title_body: Is it possible to use the head tracking in a FPV goggle with a computer?
upvoted_answer: I have an off the shelf PPM to USB adapter. It isn't this one specifically, but works on the same principle:
  RC USB-Interface III
  
  You can either wire it directly to an R/C Receiver or to a buddy box barrel connector.
  My Fatshark googles have a buddy box output for the head tracking output, which is what I'd typically run into my R/C transmitter. But it should work equally well directly into this.
  The difficult part would be remapping the channels. If I remember correctly the buddy box connection gets roll, pitch, and yaw from channels 5, 6, and 7. And the USB device remaps the inputs to appear as a joystick controller with multiple axis and buttons/sliders.