Wireless surface acoustic wave-based proximity sensor, sensing system and method
First Claim
1. A wireless proximity sensor for sensing the position of an object comprising:
- a) a body formed of a substrate material having an upper surface, a lower surface, a first end and a second end;
b) at least one interdigital transducer provided on a surface of the body, wherein each of the at least one interdigital transducers has at least one first antenna associated therewith;
c) at least one sensing element formed of magnetostrictive material provided on the substrate material;
d) at least one magnet operatively positioned with respect to the body for providing a reference point of a position of an object, wherein the at least one magnet is adapted and configured to induce a magnetic field in the at least one sensing element; and
e) a means for attaching disposed between the at least one magnet and a first side surface of the at least one sensing element, such that the at least one magnet and the first side surface of the at least one sensing element are connected, allowing for movement of the at least one magnet in relation to the at least one sensing element.
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Abstract
The subject invention is related to wireless proximity sensor and sensing system for detecting the position of an object. The system includes a transceiver for providing wireless communication with a passive wireless surface acoustic wave (SAW) proximity sensor. The wireless proximity sensor receives a wireless signal from the transceiver, which powers the SAW device and in turn transmits a signal back to the transceiver that includes information about the position of an object. The wireless proximity sensor uses one or more SAW devices with a sensing element made of magnetostrictive material, in conjunction with one or more magnets and one or more targets that are positioned relative to an object. The movement of the target(s) in relation to the proximity sensor operatively produces a mechanical response due to the shift in the magnetic field of the sensing element. The sensing element in turn enhances the magnetic field of the SAW device to which it is attached, and this information is transmitted to the transceiver as information about the position of an object.
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Citations
25 Claims
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1. A wireless proximity sensor for sensing the position of an object comprising:
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a) a body formed of a substrate material having an upper surface, a lower surface, a first end and a second end; b) at least one interdigital transducer provided on a surface of the body, wherein each of the at least one interdigital transducers has at least one first antenna associated therewith; c) at least one sensing element formed of magnetostrictive material provided on the substrate material; d) at least one magnet operatively positioned with respect to the body for providing a reference point of a position of an object, wherein the at least one magnet is adapted and configured to induce a magnetic field in the at least one sensing element; and e) a means for attaching disposed between the at least one magnet and a first side surface of the at least one sensing element, such that the at least one magnet and the first side surface of the at least one sensing element are connected, allowing for movement of the at least one magnet in relation to the at least one sensing element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A wireless proximity sensing system comprising:
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a) a body formed of a substrate material having an upper surface, a lower surface, a first end and a second end; b) at least one interdigital transducer provided on a surface of the of the body, wherein each of the at least one interdigital transducers has at least one first antenna associated therewith; c) at least one sensing element formed of magnetostrictive material deposited on the substrate material between the first end and the second end; d) at least one magnet operatively positioned with respect to the body for providing a reference point of a position of an object, wherein the at least one magnet is adapted and configured to induce a magnetic field in the at least one sensing element; e) an attaching member disposed between the at least one magnet and a first side surface of the at least one sensing element, such that the at least one magnet and the first side surface of the at least one sensing element are connected, allowing for movement of the at least one magnet in relation to the at least one sensing element; f) a transceiver adapted and configured to generate a query signal to request information about a position of an object; and g) a second antenna for wirelessly receiving information about a position of an object from and transmitting information to the transceiver to the at least one first antenna. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for wirelessly detecting the position of an object comprising:
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a) providing at least one SAW device having a sensing element adapted to produce a mechanical response in the at least one SAW device in response to a change in a magnetic field of the sensing element; b) providing at least one magnet movable relative to the sensing element and adapted to produce a change in the magnetic field of the sensing element based on movement of the at least one magnet; c) positioning at least one moveable target relative to the object so that movement of the at least one moveable target causes movement in the at least one magnet; d) wirelessly powering the at least one SAW device; and e) detecting information indicative of the mechanical response in the at least one SAW device relative to a change in the magnetic field of the sensing element, indicating the position of the object. - View Dependent Claims (22, 23, 24, 25)
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Specification