From: galt@dsd.es.com (Greg Alt - Perp) Subject: Re: Ultrasonic position detection Date: Tue, 1 Oct 91 21:44:58 GMT Organization: Evans & Sutherland Computer Corp., Salt Lake City, UT In article <1991Oct1.045624.25978@milton.u.washington.edu>, "Mark Anthony Brown;E200" writes: > Does anybody have any information as to the accuracy/operation of ultrasonic > trackers used in VR hardware? I've heard that the Mattel power glove uses > ultrasonics for tracking. The only other information I've got is on Sutherland's > original HMD, which used continuous wave ultrasonics or (shudder) a mechanical > arm attached to the user's head. Comparative performance information for > ultrasonics versus electromagnetic trackers would also be much appreciated. Well, I can give you some information about the powerglove ultrasonics... You can get position info acurate to 1/4 inch, but the ultrasonics must be aimed at the receivers (I think you have up to 90 degrees to play with). Also, with the powerglove, you can get informartion about 30 times a second. I think the electromagnetic trackers have a longer lag time, but they are not "directional". Also, to get full 6D information from ultrasonics, you need 3 emitters. I am thinking about building my own ultrasonics to be used for head tracking, but it does seem to be a large project. -- /)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/)/) "I speak only for myself" -me ) "But if someone came for you one night _ _ _ _ ___ ) and dragged you away, do you really ( ` D L ( ` /_\ | | ) think your neighbors would even care?" \7 |\ L \7 | | L_ | ) --Jello Biafra, (galt@dsd.es.com) ) _Last Scream of the Missing Neighbors_