From: owner-3dui@hitl.washington.edu on behalf of Drew Kessler [dkessler@eecs.lehigh.edu] Sent: Thursday, October 11, 2001 4:33 PM To: 3d-ui@hitl.washington.edu Subject: Re: VR8 + Ascention = problems Anders, I have used a Motionstar system with a Virtual Research V8 in the past (I am not using a Motionstar system now). I do not remember a specific problem with the fan on the V8 display (take another look, Doug :) Unless your V8 is "special", it has a fan just above the midpoint between the LCD displays). However, I did have problems with significant drift in the sensor values (that reminded me of being on a small boat in a big ocean). We addressed this problem by using the built-in filters of the system. The system was set up with the "SUDDENOUTPUTCHANGE", "DCFILTER" and "ACWIDENOTCHFILTER" set (values of 0x20, 0x01, and 0x02 or'd together for the "setup" field, from the source code I have). I assume that the kind people at Ascention would have already suggested this, though... -Drew On Thursday, October 11, 2001, Anders Backman wrote: > Hi all. > > Im wondering if anyone else have have experienced the following problems: > > We have a Virtual Research VR8 (probably the most common HMD) and a Ascention Motionstar (equal to FlockOfBirds, except for a Ethernet interface). > > We are experiencing interference problem from the HMD:s fan. > When the sensor is held close (or at the sensor mounting point at the HMD) to the fan, the sensor returns really noisy data. The orientation and position swings like being ombord a ship in a really severe storm! > > Moving the sensor just a feet or so from the fan, reduces/removes the problem. > Also shutting down the HMD (fan) works. SO I guess we can really blame the fan in the HMD. > > The problem is slightly less when the sensor is really close to the transmitter. > As the sensor magnetic field is stronger than the interfearence field from the fan. > > We have approached both Virtual Research as well as Ascention regarding this, but there seems to be no solution. We have changed the fan in the HMD, but nothing helps. > > So is there anyone out there that have experienced the same problems, and is there a solution? > > I guess that shutting the fan down is a potentially really bad solution! > ________________________________________________________________ > Anders Backman Email: andersb@cs.umu.se > HPC2N/VRlab Phone: +46 (0)90-786 9936 > Umea university Cellular: +46 (0)70-392 64 67 > S-901 87 UMEA SWEDEN Fax: +46 90-786 6126 > http://www.cs.umu.se/~andersb > > > -- ___________________________________________________________________________ G. Drew Kessler, Ph.D., Assistant Professor dkessler@cse.lehigh.edu Computer Science and Engineering Department Office: 118A Packard Lab 19 Memorial Drive West Phone: (610)758-4818 Lehigh University Fax: (610)758-4096 Bethlehem, PA, USA 18015 http://www.cse.lehigh.edu/~dkessler/