From: owner-3dui@hitl.washington.edu on behalf of Doug Bowman
[bowman@vt.edu]
Sent: Thursday, October 11, 2001 2:27 PM
To: Anders Backman; 3d-ui@hitl.washington.edu
Subject: RE: VR8 + Ascention = problems

Anders, I don't have this exact setup, but I do have a Virtual
Research V8. The fan on my system is in the control box, not on
the HMD itself. Since the display (and therefore the head tracker)
are not near the control box (the cable is quite long) there
should be no interference from this. Why is your tracker so close
to the fan?

--
Doug A. Bowman, Ph.D. (540) 231-2058
Assistant Professor   (540) 231-6075 (fax)
Computer Science      bowman@vt.edu
Virginia Tech       www.cs.vt.edu/~bowman/




> -----Original Message-----
> From: owner-3dui@hitl.washington.edu
> [mailto:owner-3dui@hitl.washington.edu]On Behalf Of Anders Backman
> Sent: Thursday, October 11, 2001 2:12 PM
> To: 3d-ui@hitl.washington.edu
> Subject: VR8 + Ascention = problems
> 
> 
> 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
> 
>