Various systems and methods are employed for lift-detection. Beam
triangulation can be used, and in one embodiment, an optical lift detection module is separate from the
optical tracking module. In one embodiment, a capacitive lift detection technique is used. A
capacitor is built into the bottom case of the mouse. When the mouse is resting on a surface, the surface material serves as a
dielectric for the
capacitor, while air serves as the
dielectric when the mouse is lifted. This
dielectric change leads to a change in the
capacitance value, leading to detection of lift. In one embodiment, a
capacitor with an easily compressable material inserted between the two electrodes is used. In another embodiment, a mechanical
plunger with an
elastic membrane is used for lift detection. Lift detection can be tunable and / or customizable. The actual height of the life can be detected, rather than simple on-off notifications.