Alternative Text Description of Figure 2: Modified Tactile Mouse
The figure shows how the rotational angle of a tactile mouse can be taken into account with its relation to a computer screen. When the mouse is rotated by an angle 
θ about the optical sensor point as shown in (b), the pin position changes to (X3 ,Y3 ). This angular displacement θ is measured by the angle sensor and the new pin position (X3 ,Y3 ) can then be determined by Equation 1. The information on the screen corresponding to the new pin position is then displayed on the tactile.