Build a 2 DOF Wireless Head Tracker – Cheap!

Not long ago I needed a whole bunch of head trackers for just one week. Not wanting to invest tens of thousands of dollars in high-end tracking systems, I came up with an easy DIY head tracking system constructed from the guts of a Gyration Air Mouse. The Air Mouse contains a 2 degree of freedom (2 DOF – Yaw and Elevation) orientation sensor. In my application, users didn’t really roll their head (i.e. tilt their head from side to side), so 2 DOF actually worked pretty well. The tracker is really responsive with very little lag. I used Gyration’s Go Pro Air Mouse, but I suspect any of their Air Mouse family can be made to work. This article presents the hardware modification in detail and source code to integrate the tracker into your own software.

A quick disclaimer… The resulting head tracker will exhibit some drift over time. Its not perfect. However for short gaming sessions or experimental use, it is great. Also there are some good methods, explained at the end of this article, to minimize the drift.

Head Tracker in Action on a V6 HMD

Step 1 – Tear out the guts of the mouse.

Step 2 – Extract the Circuit Boards

Step 3 – Remove the unnecessary junk from the circuit boards

Step 4 – Remove more junk…

Step 5 – Remove the power connectors and bypass Air-mode switch

Step 6 – Trim some extra circuit board away to make it smaller.

Step 7 – Setup the new power source.

Step 8 – Reassemble the boards.

Step 9 – Hooking up the head tracker

Step 10 – Packaging

Step 11 – The Software

Step 12 – How to minimize tracker drift