Self-Energized Wireless Sensor and Method Using Magnetic Field Communications

• US 20130017783A1
• Filed: 07/13/2012
• Published: 01/17/2013
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: University of Connecticut (State of Connecticut)
• Original Assignee: University of Connecticut (State of Connecticut)
• Inventors: Gao, Robert X., Sah, Sripati
• Granted Patent: US 8,971,801 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

Manufacturing processes monitor forces or pressures within a machine. Metal within machines affect wireless communications within the machines for reporting monitored data. An embodiment of the present invention is a sensor that provides wireless communications unaffected by metals and with less electrical noise than slip rings. An embodiment can monitor manufacturing processes, such as by employing a piezoelectric transducer to measure forces or pressures in a machine and generate an electrical signal representing, for example, forces measured by the piezoelectric transducer. A threshold modulator circuit converts the electrical signal into a series of electrical pulses, which can be transmitted as a corresponding series of magnetic field pulses to a wireless receiver. The receiver reconstructs the original electrical signal, thereby enabling a receiver system to determine physical activities in the machine. The embodiment may be self-powered through use of power generated by the piezoelectric transducer.

Claims

1. A method of transmitting information via a wireless medium, the method comprising:

converting an electrical signal representing information into a series of electrical pulses; and

generating a series of magnetic field pulses corresponding to the series of electrical pulses to transmit a representation of the information via a wireless medium.

2. The method of claim 1, further comprising:

receiving the series of magnetic field pulses via the wireless medium; and

reconstructing the information based on the series of magnetic field pulses received.

3. The method of claim 1, wherein the electrical signal is a representation of a physical force or pressure.

4. The method of claim 1, wherein the electrical signal is an analog waveform.

5. The method of claim 1, wherein the series of magnetic field pulses is a digital waveform.

6. The method of claim 1, further comprising resolving the series of electrical pulses using n-levels, wherein n is based on a largest expected amplitude divided by a minimum amplitude detection level of the electrical signal.

7. The method of claim 1, further comprising operating in a self-powered manner.

8. The method of claim 1, wherein converting the electrical signal employs a threshold modulator circuit including a silicon bidirectional switch, thyristor, and resistor.

9. The method of claim 8, further comprising enabling the resistor to be selectively programmed.

10. The method of claim 8, further comprising enabling automated control of the threshold modulator circuit to change the resolution and range of the transmission, said automated control receiving instructions via a wireless medium.

11. The method of claim 1, further comprising employing a force-to-electrical transducer to produce the electrical signal.

12. The method of claim 11, wherein the force-to-electrical transducer is a piezoelectric transducer.

13. The method of claim 11, wherein converting the electrical signal includes employing a threshold modulator circuit and generating a series of magnetic field pulses includes employing an inductive transmitter, and further comprising supporting bidirectional current flow around a loop that includes the transducer, threshold modulator circuit, and inductive transmitter.

14. A circuit comprising:

an input port and an output port;

a resistor having a first lead and a second lead;

a silicon bidirectional switch electrically coupled in series with the input port and the first lead of the resistor; and

a thyristor having its voltage control input coupled in series with the second lead of the resistor and its current flow path coupled in series with the input port and the output port.

15. The circuit of claim 14, wherein the resistor, silicon bidirectional switch, and thyristor compose a threshold modulator circuit, and wherein the circuit is configured to receive an electrical signal at the input port, and convert the electrical signal to a series of electrical pulses using the threshold modulator circuit.

16. The circuit of claim 15, further comprising a transmitter component coupled to the output port configured to generate a series of magnetic field pulses corresponding to the series of electrical pulses.

17. The circuit of claim 16, further comprising a receiver component configured to receive the series of magnetic field pulses via a wireless medium from the transmitter component.

