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DIY TrackIR On the Cheap with OpenTrack

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#1 EmerlistDavjack

  • Posts: 167

Posted 16 September 2018 - 02:10

TrackIR is the ONLY way to play flightsims in my opinion (well, if VR makes you queasy, or you can't spend over $100...), and I think that more people would play our more rigorous sims if TIR was more accessible. Turns out, for $30 you can have a setup that functions as well as the $100+ version.  All it takes is being able to follow a very simple wiring diagram and make some solid connections.  ..and then trying to avoid buying a full simpit worth of controllers and nix your savings because you become addicted to the feel. 


I wrote the basics of this post 3 years ago with a very involved process for setting up the very temperamental Freetrack program.  I chose Freetrack over Opentrack because at that time, Opentrack had a bug that basically broke it.  That bug has been fixed, and Opentrack is better and easier to use than Freetrack.  So I will update this guide for Opentrack, which will coincidentally make it much shorter and easier.  All that sensitivity crap goes away.  Old thread here, for Freetrack Info: https://riseofflight...-cheap-heres-h/


Veterans, take note: Opentrack is far superior to Freetrack.  If you are still using Freetrack, even though it still works for you, you may want to consider OpenTrack. 


Other note:  FaceTrackNoIR exists.  It eats system resources and it does not allow for nearly the same head movement range as an IR LED setup.  Instead of head movements that feel natural, the best way to use that is as a "gesture" program, where smaller looks go a longer way.  I found it fine for looking around a cockpit, terrible for checking my six. 


OPENTRACK: https://sourceforge....entrack.mirror/


Standard Hat Build:


1) Go here and learn about making the IR hat:  http://www.free-trac...?showtopic=1856

      -If you wont be soldering, I highly recommend "Wire Glue" or in the USA "Liquid Electrical Tape"  over tape; it's a better connection.  Be sure to twist exposed wired tightly around the LED lead a few times. If soldering, remember what my daddy told me, "The trick to proper soldering is to curse at the thing while you do it."   There are also Crimp Connectors that work great, and I use them on my motorcycle, but I just didn't have any on hand when I made my hat, so I soldered/taped. 

      -SFH485P 1.5v 880nm LEDs are easy and cheap. 

          From China: https://www.ebay.com...wkAAOSwf-VWWCq9

      -22ohm resistors will give you brighter bulbs than the 30ohm listed on the build guide above (best viewing angle, slightly less battery life): http://www.ebay.com/itm/250867360251

      -Battery Case (can be found cheaper): http://www.ebay.com/itm/130625020017

      -I scavenged PSU wire from an old computer case.  Light gauge speaker wire would also work.


NOTE:  The "wider" you make your hat, the less jittery/twitchy it will be.  If you make it too wide, then the "rear" or "far" lateral LED dims significantly when you look off to the side of the camera.    I have attached a photo of my hat below, bask in the glory of the Gorilla Tapeā„¢, binder clips, and cat fur.  Figuring out how to build the hat itself is your own fun challenge.


SECOND NOTE: It is completely acceptable to skimp on the resistors and go with 1 AA battery in a single holder and a parallel circuit for the LEDs.  Voltage drop is 1.5V across the board and while online electrical goons will tell you "you are damaging your LEDs" or something, they will not catch fire (lol) and they are 10 for $1.  So.  Make your own mind on that one.  My hat is 1 AA/resistorless: battery probably doesn't last as long, but it lasts a long time.  The LED have lasted me 3 years with no problems.  No worries about battery power on a two-hour multiplayer scenario.  I decided that resistors weren't worth it, since it just makes more connections that could break in the future.




My thanks to =CFC=FatherTed for recommending the PS3Eye webcam years ago.


PS3Eye:  These things are cheap on ebay.  $3-10 shipped (so cheap they give two away now).  The trick is that since these are made to use with an IR wand, their IR filters are REALLY weak.  You do not need to take the PS3Eye apart or modify it in any way.



