A memory apparatus comprises a media, a tip adapted to write information
to and read information from said media, a media movement mechanism
attached to said media and configured to move said media in response to
media control signals, and a capacitive sensor configured to detect an
amount of relative movement of said media and said tip in at least an
x-axis direction. The capacitive sensor includes a fixed comb having
fingers protruding in an x-axis direction, a moving comb connected having
fingers protruding in an x-axis direction, and an electrical path
connected to said fixed comb and an electrical path connected to said
moving comb. The relative movement in at least the x-axis direction is
determined at least in part on a change in capacitance between said fixed
and moving combs of said capacitive sensor.