Joel Clemens writes on his blog. "Using the playstation 3 sixaxis controller, along with a free program called GlovePIE, I am building a cheap, accessible VR system. The helmet shown is a retrofitted HMD (head mounted display), HMDs are much cheaper than VR helmets because they don't have head tracking. (which can now be substituted with a PS3 controller for a mere 40$ instead of hundreds. [recently it has come to my attention that there is such thing as a gyro mouse, which can be used for head tracking. I was somewhat relieved to see that the ps3 controller is still cheaper than the mouse in question]"