A position sensing device having an insulating board, a first conductive
sensing element, a second conductive sensing element, an oscillator,
conductive material, a differential amplifier, and a processor. The first
and second spaced conductive sensing elements are on the insulating
board. The oscillator generates an oscillating signals and the conductive
material is spaced from the sensing elements. The conductive material
receives the oscillating signal to create an electric field between the
conductive material and the first and second sensing elements. The
differential amplifier includes differential inputs that are connected to
the conductive sensing elements. The signal levels at the differential
inputs vary based on the position of a pointing object of a user relative
to the first and second conductive sensing elements. The processor
generates a position signal based on an output of the differential
amplifier.