Wireless detection of motion

• US 20070107666A1
• Filed: 11/16/2005
• Published: 05/17/2007
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: Vertex Pharmaceuticals Incorporated
• Original Assignee: Vertex Pharmaceuticals Incorporated
• Inventors: Vuong, Minh, Salzmann, Philip, Flores, Javier, Nguyen, Trang, Wallace, Matthew, Silos-Santiago, Ada, Bian, Di
• Granted Patent: US 8,955,458 B2
• Time in Patent Office: Days
• US Class Current: 119/421
• CPC Class Codes: A01K 1/031 Cages for laboratory animals; Cages for measuring metabolism of animals
• CPC Class Codes: A01K 29/005 Monitoring or measuring activity, e.g. detecting heat or mating

Abstract

Disclosed herein are systems and methods for detecting motion of an object, such as the paw of rat. A tag comprising an inductive element and a capacitive element may be attached to the object and the motion detected by monitoring the affect of the tag on a time-varying magnetic field.

Claims

1. A system for detecting motion of a tag, comprising:

a coil configured for generating a time-varying magnetic field;

a tag comprising an inductive element and a capacitive element positioned with respect to said coil such that tag motion moves said tag relative to said coil.

2. The system of claim 1, wherein said system comprises a four-coil inductive bridge, wherein said coil comprises one leg of said bridge.

3. The system of claim 2, additionally comprising a signal generator coupled to opposite nodes of said bridge.

4. The system of claim 3, additionally comprising a sensing circuit coupled to opposite nodes of said bridge.

5. The system of claim 1, wherein said tag comprises an inductor and a capacitor electrically coupled in parallel.

6. The system of claim 5, wherein said signal generator is adapted to drive said coil with an AC current having a frequency, and wherein said electrically coupled inductor and capacitor have a resonant frequency approximately equal to said AC frequency.

7. A system for detecting motion of a tag, comprising:

a means for generating a time-varying magnetic field;

a means for sensing a change in said time-varying magnetic field; and

a tag, said tag comprising an LC circuit for causing a change in said time-varying magnetic field when said tag is in motion within said time-varying magnetic field.

8. A system for detecting motion of a tag, comprising:

a sensing coil comprising a wire wound into a coil, said coil defining a perimeter;

an AC generator electrically coupled to said wire;

a circuit electrically coupled to said wire, said circuit adapted to detect a change in AC current flowing through said wire; and

a tag, said tag comprising an inductive element and a capacitive element, wherein said tag is within the perimeter of said coil but not necessarily coplanar with said coil, and wherein when said tag is in motion, the motion causes a change in any AC current flowing through said wire.

9. The system of claim 8, wherein said tag comprises an inductor and a capacitor electrically coupled in parallel.

10. The system of claim 9, wherein said AC generator is adapted to drive said sensing coil with an AC current having a frequency, and wherein said electrically coupled inductor and capacitor have a resonant frequency approximately equal to said AC frequency.

11. The system of claim 8, wherein said circuit comprises a four-coil inductive bridge, wherein said sensing coil comprises one leg of said bridge.

12. The system of claim 11, wherein said AC generator is electrically coupled to two nodes of said bridge.

13. The system of claim 12, wherein said circuit comprises a differential amplifier electrically coupled to two other nodes of said bridge.

14. The system of claim 11, wherein said circuit comprises a differential amplifier electrically coupled to said bridge.

15. The system of claim 14, wherein said circuit comprises a rectifier electrically coupled to said differential amplifier.

16. A tag for monitoring motion of a paw on a rodent, comprising:

an inductor and capacitor electrically coupled in parallel; and

a paw mount coupled to said inductor and capacitor.

17. A method of detecting motion of an object, comprising:

exposing a tag comprising an inductive element and a capacitive element to a time-varying magnetic field; and

detecting a change in said time-varying magnetic field caused by motion of said tag within said magnetic field.

18. The method of claim 17, wherein said tag comprises an inductor and a capacitor electrically coupled in parallel.

19. The method of claim 17, wherein said time-varying magnetic field is generated by passing an AC current having a frequency through a coil.

20. The method of claim 19, wherein said tag comprises an inductor and a capacitor electrically coupled in parallel that have a resonant frequency approximately equal to said AC frequency.

21. The method of claim 19, wherein said detection is facilitated by a detection circuit electrically coupled to said coil.

22. The method of claim 21, wherein said circuit comprises a four-coil inductive bridge, wherein said coil comprises one leg of said bridge.

23. The method of claim 17, wherein said object comprises a paw on a rodent.

24. A method of assaying for an anti-nociceptive drug, comprising:

attaching a tag to a paw of the rodent, said tag comprising an inductive element and a capacitive element;

administering a potential anti-nociceptive drug to a rodent;

exposing said paw to a nociceptive stimulus;

exposing said tag to a time-varying magnetic field; and

monitoring motion of said paw by detecting a change in said time-varying magnetic field induced by motion of said tag within said field.

25. The method of claim 24, wherein said rodent is a rat.

26. The method of claim 24, wherein said paw is a rear paw of said rodent.

27. The method of claim 24, wherein said tag comprises an inductor and a capacitor electrically coupled in parallel.

28. The method of claim 24, wherein said time-varying magnetic field is generated by passing current having an AC frequency through a coil.

29. The method of claim 28, wherein said tag comprises an inductor and a capacitor electrically coupled in parallel that have a resonant frequency substantially similar to said AC frequency.

30. The method of claim 28, wherein said detection is facilitated by a detection circuit electrically coupled to said coil.

31. The method of claim 30, wherein said circuit comprises a four-coil inductive bridge, wherein said coil comprises one leg of said bridge.

32. The method of claim 24, wherein the step of exposing said paw to said nociceptive stimulus comprises injecting said paw with formalin.