-Download and install CodeLaboratories PS3Eye Windows Drivers: https://codelaboratories.com/downloads


IR FILTER:  Stop messing around with overexposed films and floppy disks and buy an IR Pass filter.  BUY AN IR PASS FILTER.  You'll need one at 850nm to let the SFH485p's 860nm to pass.  See the attached picture below for my highly engineered camera/filter rig. These things are so good, the sun looks like a pale red spot on black.  They block all visible light, and then the PS3Eye auto-exposure attempts to compensate, but since the IR LEDs pass the filter, those seem to be what it uses to auto expose.  And the result is constant dot perfection.   http://www.ebay.com/itm/381324614246


Opentrack Settings:  Copy the first two pictures below, change only if you want to learn how (or send me a PM if for some reason these settings don't seem to work for you). Input: PointTracker 1.1.  Output: Freetrack 2.0 Enhanced.  Filter: Accela.  The little hammers next to them access the settings.  Start by copying my settings from the attached pictures below. 


Model Dimensions:  Under the Model tab of the Input (Pointtracker 1.1) settings, fill in the dimensions of your cap, the page shows you how to measure.  


Model Position: This is very, VERY important, you must read this carefully.  The values correspond to the position where your head rotates relative to the model.   This is the center of your head, that empty space between your ears.   Look at the picture below with the IR points shown, notice the little Yellow Crosshair.  That where the program thinks the rotation point of your head is.  The Model Position values are how it computes that spot on the fly as it tracks.  There are three ways to fix model position.


1) Use the calibrate option.  Look at the IR points in the tracking screen with tracking on, and make sure that they look symmetrical and pointing straight at the camera.  My camera is mounted about a foot above me on a big ole TV, so what I do is angle my cap up slightly (and the camera down) so that the points are directly at the camera.  This makes it work just that much better.  Hit Start Calibration while looking straight at the camera. Do not roll your head or move your head position forward, backward, or side to side.  Remember your view has to start centered at the camera.  Look up smoothly, then down smoothly, do it again.  Do it again.  Do it again.  Center head.  Now Yaw head to the left, then smoothly over to the right, then back, and do that a few times.  Then look straight ahead and hit stop calibration.  The program is taking readings and making averages the more you do it, so when I tried it, I did it 4 times each, but if you do more, it could make it better. The program will tell you how many "samples" you've captured.  Remember that each Pitch or Yaw of your head should be as much the same as possible.


That option works, and will probably get you in the air, but it did not fully do it for me.  I had one Calibrate that did really well, but most of them were off significantly.  It could be a could jumping off point to refine with option 3, below. 


2) Measure.  This one is so much easier with a friend, or wife, or sufficiently intelligent cat.  It is also going to get you a nearly exact value.  Look at the picture below where I am looking to the side in the Tracking screen.  You can imagine how the hat is sitting on my head, and the crosshair sorta looks like it would be in the middle, huh? The Yellow Crosshair should remain relatively centered in the sceen when I yaw my head to the side. That's what we are going for. 


Values are as usual: 

X is side-to-side,  Positive values, Right.  Negative values, Left.

Y is Up and Down, Positive values, Up. Negative values, Below.

Z is Forward and Back,  Positive values, Back. Negative values, Forward.


The reference point is the Top, Center LED, and you measure TO the center of the head.  Look at my values:  X = 10mm, Y = -141, and Z = 125.  That X value means that I didn't center the LED on my hat, so I used that to compensate.  Start with that value at zero and do it last.  The Y value means that my head rotation point is 141mm below (negative) the top LED on my hat.  The Z value means that the head rotation point is 125mm behind the Top LED.  Since I used an American Style Ballcap, I just measured off the button on top, roughly the center.  Have your helper measure Y and Z and put those values into the program.  See where the Yellow Crosshair is when you have everything centered, then adjust the X value until it is centered.  If you make your model perfectly and attach it perfectly, that should be 0. 


3) Screw measuring, just adjust the Yellow Crosshair until it is centered.  The great thing about OpenTrack is that all this stuff can be adjusted while tracking is active.  So guess as close as you can and then slide the Yellow Crosshair around by clicking the arrows at the model position values. 


Once again, Model Position is extremely important and getting it right will ensure a really nice translation and not something that is just close enough. 




Summary of Axes:


Yaw:  Turning your head from side to side laterally.

Pitch: Pivoting head up and down.

