Sensors for monitoring movements, apparatus and systems therefor, and methods for manufacture and use

• US 20070167879A1
• Filed: 12/29/2005
• Published: 07/19/2007
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: Medility, LLC
• Original Assignee: Medility, LLC
• Inventors: Cochran, William
• Granted Patent: US 7,918,801 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/442 Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment

Abstract

Sensors, apparatus, and methods for measuring movements are disclosed. The sensors include input and output windings wound about a common location and an armature is equally positioned relative to both windings movable to vary inductance reactance of the sensor. The mass of the sensor and the ease of movements are such that flexible membranes, such as skin, can be monitored with insignificant interference. The sensor can be included in “Band-aid” bandage arrangement in which the bandage backing can be removed and held in place on skin by the bandage. A monitoring circuit, responsive to the changes in sensor impedance, provides indications of the detected movements. The monitoring circuit includes an arrangement for self-adjusting parameters so that the system can be automatically preset and continually reset. The monitoring circuit includes a power savings-arrangement.

Claims

1. A sensor for monitoring movements comprising a coil including an input winding and output winding each concentrically wound about a common location, and a magnetic core movably extending into the coil for approximately equal positioning relative to both windings, the coil and the core having separate attachments means, the core and the coil forming a loose mechanical coupling there between for free movements of the coil and core relative to each other with insignificant interference.

2. A sensor as defined in claim 1 including circuit means providing a flexible coupling to the input winding adapted to apply electrical signals thereto, and circuit mean providing a flexible coupling to the output winding adapted to receive output signals there from.

3. A sensor as defined in claim 1 wherein the sensor coil is tubular in shape and has a longitudinal axis, the input winding is an excitation winding and the output winding is a pick up winding, and the excitation and pick up windings are concentrically wound to extend along a common portion of the longitudinal sensor axis.

4. A sensor as defined in claim 3 wherein one winding is wound over the other winding.

5. A sensor as defined in claim 3 wherein the two windings are wound together, with wires intertwined so as to occupy a common space.

6. A sensor as defined in claim 1 wherein the sensor coil has a longitudinal axis, the core and coil are free to move relative to each other along the axis, and the coil and core are also free to rotate and wobble about the axis.

7. A sensor as defined in claim 1 wherein the electrical connections to the windings are flexible and extend in a direction generally transverse to the axis so as to provide mechanical decoupling for electrical connections from the movements of the coil.

8. A sensor as defined in claim 7 wherein the input winding is an excitation winding adapted to receive electrical pulses, and the output winding functions as a pick up winding exhibiting output pulses induced from magnetic flux generated by the excitation winding, the magnitude of which is generally proportional to the ratio of the number of turns of wires in each winding and the proportionally is not materially affected by changes in the relative dispositions of the core and the coil.

9. A sensor as defined in claim 8 wherein the amount magnet flux extending between the windings is a function of the disposition of the core relative to the windings, and windings are located relative to each other so that the ratio of the magnetic flux extending between the windings upon the excitation of the input winding remains approximately the same

10. A sensor as defined in claim 8 wherein electrical pulses are adapted to be applied to the excitation winding through a capacitor and wherein the pick up winding provides decaying signals that are a function of the value of the capacitor and the resistive, inductive values of the excitation winding.

11. A sensor as defined in claim 10 wherein the signal from the pick up winding decays to exhibit a polarity change.

12. A sensor comprising a hollow elongated tubular coil unit including input excitation and output pick up windings wound about essentially the same portion of the sensor longitudinal axis and an elongated magnetic core having cross sectional dimensions substantially less than the inside dimensions of the coil unit adapted to extend within the coil unit for approximately the same positioning relative to both the excitation and pick up windings, the core and coil exhibiting a loose mechanical coupling there between wherein coil unit and core are free to move relative to each other along the axis.

13. A sensor as defined in claim 12 wherein electrical signals are adapted to be applied to the excitation winding and the disposition of the windings relative to each other is such that the ratio of magnetic flux between the excitation and pick up windings remains substantially constant as the core moves relatives to the windings.

14. A sensor as defined in claim 12 including separate attachment units connected to the coil unit and the core.

15. A sensor as defined in claim 12 wherein the loose mechanical coupling between the coil unit and core enables the core to rotate and wobble about the longitudinal axis, the movement of the core relative to the coil changes the inductive reactance of the sensor, and the rotation and wobble of the core relative to the coil unit about the axis do not materially impact the inductive reactance of the sensor.

16. A sensor as defined in claim 12 including flexible electrical connections to the windings extending from the coil unit generally transverse to the axis.

17. A sensor as defined in claim 14 wherein the attachment units are adapted to be attached to a flexible substrate, wherein the loose mechanical coupling between the core and the coil creates insignificant interference with the movement of the flexible substrate between attachment units.

18. A sensor as defined in claim 17 wherein the mass of the sensor and the loose coupling between the coil and core are such that enables the sensor to monitor the movements of the flexible membrane with insignificant interference with the movements of the flexible membrane between the attachments.

19. A sensor as defined in claim 18 wherein the flexible membrane is skin and the coil and core move relative to each other along the axis, and rotate and wobble about the axis, to follow deformations in the skin between attachments.

20. A sensor as defined in claim 12 wherein the input and output windings are wound about a common portion of an elongated cylindrical hollow sleeve having a longitudinal axis, the magnetic core is cylindrical in shape and extends into the sleeve for movement within coil along the longitudinal axis, and the input winding is adapted to receive input pulses and the output winding provides output signals in response to the electrical pulses that are a function of the relative disposition of the coil and core.

