title_body: Is it possible to use the head tracking in a FPV goggle with a computer? This might not be the best place to ask this question, but it feels like a good place to start.
  There are a few FPV goggles with built in head tracking that sends out a PPM signal. Is there a way to use this together with a computer (for example to emulate a mouse)? As far as I know you would need something to interpret the PPM signal and convert it to a USB signal. One solution / workaround is to connect the goggles to a transmitter and then connect the transmitter to the computer. This, however, feels like a clunky solution and it would be nice with something smaller.
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.