摘要 |
One or more fixed sensing electrodes are employed to sense movement of a mass both within the plane of the mass/electrodes and along an axis normal to that plane. In order to measure movement of the mass along the axis normal to the plane, a reference capacitance is measured between the fixed sensing electrode(s) and an underlying conducting plane and a measurement capacitance is measured between the mass and the underlying conducting plane. A value Cv-KCf may be computed, where Cf is the reference capacitance, Cv is the measurement capacitance, and K is a predetermined constant. In accordance with certain embodiments of the invention, a standard one or two axis acceleration sensor that measures movement of the mass within the plane can be used to also measure movement of the mass in the axis normal to the plane.
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