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http://www.free-track.net
In case people are interested, this is how head trackers work: there has to be a bright point of light that a camera can pickup, and seperate from the background. This is done with either infrared LEDs mounted on a headset or hat, or with reflectors that reflect infrared light from a different source. Head tracking software is able to translate this into head movements depending on the number of points. With one point, it translates it into 2 degrees of freedom (DOF), which is pitch and yaw. This allows you to look around but not move or roll. With 3 points, it's able to track 6DOF, which is pitch, yaw, left and right movements, up and down movements, forward and backward movements, and roll.
This is a good example of a 4-point cap, which isn't needed. A 3 point cap is pretty much the same, except without the bottom-middle point. We'll be making a 3 point clip which is 3 points aligned up the side of a headset. This video shows how you can see the guy's movements with just 4 points of light.
For this tutorial, you'll need to get yourself a nighvision webcam. I found a great one at newegg, the KINAMAX WCM-6LNV. It's $15, and comes with 6 infrared LEDs that turn on in low light. Having these LEDs will save us time and money, because otherwise we'd need to make a cap with 3 LEDs on it, which requires tools that many don't have, and you'd always be replacing batteries. You can get the camera here:
http://www.newegg.co...N82E16830200001
Next, you'll need a headset. Any headset will probably work, you'll just need to modify how you attach your clip and reflectors to it. You'll also need some reflective tape. Go to the automotive section at walmart, and you should find some. The white tape works best, a roll of it is about $10. Lastly, you'll need some cardboard, scotch tape, and a metal coathanger.
Now, lets get started.
Connect your new nightvision webcam and install the drivers. After you confirm it's working, get something that will block light from entering the light censors. These determine whether the IR LEDs are on or not - since you'll probably be flying both in day and night, you don't want the LEDs to shut off when the sun's shining into the room. Some webcams have two light censors, one on the top and one on the front. Block both of those with something very dark, I used electrical tape.
After this, you'll need to make the clip. Take some wire cutters to your metal coathanger. You want the straight portion on the bottom, so cut that away from the rest of the hanger. When that's done, you want to bend it in one position so it looks like this from a side view:
After that's done, you want to take the ends and bend them so they're 90 degrees up/down. It'll be easier to do this with pliers. This will make it easier to mount the reflectors on the ends. It should look like this from the side after you bend the ends:
Now you have to make two cardboard squares to put on the ends of the hanger. These will make it easier to stick the reflectors on there. Get some scissors and cut two squares, each about 1 inch by 1 inch. After this, stick the cardboard on the ends of the hanger. Don't tape them on there yet, you'll have to make some adjustments to their angle when you're fine tuning the tracker.
Next, get your reflective tape. You'll have to cut out three circles, each with a diameter of at least 0.75 inches. You'll want to put them on some cardboard or strong paper to give them rigidness. I just got a good 3 inch strip or so and stuck it on some cardboard, then cut out the 3 circles from that. Make sure the circles are nice and big, otherwise you won't be able to turn your head as much or get too far away from the webcam.
Now you need to tape two of the reflectors to your little cardboard squares. After this, tape your coat hanger to the headset. You'll have to use a good mount of tape to make sure the hanger stays in place and doesn't move around on the headset. You'll also have to position the hanger on the headset to where it will be perfectly vertical, or as close as you can get. It doesn't have to be perfect, so don't beat yourself up if you can't get it...it just has to be close. After this, take your third reflector and tape it onto the headset where you taped the hanger.
Look at how I did it if you need some help, it works great for me:
Construction is now complete
You just have to fine tune the reflectors now. Remember the cardboard squares we left able to pivot around? Well we did this because we need to position them so we get the most use out of the reflectors. The middle reflector will be the target for the top and bottom reflectors, since we can't move it. Get into Free-Track and change the settings so it only sees the three reflectors (I set exposure to the minimum setting and that works fine) Now turn your head to one direction until the tracker no longer sees the middle reflector. Now you need to pivot your top and bottom reflectors until they disappear at that exact same point as well. Now when you turn your head up/down/left/right all the reflectors should disappear at the same point.Now take some tape and tape the cardboard squares to the hanger in a way that will prevent them from turning. It's not the most sturdy, but don't treat it like crap and it should work great. You should be finished now, I'm not going to give you a tutorial on how to use and setup freetrack since there are a ton of resources for that.
Good luck with making it, and ask questions if you can't figure some stuff out. Post if you have some success with this design too
Woo for us cheapskates! I wonder how well it would work if I put a few LEDs on my headset connected to a battery pack lmao.
expensive!