Roll: Pivoting head radially.  This axis is not very necessary, indeed sometimes annoying, for aviation head tracking. I leave mine as a straight curve, because it feels "real" but I could also see limiting it to very little response because it isn't actually needed for aviation.


X: Moving head/body laterally

Y: Moving head/body up or down  Useful for seeing over high back-rests, such as on the Hanriot or Felixstowe. 

Z: Moving head/body forward/backward.  This can be used for in-game Zoom as well as minor body movements in cockpit.



Freetrack turned out to be a MESS in comparison, Opentrack is very easy.  There is no need or reason for you to copy my exact curves, you should absolutely set up the curves yourself to suit your position and monitor size.  Look down at the Yaw curve photo below.  Do you see the red dot on the red line?  This is what the curves look like with tracking active.  That red dot is where the program thinks I am looking, the X values are degrees of my head yaw, and the Y values are the degrees translated to the in-game view.  You can see that I have it topping out around 40degrees for my head, and 160 degrees for the game. 


40 degrees is me looking at the edge of my monitor.  150 degrees puts the center of my view 30 degrees off the tail of the plane (180 being straight back, right), but since the field of view is wide, that results in still being able to see past the other side of the tail, as if out of the side of my vision, but not looking straight 180 degrees back like an owl.  I try to make it feel like looking at a monitor, but in game it looks like life.  With my settings I can literally shift my body over and peer down over the side of my cockpit.  It's sweet.  


Note: More translation is not always better.  The farther you go, the more disorienting it can be.  For instance, the human head/neck/back can easily look up above you more than 180degrees, but I found that in game, and with how Opentrack works, you really don't want or need to do that.  It's good enough to top it out at 160, IMO, and then when you are looking around while rolling/looping in a dogfight you don't end up turning your head to far left or right while looking up at +200degrees and having the camera pivot wildly.  At 160, you can still look straight up.  On my settings, you can see that I have chosen ~30 degrees (looking at the top edge of my TV) and, unlike Yaw, limited Pitch directly at 160 because I never want it to go further under any circumstances.   Similarly, if your Body Position values are too strong, any little shifts you make in your seat will translate to the cockpit.  I have mine set on relatively shallow curves, so I really have to move my body to see it happen.  You can set an exponential curve for Z so that a little bit forward and back does nothing, but if you move your head deliberately 8 inches forward, pilot moves/view zooms in. 


Important commands:


In Opentrack, under Options > Shortcuts, you see the hotkeys.  There are only two essential hotkeys I ever use, but you might find others useful.  "Center" takes wherever your head is looking at the moment and calls that the new center view for tracking.  So, for instance, if I hit Center while looking 90 degrees right, then look back at the screen, my view will be looking 90 degrees left.  I use Center all the time, because it is really hard to keep your body/head in exactly the same place.  So after kicking my rudder around and moving around in a dogfight, I'll look straight back at the camera and hit Center to make sure that it all feels right.  I like to aim down the sights using TIR and no "view locking" or whatever (it makes it more challenging), and the Center command makes sure that my body and the camera are in tune.


The other essential key is Toggle Tracking.  This is like hitting the Start or Stop button in the program, and hitting it will cause the screen to center in the game when the tracking turns off.  Hitting it again will reboot the tracking.  The program is not perfect, and will sometimes confuse the orientation of your hat (moving the Yellow Crosshair somewhere wacky), and you will find yourself looking somewhere strange in game.  Happens often in the heat of the moment if you move your head too far, or if, for instance, a family member distracts you and you look completely away from the screen.  Center will not work in this instance, but a quick double tap of Toggle Tracking while looking straight ahead will fix it. 


KNOW YOUR SAVE SNAP VIEW COMMAND:  Interestingly enough, I was just in a Black September mission with a squadron mate whose TIR went completely batshit...but only in the D7F.  Turns out that he was using a third-party recording program hotkey of ALT-F10.  He hit that hotkey while looking off-axis, and the F10 press triggered RoF to re-set what it considered his center snap view.  It seemed like TIR was broken...but it wasn't, it was the F10 press.  With this in mind, don't choose Opentrack hotkeys that conflict in any way with any other key.  I use Center as Ctrl-Shift-Z, and Toggle Tracking as Ctrl-K.  Both Z and K aren't bound to anything in game. 


