FreeTrack Forum

Hello. I've been watching videos on FreeTrack and noticed that I could use a reflective setup with good success if I do the following:

1. Get a webcam and fiddle with it so it accepts only IR light
2. Get an IR light emitter that I can put on my monitor or something
3. Put some IR tape on my headset to use as tracking points

I have an old MS webcam that might work, but I don't even know the model. It's a round gray camera with an adjustable mount for flat screens with a button on top.

I feel like using reflectors and a USB light emitter would be better than building this somewhat complex setup with LEDs and the like. I've heard of some IR reflective balls I could maybe clip to my headset, but I don't know where to get them.

I've also heard of webcams that have IR LEDs on them, but I don't know which ones would work well for head tracking.

So my questions have to do with all these things -- what do you recommend, where can I find tape for my headset, what webcams are available if mine fails, what sorts of IR light emitters are out there, and what other reflective setups do you think are good?

One thing: I will absolutely not use a hat. I want to either put reflective tape permanently on my headset, or make a clip or clips with no other wires that I can easily attach and detach from my headset. I think the tape reflecting light from a bright IR emitter will make up for the lack of actual LEDs as tracking points.

Thank you, any ideas are helpful.

EDIT: I took a quick look at the point gallery and I found a setup that reflects pretty much exactly what I'd like to have

The IR reflective clip: http://www.free-track.net/images/point_model_gallery/bushlurker_01.jpg

The webcam apparently also emitting IR light: http://www.free-track.net/images/point_model_gallery/deimos_05.jpg
http://www.free-track.net/images/point_model_gallery/deimos_04.jpg

this would be my perfect setup. No batteries or extra wiring required. I just don't know how I could build that headset clip or what webcam that is.

EDIT 2: I was thinking of purchasing a webcam like this: http://www.miniinthebox.com/5-0-megapixel-180-degree-rotating-usb-drive-free-night-vision-webcam-with-buil-in-microphone_p931112.html?currency=USD&litb_from=paid_adwords_shopping&gclid=CLfG-JqL5LwCFW9p7AodK08AjA

I could just open it up and change the LEDs with IR ones, but I don't know if that would be too difficult. Sometimes those LEDs are glued in pretty hard and I don't want to mess with electronics too much.

What sort of reflective material can I use? I don't think I need specifically IR material, but does the tape used by safety workers reflect IR light well?

I'm also thinking of buying a separate IR light emitter, but they have weird power cords and I don't know what kind of plug they use. They don't come with adapters, which is kind of stupid.

I really want the webcam on this page: http://forum.free-track.net/index.php?showtopic=39&page=16

The A4Tech PK-333MB. I can't find it anywhere, but this would solve all my problems in one. Then I'd just need the reflective material and a way to make a simple clip for my headset. If someone could find that webcam, I'll buy it in a heartbeat.

Hi,

I could just open it up and change the LEDs with IR ones, but I don't know if that would be too difficult. Sometimes those LEDs are glued in pretty hard and I don't want to mess with electronics too much.

Then you have to find IR-LEDs with the same forward voltage then the inbuilt, because with the sfh485 you will reach the 500mA of your USB port.

But above all you need a webcam witch is enough sensitive to IR light.
I've tried it with a Logitech 5000 pro without success because of a lack of sensitivity for the reflected IR light. Although I have used this IR-emitter: IR-emitter
Reflective tape or ribbon from safety wests works very well. It needs to be curved to compensate the head movements.

That emitter looks fine, but I don't know how I would connect it or where I'd put it. I don't know what kind of connection that uses. I'd want it on top of my monitor, but there's no way to do that that I can see. I'd also have to find it in the US.

What specific tape would you recommend? I don't know what that stuff is called.

I was thinking of somehow making a clip with balls on it wrapped in that tape. It would be super simple and the webcam + IR emitter would take care of the electronics.

I just had a thought: what about reflective paint? would that reflect IR very well? then I could just dip the balls in that paint and make the clip after it all dries.

probably a coat hanger of some sort, the balls super-glued on, and some sort of plastic clip hold the stuff onto my headset should be fine. I just need the IR emitter, but how do I power it?

can it damage my eyes if I have IR light shining in my face for 3 hours a day?

EDIT: My current testing plan:

- Make the tracking points with the reflective tape wrapped around three wooden balls attached to some kind of wire, maybe a coat hanger. Find a clip to glue or otherwise stick to the points and my headset

- Modify my old Microsoft webcam, take out the IR filter and tape the floppy disk thing to it

- Use an LED flashlight on the reflective tracking points

if that works, I can figure out how to get that IR emitter working and then I'll buy a PSeye camera for better tracking

are there any stores in the US where I can buy reflective tape?

What specific tape would you recommend? I don't know what that stuff is called.

Google is your friend:


http://www.amazon.com/3M-Scotchlite-Reflective-Silver-36-Inch/dp/B000BQRIV2

http://www.ebay.com/bhp/3m-reflective-tape

...

can it damage my eyes if I have IR light shining in my face for 3 hours a day?

The radiation intensity of a typical IR-LED is between 25 à 160 mW/sr. It's not significantly different from normal LEDs. Meanwhile you're eyes do not adapt iris for incoming IR-light because they do not see it.
I would say it's not dangerous when using reasonable and just what need to get a good tracking. MS Kinect is using IR-light and until now nobody is going blind by...

Make sure that you don't have other reflecting objects in front of the cam, mirror, glasses, piercing,... disturbing the tracking by creating extra dots.

I wear glasses, but I've heard of people using the track hat for TrackIR and wearing glasses. Anyway, I think I know how to set this up, but how exactly do you power that IR emitter? I see a strange plug I've never heard of on that thing.

Thanks for the information. I've heard people's eyes can be damaged by IR lasers, so I assumed having IR light going in is like always having a bright white light shining in your face, it might disturb something after a while. I might be able to place it at an angle.

This is the datasheet

http://www.produktinfo.conrad.com/datenblaetter/125000-149999/149241-da-01-en-IR_Cluster_26mm_BL0106_15_28.pdf

6V forward voltage, 60mA current.

i have a 3 led clip working now but i don't like the power cables to my head so i'm thinking of switching a reflective system. i also use the system in a darkened (but not pitch black) room. how does the performace of a well set up reflective system compare to an active system?

also, what makes good reflective spheres for IR. will ball bearings do it?

Hi,

I think ball bearings are not big enough. Give a try with reflective tape.
The most important thing is that your webcam has a good sensitivity for ir-light, so a couple of ir-LEDs will be enough as source.