Hardware & Technical EDTracker disturbed by headset

ZeouLs

Z
I got my hands on two DIY ED Tracker kits and I have an issue with the edtracker combined with my headset. I'm using a Logitech G633 which has a metal band inside. The metal band is disturbing the magnetometer and when I look up/down (it also does a yaw movement). To confirm that it's the metal band, I used some cheapo plastic sony headset and it doesnt have the yaw issue.

Now I'm wondering if anybody has either:
  • a solution to "fixing" my headset
  • a good headset without a metal band around 100 bucks (the cheaper, the better. I'll use them only when I need the headtracker)
looking forward to some answers, thanks in advance
 

AkenBosch

AkenBosch
Obvious question first: have you already tried running again the magnetometer calibration from the EDTracker interface? Technically it should be done whenever there are major "magnetic" changes in the close environment where the tracker gets to be used. Switching from a plastic band to a metal one is definitely a major change.

If it can be of any consolation, I'm having similar issues having switched from a simple plastic headband to using a pair of headphones. The headphones have a plastic arc and a leather head strap so they definitely aren't the cause, the tracker is probably having issues with the magnets in the drivers themselves. Tried to re-calibrate but for some reason the progress bar doesn't look to progress at all when doing that with the tracker strapped to the headphones. All good if I do that away from them though. Magnetic shenanigans.
 

ZeouLs

Z
Cant really recall, have been searching and trying the last couple of days but iirc I only calibrated it on flat surface and then put it on the headset. I'm gonna try to recalibrate it while it's on the headset with metal band.
 

AkenBosch

AkenBosch
The calibration on flat surface should be the "gyro bias" one (or "Set level" as it is called in my version of the GUI), it helps mitigating or eliminating drift, but does nothing for magnetic interference. What you should be looking for is the proper magnetometer calibration, go take a look at page 8 of their PDF brief manual.

http://www.edtracker.co.uk/downloads/EDTracker_Pro_User_Guide.pdf

Also, this bit from page 11 may be relevant to your issue:

"Magnetometer calibration shows distorted green dots

Try to establish what is causing the interference, and remove it from the environment. Normally magnetic fields must be very close to device to cause a problem (<5cm). In some rare cases, the headband of your headset may be magnetic."
 
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AkenBosch

AkenBosch
Chris Simon said:
If everything fails - baseball cap. You can mout the tracker further away from the head band.
Click to expand...

Something I should consider doing, since that actually really sucks:
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ZeouLs said:
done that, still has the yaw, green dots aren't disorted.
Click to expand...

Then maybe finding a way to keep the tracker away from that metal band is really the only solution.
 

dm06

dm06
Well, I'm not an electronic engineer. But I have following thoughts:
1. For me the yaw movements happen at extremely high pitch points. I.e. I need to look mostly at ceiling to make it happen.
2. Something makes me think that this is not magnetometer's issue but gyroscope's one. Because the magnet fields are constant (especially from headphones) so their influence expected to be constant but we have them at certain points.
 

ZeouLs

Z
dm06 said:
Well, I'm not an electronic engineer. But I have following thoughts:
1. For me the yaw movements happen at extremely high pitch points. I.e. I need to look mostly at ceiling to make it happen.
2. Something makes me think that this is not magnetometer's issue but gyroscope's one. Because the magnet fields are constant (especially from headphones) so their influence expected to be constant but we have them at certain points.
Click to expand...
I'll play around and see if its because of a too high/low pitch point
 

ZeouLs

Z
Chris Simon said:
Well, you said that it works fine with plastic headphones in your OP so you're sure it's a magnetic issue. Don't get caught running in circles.
Click to expand...
Since I have 2 tracker, im gonna leave one on the baseball cap (that works since yesterday) and fiddle around with the second one. Maybe it was just a bad magnetometer calibration, too much pitch, or really anything
 

AkenBosch

AkenBosch
dm06 said:
Well, I'm not an electronic engineer. But I have following thoughts:
1. For me the yaw movements happen at extremely high pitch points. I.e. I need to look mostly at ceiling to make it happen.
2. Something makes me think that this is not magnetometer's issue but gyroscope's one. Because the magnet fields are constant (especially from headphones) so their influence expected to be constant but we have them at certain points.
Click to expand...

Logic would make think the same, but actual testing definitely points to magnetometer shenanigans. I just did some additional tinkering trying to make the tracker behave with the headphones.

Tried a calibration at medium sensitivity with the tracker strapped as in the photo above. Took an eternity to complete, the resulting graph gave a generally round green sphere, but with the red one (should be pre-calibration data) totally off and away from it. Tried in game and there was extremely annoying yaw drift at high pitch angles (workaround: if you look up for 5 seconds, remember to look down for another 5 and bam, centering again spot-on XD).

Then I tried a new calibration, with tracker detached from headphones but in the same spot relative to it, by rotating it on its axis. Calibration bar very fast, resulting graph a total mess. Doing the same just 5-6 cm higher, or in front of the headphones gave instead a very round sphere. Those K712 drives must have a hell of a magnet inside.

Then I attached the tracker to headphones again and tried lowering the sensitivity to a minimum; progress bar not even advancing. Scratch that.

Then I said "whatever" and did the opposite, sensitivity to the max. The progress bar completed in a matter of seconds without even moving the headphones! The resulting graph was no graph at all, just a simple green point at the center. I thought "this must be fun in game" and so I tried. Lo and behold, yaw drift at high pitch practically absent. Took off and did a bit of FA Off flying around the station to see if there were any spikes or weird behaviour, and noticed some things:
  • it was fun
  • damn, it was very fun
  • the tracking was just about good, with only a bit of center misalignment once I got back inside, but I also did several exaggerated movements on purpose.

Need additional testing, but the more I do, the less I seem to understand how it all works. :unsure:
 
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