US 2003/0141866 A1 · Proximity sensor device that determines at least one physical characteristic of an item

Abstract

A sensor device includes the ability to determine part presence and at least one physical characteristic of the part. A drive coil and sense coil are arranged so that a voltage applied across the drive coil causes a response in the sense coil, which is influenced by the presence of the item of interest. In a first mode, a controller determines whether the item is present by determining an amount of coupling between the drive coil and the sense coil, which is indicative of whether a part is present near the sense coil. In a second mode, the controller determines an amount of magnetic flux that is indicative of a thickness of the material. In another mode, constant current applied to the drive coil instigates a voltage across both coils. The amplitude of the sense coil voltage and a phase shift of the sense coil voltage relative to the drive coil voltage provides material thickness information.

Claims17

Dependent claims

A device for sensing the presence and at least one physical characteristic of an item, comprising:

a power source;
a drive coil selectively coupled to the power source;
a sense coil associated with the drive coil such that the sense coil is responsive to a voltage applied to the drive coil by the power source and influenced by the presence of a ferrous item near to the sense coil;
and
a processor that processes an output from the sense coil in a first mode to make a determination whether an item is present near the sensing device and in a second mode to make a determination regarding the physical characteristic of the item.

2 more elements

Dependencies are inferred from the claim text.

Proximity sensor device that determines at least one physical characteristic of an item

Life of this patent

Proximity sensor device that determines at least one physical characteristic of an item

Life of this patent

Abstract

Claims17