Method and apparatus for capacitive sensing of door position

• US 20070096904A1
• Filed: 01/20/2006
• Published: 05/03/2007
• Est. Priority Date: 11/01/2005
• Status: Active Grant

• Current Assignee: Savi Technology Incorporated
• Original Assignee: Savi Technology Incorporated
• Inventors: Lockyer, Richard, Beauley, David
• Granted Patent: US 7,538,672 B2
• Time in Patent Office: Days
• US Class Current: 340/545.1
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind

Abstract

An apparatus has a sensor with an electrically conductive ground member, electrically conductive first and second parts spaced from and proximate to each other and the ground member, and an insulator disposed between the ground member and the first and second parts. A different configuration involves a tag having circuitry, and a sensor supported on the tag and having electrically conductive first and second parts that are spaced from and proximate to each other, the first and second parts each being electrically coupled to the circuitry.

Claims

1. An apparatus comprising a sensor that includes:

an electrically conductive ground member;

electrically conductive first and second parts spaced from and proximate to each other and said ground member; and

an insulator disposed between said ground member and said first and second parts.

2. An apparatus according to claim 1,

wherein said insulator includes a sheet of insulating material having first and second surfaces on opposite sides thereof;

wherein said ground member is sheetlike and engages said first surface; and

wherein said first and second parts are sheetlike and engage said second surface.

3. An apparatus according to claim 2, wherein said sensor includes two further sheets of insulating material that have therebetween said ground member, said insulator and said first and second parts.

4. An apparatus according to claim 2, wherein said ground member, said insulator and said first and second parts are flexible.

5. An apparatus according to claim 2, wherein said sensor includes electrical connector structure having first and second contacts that are respectively electrically coupled to said first and second parts.

6. An apparatus according to claim 5, wherein said electrical connector structure has a third contact that is electrically coupled to said ground member.

7. An apparatus according to claim 6, wherein said sensor includes first, second and third electrically conductive strips that respectively extend from said first, second and third contacts to said first part, said second part and said ground member;

and wherein said ground member, said insulator, said strips and said first and second parts are all flexible.

8. An apparatus according to claim 7, wherein said first, second and third strips are respectively integral with said first part, said second part and said ground member.

9. An apparatus according to claim 1, including a tag having circuitry therein that is electrically coupled to said first and second parts.

10. An apparatus according to claim 9, wherein said ground member is electrically coupled to said circuitry.

11. An apparatus according to claim 9, wherein said sensor is supported on said tag externally thereof, with said ground member located between said tag and said first and second parts.

12. An apparatus according to claim 11, including a container having a movably supported metal door, said tag being supported on said container so that, as said door moves from a first position to a second position, a portion of said door moves from a position in proximity to said sensor to a position spaced from said sensor.

13. An apparatus according to claim 12, wherein said container has a further movably supported door, said tag being supported on said further door.

14. An apparatus comprising:

a tag having circuitry; and

a sensor supported on said tag and having electrically conductive first and second parts that are spaced from and proximate to each other, said first and second parts each being electrically coupled to said circuitry.

15. An apparatus according to claim 14, including a container having a movably supported metal door, said tag being supported on said container so that, as said door moves from a first position to a second position, a portion of said door moves from a position adjacent said sensor to a position spaced from said sensor.

16. An apparatus according to claim 15, wherein said container has a further movably supported door, said tag being supported on said further door.

17. An apparatus according to claim 14, wherein said sensor further includes:

an electrically conductive ground member that is spaced from and proximate to each of said first and second parts, said ground member being electrically coupled to said circuitry, and being located between said tag and said first and second parts; and

an insulator disposed between said ground member and said first and second parts.

18. An apparatus according to claim 17, wherein said sensor includes two further sheets of insulating material that have therebetween said ground member, said insulator and said first and second parts.

19. A method comprising:

monitoring an electrical characteristic between electrically conductive first and second parts that are spaced from and proximate to each other and an electrically conductive ground member, where an insulator is disposed between said ground member and said first and second parts.

20. A method according to claim 19, including:

selecting as said insulator a sheet of insulating material having first and second surfaces on opposite sides thereof;

configuring said ground member to be sheetlike and to engage said first surface; and

configuring said first and second parts to be sheetlike and to engage said second surface.

21. A method according to claim 20, including configuring said ground member, said insulator and said first and second parts to be flexible.

22. A method according to claim 19, including electrically coupling said first and second parts to circuitry within a tag.

23. A method according to claim 22, including electrically coupling said ground member to said circuitry.

24. A method according to claim 22,

wherein said first and second parts, said ground member and said insulator are respective portions of a sensor;

and

including supporting said sensor on said tag externally thereof, with said ground member located between said tag and said first and second parts.

25. A method according to claim 24, including

providing a container having a movably supported metal door;

and

supporting said tag on said container so that, as said door moves from a first position to a second position, a portion of said door moves from a position in proximity to said sensor to a position spaced from said sensor.

26. A method according to claim 24, including selecting a capacitance characteristic as said electrical characteristic.

27. A method comprising:

providing a tag with a sensor thereon, said sensor having electrically conductive first and second parts that are spaced from and proximate to each other and that are electrically coupled to circuitry within said tag; and

monitoring an electrical characteristic between said electrically conductive first and second parts using said circuitry in said tag.

28. A method according to claim 27, including:

providing a container having a movably supported metal door; and

supporting said tag on said container so that, as said door moves from a first position to a second position, a portion of said door moves from a position adjacent said sensor to a position spaced from said sensor.

29. A method according to claim 27, including configuring said sensor to have:

an electrically conductive ground member that is spaced from and proximate to each of said first and second parts, said ground member being electrically coupled to said circuitry, and being located between said tag and said first and second parts; and

an insulator disposed between said ground member and said first and second parts.

30. A method according to claim 27, including selecting a capacitance characteristic as said electrical characteristic.