In RoF/BoX the default key to set what ROF considers "center view" is F10.  For EACH AIRCRAFT you will have to make sure that the RoF/BoX center (F10) is what you want to consider as OpenTrack's Center.  So whenever you hit Opentracks Center hotkey it will return you to the proper ROF center every time.  I have my ROF centers all set to fully zoomed out, pilot seated fully back, view centered on Iron Sights or Aldis (if possible, I don't set my center to Off-axis to match the Collimator in Albs or D7s).  I seat the pilot fully back so that I can lean back in my chair and then have any lean forward translate on the Z axis of Freetrack and shift my pilot forward in game.  You will notice that if you install the Aldis/Gunsights, your standard Centered View is not looking straight down them.  What to do is to get in the plane, maneuver your head to where you want the game to think is center (for instance, a perfectly lined up Aldis picture), and hit F10.  You can do this with tracking off and using the "Pilot Head" commands in the game, which by default are the Home cluster.  Remember each aircraft saves this separately.


Final note on monitor:  This setup will work for anybody, but if you have a 20" monitor, you cannot turn your head too much and so it feels more like a "gesture" than like looking around.  I use a 47" Samsung 1080P 60hz LCD TV as my monitor, and while the pixel density is a little bit low, it works really great for track IR.  I have a 40 degree head travel to each side and I am looking at the edge of the monitor.  So while 60hz TVs have a downside in that they cannot run higher FPS, they work very well for flight sims, especially for encompassing your forward field of view and allowing you to turn your head more than otherwise, and therefore have better accuracy. 


Another factor is that a 4k monitor might not actually help you see better in a flight sim.  Our very own Phil put up a video for DCS showing that you see aircraft from twice as far with 1080p as with 1440p.  Does that happen in RoF/BoX?  I have no idea, but the basic principle tells me that it might. 


So, to recap. 


1) Get Opentrack, get PS3Eye, 1 860nm IR pass filter, 3 SFH485P 850nm IR LEDs, a single battery case.  Build a single-battery hat with no resistors for easiest build.

2) Set your Model Dimensions

3) Calibrate, Measure, or Guess-and-adjust your Model Position Values to put that little Yellow Crosshair where the rotation point of your head is. 

4) With tracking on, adjust your curves so that looking at the edge of your monitor looks as far as you want it to in game.  160 degrees is a great value for looking back or up like a human.

5) Familiarize yourself with Hotkeys and how to Center, Re-center, and Fix a momentary lapse in TIR judgement.  I don't know if the retail versions ever screw up what they think the hat is (where are so many clever ways an engineer could prevent that), but Opentrack will occasionally screw up and you have to reboot it with Toggle Tracking, but that only takes a half a second.   

6) And finally, be proud of yourself for building a quality device on the cheap and enjoy some of the most heart-pounding and immersive gaming you will ever have! 


I hope this is helpful and allows more people to get into the world of immersive, realistic flight sims!


Note:  Yeah, it would have been nice to embed the photos in the writing, but I want them to stay up as long as this forum does, not eventually be erased by some free hosting site. 

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#2 EmerlistDavjack

  • Posts: 167

Posted 16 September 2018 - 02:11

Awwww CRAP.  I genuinely thought I was writing this in the "How To's, Instructions, and SDK" forum.  Can a moderator move it, please? 

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#3 US103_Baer

  • Posts: 481

Posted 16 September 2018 - 03:09

Superb write up.

Does Opentrack support Wiimote yet? I'd swap out from FT in a heartbeat if it did
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#4 Panthercules

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Posted 16 September 2018 - 04:13

Awwww CRAP.  I genuinely thought I was writing this in the "How To's, Instructions, and SDK" forum.  Can a moderator move it, please? 



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#5 EmerlistDavjack

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Posted 16 September 2018 - 04:17

Superb write up.

Does Opentrack support Wiimote yet? I'd swap out from FT in a heartbeat if it did



I have never tried WiiMote or any single-point tracking solutions.  Ask Plank, he mentioned it in my last thread for Freetrack.


Thanks Panthercules!

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