There is another way to do this without strapping a phone to your head, but you'll need a webcam. Or you can use your phone, but you'll need to find an appropriate position for it directly in front of you.
I'm using head tracking in LFS for almost a year now, using Opentrack and AITrack in tandem, as well as Iriun Webcam to send my phone camera output to pc, acting like a webcam. If you're interested I can share the whole process, it gives almost the same result as with this method, without some of the cons.