I used to have a nokia N8, and sometimes I used it as a motion detector using the camera as webcam + FaceTrackNoIr
It obviously wasn't as good as trackir, but with 1280x720@30fps I could have lots of fun, maybe not be competitive, but for fun it was good...
Now I have a android phone, and after 2 hours searching, I haven't found any app to use the camera as 720p@30fps webcam, to be honest I thought I would find a app for 1080p@30fps webcam in less then 10 minutes, but I was wrong...
So I was thinking by myself, the oculus rift don't use camera or infra red to detect motion, it uses accelerometers and possibily gyroscope (correct if i'm wrong)
And the phone also has accelerometers and gyroscope...
So I was thinking, is there any app for android that reads the sensors and send to the computer, so we can use it on games?