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Bright Room? Want track Ir? Read on....


Friar

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  • 1. DDz Quorum

Following on from a comment that jediteo made the other night about how to modify Track Ir to work in a bright room I conducted a little experiment.

jedi suggested that if you are in a room where the light sends the trackir camera crazy and just will not work then the light can be filtered out by placing the insides of a floppy disk over the camera.

Experiment.

1. remove the floppy disk from inside of a floppy disk.. :-\

2. start up your track ir on a bright sunny day.

3. click view and tracking from within the track ir software.

you track ir screen will probably be awash with red and green reflected light.

4. Hold the floppy disk over the camera.

the reflected light disappears.

now the only way i could test the next bit was as follows...

Whilst holding the floppy disk in front of the camera, i pointed my tv remove control at the camera pressed a channel number.

this brought up a green dot on the track ir screen.

this confirms what jediteo said, the disk blocks out normal light but lets through infra red light.

So to conclude, although this mod will not work for the normal reflected spots system, if you have the clip or can wire together 3 ir l.e.ds it should, theoretically work the track ir system.

if any one would like to take this further, please post.

......so the cat is put in a sealed box..........

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My Freetrack setup works in brightsunshine in a rather large rooms (my family bought an old schoolhouse, my room is an old classroom). I used to have problems with light interference with my old setup, but since I swithched the lightsource from green to IR leds my problems was solved, and I can play anytime of day whatever the ambient lighting. The track ir emits an IR lightbeam, which is reflected onto the camera, some freetrack users use the same setup, but with a webcam with IR leds attached to it and reflective dots.

The problem is that a camera cannot distinguish between the reflected light and ambient Infrarred light. This is where the magnetic disc (the storage part) of a floppy disc (3.4 inch I believe, I've got about 200 ones I do not/ cannot use)

The goal is to prevent ambient IR light to interfere with the reflected IR light. The magnetic disc of a floppy disc attached infront of the lens of motion capture device (the track IR unit) will negate visable, and to a great extent ambient IR light.

To salvage the magnetic disc is rather easy.

1. find a suitable floppy disc to be sacrificed (sounded a bit more ritualistic in my head...)

2. Pry off the metal sliding cover at the bottom of the disc. The black thing inside is the disc you want (the 1.44meg storage area)

3. pry off the plastic sides that contain the inside disc (the outer square cover). There might also be a loose small spring, that forces back the metal cover when the computer is not reading the disc (very painful to walk on with bare feet)

4. use a pair of scissors to cut out an appropriate size to cover the lens.

5. attach with tape to hold it to the camera (track IR device). Be sure to not to cover the lens with tape as that will destort the picture (a few pieces around the edges should be enough)

6. Test the tracking capability in the software, you may have to change your threshold for how much light is detected by the device.

Additional layers may be needed if you have large amounts of ambient light.

As the reflected IR light will be stronger than the ambient light, the reflected light will pass through the improvised filter(floppy disc centre) but the ambient will not, hence making the device fully functional, regardless of ambient lighting.

I hope this proves to be useful. I do apologise for any lack of clarity in the above post, I am writing this while I am quite tired and have a pretty severe headache. I wish you the best of luck and if you need any help, you know where to find me (on BGs six waiting for twenty seconds, wait a minute I should not have written that)

Ps I do realise I use a lot a parentheses (almost as many as C.S Lewis)

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On a side note I discovered that naturalpoint sells a headset clip with active IR leds (same setup as I built myself for a grand total of 5£)

This might help if the reflected light is not stong enough. My cheap IR leds x3 powered by a 1.2 volt AA battery easily penetrates two layers of floppy disc.

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My Freetrack setup works in brightsunshine in a rather large rooms (my family bought an old schoolhouse, my room is an old classroom). I used to have problems with light interference with my old setup, but since I swithched the lightsource from green to IR leds my problems was solved, and I can play anytime of day whatever the ambient lighting. The track ir emits an IR lightbeam, which is reflected onto the camera, some freetrack users use the same setup, but with a webcam with IR leds attached to it and reflective dots.

The problem is that a camera cannot distinguish between the reflected light and ambient Infrarred light. This is where the magnetic disc (the storage part) of a floppy disc (3.4 inch I believe, I've got about 200 ones I do not/ cannot use)

The goal is to prevent ambient IR light to interfere with the reflected IR light. The magnetic disc of a floppy disc attached infront of the lens of motion capture device (the track IR unit) will negate visable, and to a great extent ambient IR light.

To salvage the magnetic disc is rather easy.

1. find a suitable floppy disc to be sacrificed (sounded a bit more ritualistic in my head...)

2. Pry off the metal sliding cover at the bottom of the disc. The black thing inside is the disc you want (the 1.44meg storage area)

3. pry off the plastic sides that contain the inside disc (the outer square cover). There might also be a loose small spring, that forces back the metal cover when the computer is not reading the disc (very painful to walk on with bare feet)

4. use a pair of scissors to cut out an appropriate size to cover the lens.

5. attach with tape to hold it to the camera (track IR device). Be sure to not to cover the lens with tape as that will destort the picture (a few pieces around the edges should be enough)

6. Test the tracking capability in the software, you may have to change your threshold for how much light is detected by the device.

Additional layers may be needed if you have large amounts of ambient light.

As the reflected IR light will be stronger than the ambient light, the reflected light will pass through the improvised filter(floppy disc centre) but the ambient will not, hence making the device fully functional, regardless of ambient lighting.

I hope this proves to be useful. I do apologise for any lack of clarity in the above post, I am writing this while I am quite tired and have a pretty severe headache. I wish you the best of luck and if you need any help, you know where to find me (on BGs six waiting for twenty seconds, wait a minute I should not have written that)

Ps I do realise I use a lot a parentheses (almost as many as C.S Lewis)

Thanks Jedi. I'll give that a try in the morning when I will also have a severe headache.

:bg:

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