Method and apparatus for transmitting power and data using the human body

• US 6,754,472 B1
• Filed: 04/27/2000
• Issued: 06/22/2004
• Est. Priority Date: 04/27/2000
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bathiche, Steven N., Vablais, William, Williams, Lyndsay
• Primary Examiner(s): Gelin, Jean
• Application Number:
  US09/559,746
• Time in Patent Office: 1,517 Days
• Field of Search: 455/40, 455/41, 455/95, 455/100, 455/106, 340/333, 379/55.1, 341/33
• US Class Current: 455/100
• CPC Class Codes: H04B 13/005 Transmission systems in which the medium consists of the human body
• CPC Class Codes: H04Q 9/04 Arrangements for synchronous operation

Abstract

Methods and apparatus for distributing power and data to devices coupled to the human body are described. The human body is used as a conductive medium, e.g., a bus, over which power and/or data is distributed. Power is distributed by coupling a power source to the human body via a first set of electrodes. One or more devise to be powered, e.g., peripheral devices, are also coupled to the human body via additional sets of electrodes. The devices may be, e.g., a speaker, display, watch, keyboard, etc. A pulsed DC signal or AC signal may be used as the power source. By using multiple power supply signals of differing frequencies, different devices can be selectively powered. Digital data and/or other information signals, e.g., audio signals, can be modulated on the power signal using frequency and/or amplitude modulation techniques.

Claims

1. A network of devices comprising:

a first device for generating a first electrical signal;

a second device including first circuitry requiring an electrical signal from an external source to operate, wherein the second device generates initialization information including at least power requirement information; and

a body of a living creature for coupling the first device to the second device and for conducting the electrical signal from the first device to the second device and the initialization information from the second device to the first device, wherein the first and second devices establish a master and a slave relationship there between.

2. The network of claim 1, wherein the first device further comprises:

a first signal generator coupled to the human body for generating the first electrical signal, the first electrical signal having a first frequency.

3. The network of claim 2,

wherein the first frequency is an audible frequency;

and

wherein the first circuitry is a piezo electric speaker which is powered by said first electrical signal.

4. The network of claim 3, wherein the first signal is an analog signal.

5. The network of claim 3, wherein the first signal is a digital signal.

6. The network of claim 1,

wherein the first device includes a signal generator for generating the first electrical signal, the first electrical signal having a first frequency;

and

wherein the second device includes a first passband filter for passing signals in a first frequency range including the first frequency and for blocking signals outside the first frequency range.

7. The network of claim 6,

wherein the second device further includes a power storage device coupled to the passband filter, for storing power from the first electrical signal.

8. The network of claim 6,

wherein said signal generator is capable of generating signals of different frequencies.

9. The network of claim 8, further comprising a third device coupled to said body, the third device including a second passband filter, for passing signals in a second frequency range which includes a second frequency, and for blocking signals of said first frequency.

10. The network of claim 9, wherein the first device further includes:

control circuitry for controlling the signal generator to generate the first electrical signal having said first frequency during a first period of time and to generate a second electrical signal having the second frequency during a second period of time.

11. The network of claim 10, wherein the first and second periods of time are different periods of time.

12. The network of claim 10, wherein the first and second periods of time correspond to overlapping periods of time.

13. The network of claim 10, wherein the third device further includes a second power storage device coupled to the second passband filter for storing power from the second electrical signal.

14. The network of claim 8, wherein the first device further includes:

a modulator for modulating information on said first electrical signal.

15. The network of claim 14, wherein the second device further includes:

transmitter circuitry for transmitting information to the first device over said body.

16. A network device, comprising

power storage device;

a signal generator, coupled to the power storage device, for generating an electrical signal having any one of a plurality of frequencies;

electrodes for coupling the signal generator to a body of a living creature; and

a control circuit for controlling the signal generator to generate a signal as a function of the power requirements of at least one device coupled to said body.

17. The network device of claim 16, wherein the control circuit controls the frequency of the signal being generated by the signal generator.

18. The network device of claim 17, wherein the control circuit further controls the duty cycle of the signal being generated by the signal generator.

19. The network device of claim 16, further comprising:

a communications circuit for generating a communications signal for communicating information to the first device over the body.

20. The network device of claim 19, further comprising:

a modulator for modulating the communications signal on the electrical signal generated by the signal generator.

21. The network device of claim 16, wherein the signal generator includes means for generating a plurality of signals having different frequencies at the same time.

22. The network device of claim 20, wherein the control circuit includes means for controlling the frequency of the signals generated by the signal generator so that at least some of the plurality of generated signals have different frequencies corresponding to the frequencies at which power is supplied to different devices coupled to the body.

