Key control system using separate ID and location detection mechanisms

• US 6,812,838 B1
• Filed: 04/26/2002
• Issued: 11/02/2004
• Est. Priority Date: 04/26/2001
• Status: Expired due to Term

• Current Assignee: Key Control Holding Incorporated (Reynolds & Reynolds Company)
• Original Assignee: Keytrak, Inc. (Reynolds & Reynolds Company)
• Inventors: Maloney, William C.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US10/133,130
• Time in Patent Office: 921 Days
• Field of Search: 340/551, 340/568.1, 340/568.7, 340/572.1, 340/572.2, 340/572.4, 340/572.7, 340/572.8, 340/572.9, 340/825.34, 340/825.49, 340/10.1, 340/10.3, 705/28, 705/32, 235/375, 235/383, 235/385, 700/233, 702/141
• US Class Current: 340/568.1
• CPC Class Codes: A47G 29/10 Key holders; Key boards key cases A45C11/32
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G07C 2009/00936 for key cabinets
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00

Abstract

An object control and tracking system and related methods using separate object identification and location detection mechanisms for objects, such as keys, that are maintained in a secure enclosure, such as a key drawer. A plurality of object slots are located on the top tray of the enclosure to receive object tags that include both an RFID tag and an object to be tracked. The objects (e.g., keys) are attached to a portion of the object tags that are outside of the enclosure. Presence detectors are used to determine if an object tag is present in the corresponding slot of the enclosure. RFID sensors located on opposite interior side walls of the enclosure interrogate each RFID tag to determine the presence of each RFID tag within the enclosure. The object control and tracking system includes a controller, a memory for storing an object control database, and related processing logic operating on the controller to control scanning of the presence detectors to determine an object tag'"'"'s presence in a corresponding slot, to identify each object present in the enclosure and to compare the identified objects with an object control database to determine each object removed or replaced since the previous database update.

Claims

1. An object tracking system comprising:

a receptacle having a plurality of slots for storing a plurality of objects, each object having an associated object tag;

at least one first detector for detecting and identifying each object tag present in the receptacle;

a plurality of second detectors separate from said first detector for detecting a location within the receptacle of object tags placed in, or remove from, the receptacle; and

a controller, coupled to the first and second detectors, wherein the controller is programmed to correlate information received from the first and second detectors to identify the particular slot of the receptacle in which each object tag is located.

2. The object tracking system of claim 1 wherein the at least one first detector is an RFID sensor.

3. The object tracking system of claim 2 wherein the RFID sensor comprises a plurality of sensor coils.

4. The object tracking system of claim 2 wherein the RFID sensor comprises a plurality of capacitive plates.

5. The object tracking system of claim 1 wherein the plurality of second detectors includes a switch that is associated with each slot of the receptacle.

6. The object tracking system of claim 5 wherein the switch is a contact switch that closes when an object tag is inserted into the associated slot of the receptacle.

7. The object tracking system of claim 5 wherein the switch is a pair of contacts that are engaged to close an electrical circuit when an object tag is inserted into the associated slot of the receptacle.

8. The object tracking system of claim 5 wherein the switch comprises a photo-conducting switch and a light emitting diode forming a normally closed electrical circuit that is opened when an object tag is inserted into the associated slot of the receptacle.

9. The object tracking system of claim 5 wherein the switch is a reed switch and each object tag includes embedded magnetic material that causes an electrical circuit to close when the object tag is inserted into the associated slot of the receptacle.

10. The object tracking system of claim 1 wherein each object tag comprises an inductive RFID tag.

11. The object tracking system of claim 1 wherein each object tag comprises a capacitive RFID tag.

12. The object tracking system of claim 1 wherein each object tag comprises a key tag.

13. The object tracking system of claim 1 wherein the controller controls the scanning of the at least one first detector to detect the presence or absence of each object tag in the receptacle.

14. The object tracking system of claim 1 wherein the controller controls the scanning of the object tags to determine the locations of the object tags that are present in the receptacle.

15. The object tracking system of claim 14 wherein the controller determines a unique identification code for each inserted object tag and compares each tag identification code with a plurality of entries in an object control database to determine the plurality of object tags present in the receptacle.

16. The object tracking system of claim 1 wherein each object tag includes an anti-collision protocol to enable a plurality of object tags within the receptacle to be interrogated.

17. The object tracking system of claim 1 further comprising a display device.

18. The object tracking system of claim 17 wherein the display device displays to a user each object slot that is empty and each object that is checked out to the user.

19. The object tracking system of claim 17 wherein the display device prompts a user to remove and replace each object tag whose location is determined to be ambiguous.

20. An object tracking system having separate object identification and object location detection mechanisms comprising:

an object control enclosure having a plurality of slots in a top tray of the enclosure for insertion and removal of a plurality of objects, the enclosure including a plurality of side walls and a backplane;

a plurality of object tags, each including an RFID tag and an object, wherein the portion of the object tag including the RFID tag is inserted into a slot in the top tray when an object is returned;

a plurality of presence detectors positioned on the backplane of the object control enclosure for determining the presence or absence of an object tag; and

an RFID sensor to interrogate and identify each RFID tag that is present within the object control enclosure.

21. The object tracking system of claim 20 wherein the RFID sensor comprises a plurality of sensor coils.

22. The object tracking system of claim 20 wherein the RFID sensor comprises a pair of sensor coils.

23. The object tracking system of claim 22 wherein the pair of sensor coils is located on opposite side walls of the object control enclosure.

24. The object tracking system of claim 23 wherein the pair of sensor coils generate a magnetic sensing field between the plurality of side walls of the enclosure.

25. The object tracking system of claim 24 wherein the generated magnetic field is normal to a vertical surface of each object tag in the object control enclosure.

26. The object tracking system of claim 24 wherein the object control enclosure is constructed of metal and shielded to prevent detection of object tags that are located externally to the object control enclosure.

27. The object tracking system of claim 20 wherein the RFID sensor interrogates the plurality of object control tags at frequencies up to about several gigahertz.

28. The object tracking system of claim 20 wherein the plurality of slots in the top tray of the object control enclosure are sized so as to be electrically smaller than the electromagnetic wavelength of an interrogation frequency in order to contain the magnetic field within the enclosure.

29. The object tracking system of claim 20 further comprising a processor, and a memory for storing an object control database.

30. The object tracking system of claim 29 further comprising processing logic that is executed by the processor to identify the insertion or removal of an object.

31. The object tracking system of claim 30 wherein the processing logic controls the scanning of the plurality of presence detectors to detect the presence or absence of an object tag in the enclosure.

32. The object tracking system of claim 29 further comprising a display device.

33. The object tracking system of claim 32 wherein the display device displays to a user each object slot that is empty and each object that is checked out to the user.

34. The object tracking system of claim 32 wherein the display device prompts a user to remove and replace each object tag whose location is determined to be ambiguous.

35. The object tracking system of claim 20 wherein the processing logic controls the scanning of the RFID tags to determine the RFID tags that are present in the enclosure.

36. The object tracking system of claim 35 wherein the processing logic determines a unique identification code for each inserted object tag and compares each tag identification code with a plurality of entries in the object control database to determine the plurality of object tags present in the enclosure.

37. The object tracking system of claim 20 wherein each RFID tag includes an anti-collision protocol to enable a plurality of RFID tags within the RFID sensor field to be interrogated.

38. The object tracking system of claim 20 wherein each of the plurality of presence detectors includes a contact switch having a lever and mounted on the backplane, the contact switch closing when an object tag is inserted into a corresponding slot in the top tray.

39. The object tracking system of claim 20 wherein each of the plurality of presence detectors includes a pair of contacts positioned vertically on the backplane, each object tag including an end portion that is metallic and that causes an electrical circuit to close to indicate presence of each object tag when each object tag is inserted into a corresponding slot in the top tray to a depth sufficient to engage the contacts.

40. The object tracking system of claim 20 wherein each of the plurality of presence detectors includes a photo-conducting switch mounted to the backplane on a first side of a corresponding slot, and a light emitting diode mounted to an opposite side of the corresponding slot, wherein insertion of each object tag into the corresponding slot causes an electrical circuit to open to indicate presence of the object tag.

41. The object tracking system of claim 20 wherein each of the plurality of presence detectors includes a reed switch positioned on the backplane below a corresponding slot in the top tray, each object tag further including embedded magnetic material located in an end portion of the object tag, wherein insertion of each object tag into the corresponding slot causes an electrical circuit to close when the embedded magnetic material is proximate to the reed switch.

42. The object tracking system of claim 20 wherein the plurality of presence detectors are arranged on the backplane in a matrix configuration to indicate a row and a column selection for each object tag inserted into a corresponding slot.

43. The object tracking system of claim 20 further comprising a tag alignment device to ensure proper object tag alignment within a corresponding slot.

44. The object tracking system of claim 43 wherein the tag alignment device comprises an object tag receptacle mounted on the backplane below each corresponding slot in the top tray.

45. The object tracking system of claim 44 wherein the object tag receptacle is fabricated from plastic using an injection molding process.

46. The object tracking system of claim 20 further comprising a pair of tag alignment devices mounted to the top tray to ensure proper object tag alignment within a corresponding slot.

47. The object tracking system of claim 20 wherein each object tag comprises a light emitting diode, an RFID addressable switch and an RFID tag coil, wherein the RFID addressable switch enables an RFID interrogating field to selectively turn on the light emitting diode on the object tag corresponding to the object that a user is trying to identify for removal.

48. The object tracking system of claim 20 wherein the RFID tags comprise inductive RFID tags.

49. The object tracking system of claim 20 wherein the RFID tags comprise capacitive RFID tags.

50. The object tracking system of claim 49 wherein the RFID sensor comprises capacitive plates.

51. The object tracking system of claim 20 wherein the object tags comprise key tags.