Optical data communication and location apparatus, system and method and transmitters and receivers for use therewith

• US 5,633,742 A
• Filed: 09/21/1995
• Issued: 05/27/1997
• Est. Priority Date: 09/21/1994
• Status: Expired due to Fees

• Current Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Original Assignee: Fisher Berkeley Corporation
• Inventors: Shipley, Robert T.
• Primary Examiner(s): PASCAL, LESLIE C
• Application Number:
  US08/532,045
• Time in Patent Office: 614 Days
• Field of Search: 370/10, 375/239, 329/313, 359/185-186, 359/136-137
• US Class Current: 398/118
• CPC Class Codes: G07C 1/10 together with the recording, indicating or registering of other data, e.g. of signs of identity
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00
• CPC Class Codes: G08B 13/248 EAS system combined with another detection technology, e.g. dual EAS and video or other presence detection system
• CPC Class Codes: H04B 10/1149 Arrangements for indoor wireless networking of information

Abstract

An optical data communication and location apparatus for at least one location in a facility having at least one receiver at said at least one location. A plurality of portable transmitters provides optical wireless data links with the receiver. Each of the transmitters has a power supply with circuitry for transmitting data packets over said optical wireless data links to the receiver. The circuitry for transmitting data packets generates a data code having at least two time frames, each of the at least two times frames being divided into at least two data time slots. Each frame has exactly one pulse in one data time slot whereby in each data packet, there is encoded n-bits of binary data where 2ⁿ is equal to the number of time slots in each frame.

Claims

1. An optical data communication and location apparatus for at least one location in a facility comprising at least one receiver at said at least one location, a plurality of portable transmitters providing optical wireless data links with said receiver, each of said transmitters having a portable power supply with means for transmitting data packets over said optical wireless data links to said receiver, said means for transmitting data packets including means for generating a data code having a plurality of time frames, each of said time frames being divided into 2ⁿ data time slots, each frame having therein exactly one pulse in one data time slot whereby in each frame there is encoded n-bits of binary data said receiver including means for sensing the presence of more than one said pulse in a frame and rejecting said data packet.

2. Apparatus as in claim 1 wherein a plurality of locations are provided in the facility with at least one receiver in each location in which transmitters are to be found, said facility including a logic control unit and means for establishing communication between the receivers and the logic control unit.

3. Apparatus as in claim 1 wherein eight data time slots are provided in each frame and where n is equal to three.

4. Apparatus as in claim 1 wherein said power supply is a battery having a 200 milliampere-hour capacity providing sufficient power for the transmitter to permit the transmitter to transmit at two-second intervals for 24 hours a day for approximately one year.

5. Apparatus as in claim 1 wherein said power supply is a battery having a capacity of 200 milliampere-hours and is capable of powering the transmitter with an eight second transmit interval 24 hours per day for approximately three years.

6. Apparatus as in claim 1 wherein each transmitter is provided with a unique identification code and wherein said data packet includes said unique identification code.

7. Apparatus as in claim 1 wherein the timing of a single pulse in the packet is used to encode `n` bits of binary data, where 2ⁿ is the quantity of time slots in a packet frame.

8. Apparatus as in claim 1 wherein each of the transmitters utilizes the same amount of energy for transmitting a packet.

9. Apparatus as in claim 1 wherein said optical energy is infrared energy.

10. Apparatus as in claim 1 wherein the first frame is reserved as a start flag with the remaining frames each encoding three bits of data.

11. Apparatus as in claim 1 wherein said power supply is a battery and wherein said packet includes battery replacement data.

12. Apparatus as in claim 1 wherein each of said plurality of transmitters has a plurality of manually actuatable switches, said switches being coded to provide various types of status information.

13. Apparatus as in claim 1 wherein said data packet has a time duration less than the period of 60 Hz noise signals.

14. Apparatus as in claim 1 including means for encoding the transmitter identification data into the data packets.

15. Apparatus as in claim 1 wherein said means for transmitting packets includes a slow clock and a fast clock, said slow clock being continuously operable for determining the period of transmission of each data packet and a fast clock enabling means coupled to the slow clock for activating the fast clock, said fast clock being only activated during the time that the data packet is to be transmitted to thereby conserve the use of power from the power source.

16. Apparatus as in claim 15 wherein said slow clock and fast clocks have relatively inaccurate time bases.

17. Apparatus as in claim 16 wherein said slow clock includes an oscillator circuit formed of a resistive capacitive network.

18. Apparatus as in claim 16 wherein said fast clock is in the form of an inexpensive ceramic resonator.

19. Apparatus as in claim 1 including means at the receiver for rejecting overlapping data packets where more than one pulse may appear in a frame, data packets having missing pulses and data packets having noise-added pulses whereby each accepted data packet will have exactly one pulse in one time slot in each frame.

20. Apparatus as in claim 1 together with means for preventing successive collisions between data packets including jitter means in each transmitter for transmitting said data packets successively with low accuracy by use of a low tolerance oscillator.

21. Apparatus as in claim 1 wherein said at least one receiver includes means for detecting the amplitude of the energy in the data packet being received permitting said at least one receiver to ascertain which transmitter is closest to said at least one receiver whereby said at least one receiver can decide only to accept a transmission from the transmitter closest to the receiver.

22. An optical data communication and location apparatus for at least one location comprising at least one receiver at said at least one location, a plurality of portable transmitters having the capability of sending data packets of pulses over an optical wireless data link to the receiver, each said transmitters having a power supply, at least one infrared emitter, means connecting the power supply to said at least one infrared emitter to cause data packets to be transmitted by said infrared emitter, said means for transmitting data packets including a slow clock connected to the power supply for providing a successive transmission of packets where the period of time during packet transmission is much shorter than the period of time between successive packet transmissions, a fast clock and fast clock enabling means coupled to the slow clock and to the fast clock for enabling the fast clock means to cause a data packet to be transmitted.