23. The network device of claim 22, further comprising:

a data storage device for storing information on the power requirements of multiple devices which can be coupled to the body.

24. The network device of claim 23, wherein the stored information includes the frequency of signals which can be used to supply power to the devices over the body.

25. The network device of claim 23, wherein the stored information includes device power consumption information.

26. The network device of claim 16, further comprising:

a receiver circuit for receiving a signal transmitted using said body as a conductor; and

means for recharging the power storage device from energy included in the signal transmitted using said body.

27. The network device of claim 16, wherein the control circuit includes:

means for measuring the voltage of a signal received from said at least one device; and

means for adjusting at least one of a voltage or duty cycle of the electrical signal as a function of a voltage measurement of said received signal.

28. A device comprising:

a receiver circuit;

electrodes for coupling the receiver circuit to the body of a living creature;

a power storage device coupled to the receiver circuit, for storing power included in a signal received from said body;

a power storage monitoring circuit coupled to the power storage device; and

means for transmitting information regarding device power requirements using said body as a transmission medium.

29. The device of claim 28, wherein the power storage device includes a battery.

30. The device of claim 28, wherein the receiver circuit includes a fitter for passing signals having a frequency within a first frequency range and rejecting signals having a frequency in a second frequency range.

31. The device of claim 30, further comprising:

a signal generator for generating a power supply signal; and

means for supplying said power supply signal to said body.

32. The device of claim 28, further comprising:

a signal generator for generating a power supply signal; and

means for supplying said power supply signal to said body.

33. The device of claim 32, further comprising:

a modulator coupled to said signal generator for modulating an information signal on said power supply signal.

34. The device of claim 33, further comprising:

memory for storing information on power requirements of a plurality of devices which may be coupled to said body.

35. The device of claim 32, wherein said signal generator generates a pulsed direct current signal.

36. The device of claim 32, further comprising:

a control circuit for controlling the frequency of the power supply signal generated by the signal generator.

37. The device of claim 36, wherein the signal generator includes a controllable oscillator.

38. A method of powering a device, comprising:

placing the device in contact with a body of a living creature;

operating the device to receive a power supply signal transmitted using said body as a transmission medium;

operating the device to charge a power storage device included in said device from power included in the received power supply signal;

monitoring the status of the power storage device; and

transmitting a signal including power information using said body as a transmission medium.

39. The method of claim 38, further comprising:

operating the device from the power included in the received power supply signal.

40. The method of claim 39, further comprising:

periodically transmitting device status information using said body as a transmission medium.

41. The method of claim 40, further comprising:

establishing a master/slave control relationship with another device coupled to said body through the use of signals transmitted using said body as a transmission medium.

42. A method of transmitting information to a device coupled to a body of a living creature, comprising:

generating an audio signal;

applying said audio signal to the human body; and

operating the device coupled to said body to receive the audio signal.

43. The method of claim 42, further comprising:

supplying the received audio signal to a speaker.

44. The method of claim 43, the speaker is a piezo electric speaker placed in close proximity to an ear.

45. A digital data storage media, comprising:

computer executable instructions for controlling a device including a processor to perform the steps recited in claim 42.

46. A method of operating a network using a body of a living creature as a bus, comprising:

placing a plurality of devices on said body;

operating a first one of the devices to transmit power to a second one of the devices using the body as a conductive medium;

using the power transmitted to the second one of the devices to power the second device; and

,

establishing a master/slave relationship between a first device placed on said body and devices subsequently placed on said body, the first device placed on said body acting as a bus master.

47. The method of claim 46, further comprising the step of:

transmitting information signals, in addition to said power signal, between the first and second devices using the body as a conductive medium.

48. The method claim 46, further comprising:

modulating an information signal transmitted from the first device to the second device on the power signal transmitted by the first device to the second device.

49. The method of claim 48, further comprising:

transmitting an additional power signal from the first device to a third device coupled to said body, the additional power signal being transmitted at a different frequency than said power signal transmitted from the first device to the second device.

50. A method of transmitting signals between first and second devices coupled to the body of a living creature, comprising:

measuring the voltage of a first electrical signal transmitted from the first device to the second device;

operating the second device to generate a second electrical signal having a voltage or duty cycle which is controlled by the second device as a function of the measured voltage; and

operating the second device to transmit the generated signal to the first device.

51. The method of claim 50, wherein the second device controls the voltage of the second signal to be inversely proportional to the measured voltage.

52. The method 50, wherein the second device controls the voltage of the second signal to be higher when the measured voltage is a first value and to be lower when the measured voltage is a second value, the second value being greater than the first value.

53. The method 50, wherein the second device controls the duty cycle of the second signal to be longer when the measured voltage is a first value and to be shorter when the measured voltage is a second value, the second value being greater than the first value.