Utilization of gyros used for measuring acceleration in cellphones, and in contrast to using some sort of a sensor mounted in front of the user's head, most often a web- cam which is the mainstream method in head- tracking, represents the principle on which the EDTracker head- tracking device works. While the dimensions of this device are smaller than the dimensions of most separate components of other head- tracking systems, it only allows for head tracking with three degrees of freedom, which is to say rotation around three axes. Software which allows for calibrating the device and which also provides joystick emulation is provided, while the OpenTrack software facilitates the usage of different head- tracking protocols including emulation of the TrackIR system with three degrees of freedom: