Method and apparatus for self-powered vehicular sensor node using magnetic sensor and radio transceiver

• US 7,388,517 B2
• Filed: 02/19/2005
• Issued: 06/17/2008
• Est. Priority Date: 03/01/2004
• Status: Expired due to Fees

• Current Assignee: Sensys Networks Inc. (Tagmaster AB)
• Original Assignee: Sensys Networks Inc. (Tagmaster AB)
• Inventors: Kavaler, Robert
• Primary Examiner(s): Crosland; Donnie L
• Application Number:
  US11/062,130
• Publication Number:
  US 20050190077A1
• Time in Patent Office: 1,214 Days
• Field of Search: 340/941, 340/933, 340/928
• US Class Current: 340/941
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors
• CPC Class Codes: G08G 1/14 indicating individual free spaces in parking areas
• CPC Class Codes: G08G 1/141 with means giving the indication of available parking spaces
• CPC Class Codes: G08G 1/145 where the indication depends on the parking areas

Abstract

Vehicular sensor node, circuit apparatus and their operations are provided. Power from a power source is controlled for delivery to radio transceiver and magnetic sensor, based upon a task trigger and task identifier. The radio transceiver and the magnetic sensor are operated based upon the task identifier, when the task trigger is active. The power source, radio transceiver, magnetic sensor, and circuit apparatus are enclosed in vehicular sensor node, placed upon pavement and operating for at least five years without replacing the power source components. Magnetic sensor preferably uses the magnetic resistive effect to create magnetic sensor state. Radio transceiver preferably implements version of a wireless communications protocol. The circuit apparatus may further include light emitting structure to visibly communicate during installation and/or testing, and second light emitting structure used to visibly communicate with vehicle operators. Making filled shell and vehicular sensor node from circuit apparatus.

Claims

1. A method of sensing the presence of a vehicle, comprising the steps of:

maintaining a clock count to create a task trigger and a task identifier;

controlling power from a power source delivered to a radio transceiver and a magnetic sensor based upon said task trigger and said task identifier; and

operating said radio transceiver and said magnetic sensor based upon said task identifier, when said task trigger is active; and

wherein said power source, said radio transceiver, and said magnetic sensor are enclosed in a vehicular sensor node to operate for at least five years without replacement of said power source using said method.

2. The method of claim 1, wherein said power source, said radio transceiver, and said magnetic sensor are enclosed in a vehicular sensor node to operate for at least ten years without replacement of any component of said power source using said method.

3. The method of claim 1, wherein the step controlling said power, further comprises the step of:

providing a transceiver power delivered to said radio transceiver when said task trigger is active and said task identifier indicates at least one of a sensor report and a clock-alignment.

4. The method of claim 1, wherein the step controlling said power, further comprises the step of:

providing a sensor power delivered to said magnetic sensor when said task trigger is active and said task identifier indicates a sensor reading.

5. The method of claim 1, wherein the step of controlling said power further comprises the steps of:

minimizing said power from said power source delivered to said radio transceiver and said magnetic sensor, when said task trigger is inactive; and

distributing said power from said power source delivered to said radio transceiver and said magnetic sensor based upon said task identifier, when said task trigger is active.

6. The method of claim 1, wherein the step of operating comprises the steps of:

using a magnetic sensor state of said magnetic sensor responding to said presence of said vehicle to create a sensed vehicle state, when said task identifier indicates a sensor reading;

sending said vehicle sensed state by said radio transceiver, when said task identifier indicates a sensor report; and

receiving a global clock count from said radio transceiver to confirm-update said clock count, when said task identifier indicates a clock-alignment.

7. The method of claim 6, wherein the step of sending, comprises the step of:

sending said vehicle sensed state by said radio transceiver to create a received vehicle state at an access point; and

wherein the step of receiving, comprises the step of;

said radio transceiver receiving said global clock count from said access point.

8. A circuit apparatus for sensing said presence of said vehicle implementing the method of claim 1, comprising:

means for maintaining said clock count to create said task trigger and said task identifier;

means for controlling said power from said power source delivered to said radio transceiver and said magnetic sensor based upon said task trigger and said task identifier; and

means for operating said radio transceiver and said magnetic sensor based upon said task identifier, when said task trigger is active.

9. The circuit apparatus of claim 8, wherein said power source includes at least one battery.

10. The circuit apparatus of claim 9, wherein said power source further includes at least one solar cell.

11. The circuit apparatus of claim 8, wherein said magnetic sensor has a primary sensing axis for sensing said presence of said vehicle used to create said magnetic sensor state.

12. The circuit apparatus of claim 8, wherein said magnetic sensor uses a form of the magnetic resistive effect to create said magnetic sensor state.

13. The circuit apparatus of claim 12, wherein said magnetic sensor includes an at least two axis magneto-resistive sensor to create said magnetic sensor state.

14. The circuit apparatus of claim 13, wherein said magnetic sensor includes a two axis magneto-resistive sensor to create said magnetic sensor state.

15. The circuit apparatus of claim 14, wherein said magnetic sensor includes a three axis magneto-resistive sensor to create said magnetic sensor state.

16. The circuit apparatus of claim 8, wherein said radio transceiver implements a version of at least one wireless communications protocol.

17. The circuit apparatus of claim 16, wherein said wireless communications protocol includes the IEEE 802.15.4 communications standard.

18. The circuit apparatus of claim 16, wherein said radio transceiver uses at least one channel of said wireless communications protocol.

19. The circuit apparatus of claim 18, wherein said radio transceiver uses a second of said channels of said wireless communications protocol to communicate with a vehicle radio transceiver associated-attached to said vehicle.

20. The circuit apparatus of claim 8,

wherein said means for maintaining, comprises:

a clock timer controllably coupled to a computer to deliver said task trigger and said task identifier, and communicatively coupled with said computer to communicate said clock count;

wherein said means for controlling, comprises;

a power control circuit coupled with said radio transceiver, and coupled with said magnetic sensor to deliver said power;

wherein said means for operating, comprises;

said computer controllably coupled to said power circuit, said radio transceiver, and said magnetic sensor; and

said computer accessibly coupled with a memory containing a program system including the program step of;

operating said radio transceiver and said magnetic sensor based upon said task identifier, when said task trigger is active.

21. The circuit apparatus of claim 20, wherein the program system further comprises the program step of:

controlling power from said power source delivered to said radio transceiver and said magnetic sensor based upon said task trigger and said task identifier, comprising the program steps of;

minimizing said power from said power source delivered to said radio transceiver and said magnetic sensor, when said task trigger is inactive; and

distributing said power from said power source delivered to said radio transceiver and said magnetic sensor based upon said task identifier, when said task trigger is active.

22. The circuit apparatus of claim 21, wherein the program step of distributing is further comprises the steps of:

delivering a transceiver power to said radio transceiver, when said task identifier indicates said radio transceiver is used; and

delivering a sensor power to said magnetic sensor, when said task identifier indicates said magnetic sensor is used.

23. The circuit apparatus of claim 20, wherein the program step of operating comprises the program steps of:

using a magnetic sensor state of said magnetic sensor responding to said presence of said vehicle to create a sensed vehicle state, when said task identifier indicates a sensor reading;

sending said vehicle sensed state by said radio transceiver, when said task identifier indicates a sensor report; and

receiving a global clock count from said radio transceiver to confirm-update said clock count, when said task identifier indicates a clock-alignment.

24. The circuit apparatus of claim 8, further comprising at least one of:

a light emitting structure visibly arranged perpendicular to a primary sensing axis of said magnetic sensor; and

a second of said light emitting structures visibly arranged parallel to said primary sensing axis for communicating with a vehicle operator.

25. The circuit apparatus of claim 24, wherein said means for controlling further comprises:

means for controlling said power from said power source delivered to at least one said light emitting structure and said second light emitting structure based upon said task trigger and said task identifier.

26. The circuit apparatus of claim 25, wherein said means for operating further comprises:

means for visibly communicating with said light emitting structure when said task trigger is active and when said task identifier indicates a feedback task using said light emitting structure; and

wherein said means for controlling, comprises;

means for visibly signaling with said second light emitting structure when said task trigger is active and when said task identifier indicates communicating with said vehicle operator.

27. The circuit apparatus of claim 26, wherein said means for visibly communicating with said light emitting structure, further comprises:

means for receiving a probe node address from said radio transceiver; and

means for visibly communicating with said light emitting structure using said probe node address; and

wherein said means for means for visibly signaling with said second light emitting structure, further comprises;

means for visibly signaling with said second light emitting structure when said task trigger is active and when said task identifier indicates communicating with said vehicle operator for a pedestrian.

28. The circuit apparatus of claim 27, where said means for visibly communicating using said probe node address, further comprises at least one of:

means for visibly communicating when a node address equals said probe node address;

means for visibly communicating when said node address does not equal said probe node address;

means for visibly communicating when said node address is less than said probe node address; and

means for visibly communicating when said node address is greater than said probe node address.

29. The circuit apparatus of claim 8, wherein the means for operating, comprises:

means for using said magnetic sensor state of said magnetic sensor responding to said presence of said vehicle to create said sensed vehicle state, when said task identifier indicates said sensor reading;

means for sending said vehicle sensed state by said radio transceiver, when said task identifier indicates said sensor report; and

means for receiving said global clock count from said radio transceiver to confirm-update said clock count, when said task identifier indicates said clock-alignment.

30. The circuit apparatus of claim 8, wherein at least one of said means for maintaining, said means for controlling, and said means for operating, comprises at least one of a finite state machine, a field programmable logic device, and a computer.

31. The circuit apparatus of claim 8, wherein a single integrated circuit includes at least two of said means for maintaining, said means for controlling, and said means for operating.

32. The circuit apparatus of claim 31, wherein a single integrated circuit includes each of said means for maintaining, said means for controlling, and said means for operating.

33. The circuit apparatus of claim 31, wherein said single integrated circuit includes at least one of said magnetic sensor and said radio transceiver.

34. The circuit apparatus of claim 8, further comprising an antenna coupled with said radio transceiver.

35. The circuit apparatus of claim 34, wherein said antenna is a patch antenna.

36. A filled shell for said vehicular sensor node, comprising said circuit apparatus of claim 34 enclosed in a plastic shell, said plastic shell filled with a filler.

37. Said vehicular sensor node of claim 36, comprising said filled shell glued to said pavement.

38. A method of making said vehicular sensor node of claim 8, comprising the steps of:

enclosing said circuit apparatus in a plastic shell filled with a filler to create a filled shell; and

gluing said filled shell to a locally flat surface to create said vehicular sensor node.

39. The vehicular sensor node and said filled shell, as products of the process of claim 38.