wrong direction. The only solution is: Buy a better mouse. -- Nico Verwer | nico@cs.ruu.nl Dept. of Computer Science, University of Utrecht | phone: +31 30 533921 p.o. box 80.089, 3508 TB Utrecht, The Netherlands | fax: +31 30 513791