23. Apparatus as in claim 22 wherein said slow clock and said fast clock each have inaccurate time bases.

24. A transmitter for use in an optical data communication and location system for at least one location with at least one receiver at said at least one location comprising a portable case, a printed circuit board mounted in the case, at least one optical emitter mounted in the case and connected to the printed circuit board for emitting optical energy which is visible from the exterior of the case, a power supply connected to the printed circuit board and circuit means mounted on the printed circuit board and coupling the battery to the optical emitter for causing the optical emitter to transmit data packets of data pulses representing bits of binary data, said circuit means including means for generating a data code having a finite number of time frames greater than one, each time frame being divided into a finite number of data time slots greater than one, each frame having therein exactly one pulse in one time slot to encode n-bits of binary data where 2ⁿ is equal to the number of time slots.

25. A transmitter as in claim 24 wherein at least two bits of binary data are supplied with each pulse.

26. A transmitter as in claim 24 wherein said finite number of frames is eight and wherein said finite number of time slots is eight.

27. A transmitter as in claim 24 wherein said circuit means includes a slow clock continuously activated by said power supply for initiating and timing successive transmission of said data packets, said data packets extending over a period of time which is much shorter than the time between successive transmission of data packets, a fast clock for timing said data time slots of a data packet, and enabling means coupled to the slow clock and to the power source for enabling the fast clock only during the time the data packet is being transmitted.

28. A transmitter as in claim 27 wherein said slow clock includes a resistive capacitive timing network and wherein said fast clock includes a ceramic resonator.

29. A transmitter as in claim 27 wherein said circuit means includes means for providing equal power consumption for all transmitted packets of all transmitters.

30. A transmitter as in claim 24 together with an external programming source wherein said circuit means includes identification and data register means, first and second antennas carried by the printed circuit board and the means coupling the first and second antennas to the identification and data register whereby a transmitter can be encoded with identification data from the external programming source.

31. A transmitter as in claim 24 together with a plurality of switches carried by the case and mounted on the printed circuit board and means connecting the switches into the integrated circuit for encoding messages to be incorporated into the data packets being sent by the transmitter.

32. A transmitter as in claim 31 wherein said switches are momentarily actuatable switches.

33. A transmitter as in claim 31 wherein said case has a rectangular configuration having top and bottom and first and second side edges and wherein said switches extend through the second side edge and are adapted to be engaged by a finger of a human hand of the wearer of the transmitter.

34. A transmitter as in claim 33 wherein said case is provided with recesses in the same through which the switches extend.

35. A transmitter as in claim 24 together with means secured to the case and adapt to be secured to the clothing of a wearer.

36. A transmitter as in claim 24 wherein said case has a dimension of approximately 2"×

2" and a thickness of approximately 0.25" and has a weight of less than one ounce.

37. Apparatus as in claim 24 wherein said power source is a battery and wherein said circuit means carried by the printed circuit board includes battery check circuit means for monitoring the remaining life of the battery.

38. A transmitter as in claim 37 wherein said data packet includes information supplied by the battery check circuit means so that each data packet includes information with respect to the remaining battery life of said battery.

39. A transmitter as in claim 24 wherein said optical emitter includes three optical emitters in parallel emitting to ambient atmosphere.

40. A transmitter as in claim 39 wherein said three emitters in parallel provide sufficient energy so that infrared energy can be detected after it has been reflected off of surfaces in the location.

41. A method for supplying packets of pulses over an optical data link from a transmitter to a receiver, the method comprising generating a data packet having at least two time frames with each time frame being divided into at least two data time slots and each frame having therein exactly one pulse in one data time slot to encode n-bits of binary data in the data packet where 2ⁿ is equal to the number of data time slots in each frame, and sensing if there is more than one pulse in a frame and rejecting said data packet.

42. A method for supplying data packets of pulses over an optical data link from one location to another location, the method comprising generating a data packet having a plurality of time frames each time frame being divided into 2ⁿ data time slots, each time frame having therein exactly one pulse in one time slot and encoding n-bits of binary data into each time frame, and sensing whether there is more than one pulse in a frame and if so, rejecting said data packet.

43. A method as in claim 42 together with the step of reserving one of the frames as the start flag.

44. A method as in claim 42 wherein each time frame is provided with nine time slots wherein the first time slot is used as a frame delimiter slot which never contains a data pulse to ensure that there will always be at least one empty time slot between two consecutive pulses.

45. A method as in claim 44 where there are eight frames one of said frames being reserved together with the step using the remaining seven frames to encode three bits of data per frame with a pulse in exactly one of the eight remaining data time slots of each of the seven data frames.

46. A method as in claim 45 wherein said seven frames which encode three bits provide a total of 21 bits of data.

47. A method as in claim 46 for use with status switches wherein the 21 bits of data is comprised of a 16 bit transmitter identity code, a one bit low battery or special function code, a one bit code indicating the programmed transmit interval for the transmitter and a three bit code determined by the status of the status switches.

48. A method as in claim 42 wherein each data time slot occupies approximately 4 microseconds and wherein each data packet comprises a time of 288 microseconds.

49. A method as in claim 48 wherein each of the pulses is two microseconds in width.

50. A method as in claim 49 wherein each pulse is approximately centered in the middle of a four microsecond time slot.