An orientation sensor includes variable resistance elements within the
sensor, the variable resistance elements forming an electric circuit with
a conductive ball or drop of conductive material. The resistance of the
electric circuit uniquely identifies the orientation of the apparatus. A
method of determining the orientation of an apparatus includes measuring
the resistance of a circuit completed between two conductive members in
the apparatus, and determining the position of a freely movable conductive
member in the apparatus from the measured resistance.