Switched capacitance automatic meter reading device
AssigneeSiecor Corporation
InventorJohn E. Veneruso
Life of this patent
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Abstract
A humidity and temperature resistant apparatus for determining the orientation of a rotatable meter hand relative to a dial spaced apart from a meter hand that creates and depletes a charge between a center electrode, a meter hand, and an outer electrode ( a pad) very rapidly to transport electrons through a resistor capacitor combination, attached to a positive power supply, whereby the average current drawn through the resistor capacitor combination creates a voltage across the resistor capacitor combination that corresponds proportionally to the magnitude of the capacitance being measured.
Claims12
An apparatus for remotely monitoring the position of a meter hand affixed to an axle, as the meter hand is rotated by the axle comprising:
- (a) an array of spaced apart electrodes disposed on a surface of a substrate delimiting a center portion, an aperture in said substrate located in said center portion for receiving said axle, a center electrode disposed on said surface circumscribing said aperture and spaced apart from said array of spaced apart electrodes, said meter hand being spaced apart from said array of spaced apart electrodes and said center electrode, any one of said array of spaced apart electrodes in combination with said center electrode and meter hand forming a capacitor;
- (b) first and second analog switches in electrical communication with each other and one of said spaced apart electrodes;
- (c) third and fourth analog switches in electrical communication with each other and said center electrode;
- (d) a source of constant potential, a resistor and capacitor combination in parallel connection with one another, said resistor and capacitor combination in electrical communication with said fourth switch and said source of constant potential whereby current flowing through said resistor and capacitor combination is proportional to the capacitance formed by any one of said spaced apart electrodes, said center electrode and said rotatable member;
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- (e) a differential amplifier and analog to digital converter, said differential amplifier connected to said analog to digital converter and in electrical communication with said resistor.
Dependencies are inferred from the claim text.