18. The circuit of claim 15, wherein the electrical signal is a representation of a physical force or pressure.

19. The circuit of claim 15, wherein the electrical signal is an analog waveform.

20. The circuit of claim 15, wherein the electrical signal is a digital waveform that represents information.

21. The circuit of claim 15, wherein the circuit is configured to resolve the series of electrical pulses using n-levels, wherein n is based on a largest expected amplitude divided by a minimum amplitude detection level of the electrical signal.

22. The circuit of claim 15, further comprising a force-to-electrical transducer coupled to the input port and providing an electrical signal to the threshold modulator circuit as a function of force or pressure.

23. The circuit of claim 22, wherein the force-to-electrical transducer is a piezoelectric transducer.

24. The circuit of claim 22, wherein the force-to-electrical transducer, threshold modulator circuit, and transmitter component form a loop around which current flow is bidirectional.

25. The circuit of claim 14, wherein the resistor is configured to be selectively programmed.

26. The circuit of claim 16, wherein the circuit is configured to enable automated control over the range and resolution of the series of magnetic field pulses by receiving instructions from a wireless medium.

27. The circuit of claim 14, wherein the circuit is self-powered.

28. A communications system comprising:

a transducer configured to produce an electrical signal representative of an applied force or pressure;

a threshold modulator circuit coupled to the transducer and configured to convert the electrical signal to a series of electrical pulses; and

a transmitter coupled to the threshold modulator circuit and configured to convert the series of electrical pulses to a series of magnetic field pulses and transmit the series of magnetic field pulses via a wireless medium.

29. The communications system of claim 28, wherein the threshold modulator circuit includes a silicon bidirectional switch, a resistor, and a thyristor.

30. The communications system of claim 29, wherein the resistor is configured to be selectively programmed.

31. The communications system of claim 28, wherein the communication system is powered by energy generated by the transducer from the application of the force or pressure.

32. The communications system of claim 28, wherein the transducer is a piezoelectric transducer.

33. The communications system of claim 28, further comprising:

a receiver configured to receive the series of magnetic field pulses transmitted wirelessly via the wireless medium; and

a signal reconstruction circuit configured to determine the force or pressure from the series of magnetic field pulses.

34. The communications system of claim 28, wherein the electrical signal is a digital waveform that represents information.

35. The communications system of claim 28, further configured to resolve the series of electrical pulses using n-levels, wherein n is based on a largest expected amplitude divided by a minimum amplitude detection level of the electrical signal.

36. The communications system of claim 28, wherein the threshold modulator circuit is configured to convert the electrical signal into a series of electrical pulses and the transmitter is configured to generate a series of magnetic field pulses as a function of the series of electrical pulses, wherein the communication system is configured to support a bidirectional current flow around a loop that includes the transducer, threshold modulator circuit, and inductive transmitter.

37. The communications system of claim 33, wherein the electrical signal is a first electrical signal and the series of electrical pulses is a first series of electrical pulses and wherein the communications system further comprises a signal reconstruction circuit configured to convert the series of magnetic field pulses into a second series of electrical pulses and the second series of electrical pulses into a second electrical signal, the second electrical signal approximating the first electrical signal.

38. A communications system, comprising:

means for converting an electrical signal into a series of electrical pulses;

means for generating a series of magnetic field pulses corresponding to the series of electrical pulses; and

means for transmitting the series of magnetic field pulses via a wireless medium.

39. A non-contact slip ring, comprising:

an interior member comprising;

a transducer configured to produce an electrical signal representation of measured data;

a threshold modulator circuit coupled to the transducer configured to convert the electrical signal to a series of electrical pulses; and

a transmitter coupled to the threshold modulator circuit configured to convert the series of electrical pulses to a corresponding series of magnetic field pulses and transmit the series of magnetic field pulses via a wireless medium; and

an exterior member comprising;

a receiver configured to receive the series of magnetic field pulses from the transmitter via the wireless medium; and

a signal reconstruction circuit configured to determine the force or pressure as a function of the series of magnetic field pulses received.