21. A sensor as defined in claim 12 wherein one winding is wound over the other winding.

22. A sensor as defined in claim 12 wherein the two windings are wound together, with wires intertwined so as to occupy common space.

23. A method of making an electrical inductive sensor comprising the steps of:

providing a hollow elongated tubular shaped bobbin;

winding a coil, having an excitation winding and a pick up winding, concentrically about approximately a common portion of the bobbin and providing flexible connections extending from the windings, and

inserting an elongated magnetic rod having cross sectional dimensions less than the inner dimensions of the bobbin into the coil so that the rod fits loosely within the bobbin and is free to move longitudinally within the coil while keeping approximately the same positioning relative to both the excitation and pick up windings.

24. A method of making an electrical inductive sensor as defined in claim 23 wherein the winding step winds one winding over the other.

25. A method of making an electrical inductive sensor as defined in claim 23 wherein winding step winds both windings intertwined to occupy the common space.

26. A method of making an electrical inductive sensor as defined in claim 23 wherein inserting step includes a rod having cross sectional dimensions that allows the rod to rotate and wobble about the longitudinal movement of the rod.

27. A method of making an electrical inductive sensor as defined in claim 23 including connecting an attachment unit to the coil-bobbin combination, and connecting an attachment unit to the rod.

28. A sensor for monitoring bodily functions comprising at least one sensor having attachment units adapted to be attached to external body skin at two separate locations for providing indications of skin deformation between the two locations, wherein the sensor comprises a coil having an input excitation winding and an output pick up winding and a magnetic core positioned within the coil by a loose mechanical coupling, wherein the core and coil are movable with respect to each other in a generally linear direction to follow deformations of the skin to provide indications in the form of sensor inductive reactance changes as function of the skin deformations and wherein the mass of the sensor and the loose mechanical coupling between the coil and core are such as to insignificantly interfere with the deformation of the skin to be attached between the attachments.

29. A sensor as defined in claim 28 wherein the attachment units are adapted to be attached to the skin locations on the torso and wherein the indications provided by the sensor are a function of breathing.

30. A sensor as defined in claim 28 wherein the sensor is adapted to be attached to the skin locations external the abdomen and wherein the indications provided by the sensor are a function of expansions and contractions of the abdomen.

31. A sensor as defined in claim 30 wherein the windings are formed of thin flexible wires and the wires provide mechanical isolation for electrical connections to the sensor.

32. A sensor as defined in claim 30 wherein the excitation and pick up windings are concentrically wound.

33. A sensor comprising:

two coil units, each comprising a hollow tube having an elongated axis and each coil unit includes input excitation and output pick up windings wound about approximately the same portion of the tube, and the coil units being positioned adjacent to each other end to end along their axis;

two elongated magnetic cores, each positioned within the tube of separate coil units from opposite ends with a loose mechanical coupling wherein the cores and coil units are free to move relative to each other along the elongated axis, and to rotate about the axis, and

an attachment unit extending from each of the cores.

34. A sensor for monitoring movements comprising two coils in the form of an elongated hollow cylinder having a longitudinal axis, and each coil unit having input excitation and output pick up windings wound concentrically along approximately the same portion of the coil cylinder, and a common elongated magnetic core adapted to be inserted into both coil units in a loose mechanical coupling for free movement therein, an attachment unit for the coil units and an attachment unit for the core.

35. A sensor as defined in claim 34 wherein the output windings are connected in series opposition.

36. A sensor as defined in claim 34 wherein the two input windings are connected in series.

37. A sensor as defined in claim 34 wherein the two input windings are connected in parallel.

38. A sensor for receiving electrical pulses from a capacitive signal source for monitoring movements of objects, the sensor comprising at least one coil having an excitation winding adapted to be connected to the signal source and a pick up winding, a core for positioning within the coil, the coil and core being adapted to be attached to the object to be monitored, the pick up winding adapted to provide output signals in response to pulses applied to the excitation winding that are a function of the relative positioning between the coil and core at the time the pulse is applied to the excitation winding, which output signal is in the form of a decaying signal that includes a polarity change.

39. A sensor as defined in claim 38 wherein the values of the source capacitance, the sensor resistance and the sensor inductance as a function of the relative displacement between the coil and core determine the rate of signal decay and the zero crossing exhibited by a polarity change.

40. A sensor for monitoring the deformation of flexible membrane comprising at least one coil having an excitation winding and at least one pick up winding wound in a form of an elongated hollow cylinder and adapted to be attached to a the membrane, and an elongated magnetic core adapted to be inserted into the coil in a loose coupling for free movement therein and adapted to be attached to a different portion of the membrane surface, wherein the inductance of the sensor as sensed by the pick up winding varies as a function of the relative positioning of the core and the coil as the membrane there between deforms, wherein the mass of the coil and core and the free relative movement of the core and the coil being such that the coils and the core move to follow the deformation of the membrane with insignificant interference with the deformation movements of the membrane.

41. A sensor for monitoring bodily functions comprising at least one sensor adapted to be attached to external body skin at two separate locations for providing indications of skin deformation between the two locations wherein the sensor comprises two parts movable with respect to each other in a generally linear direction to follow deformations of the skin and to provides indications in the form of sensor inductive reactance changes as function of the skin deformations and wherein the mass of the sensor and the free movement between the two parts is such as to insignificantly interfere with the deformation of the skin between the two locations.

42. A sensor for monitoring bodily functions as defined in claim 41 wherein the sensor is adapted to be attached to the skin locations on the torso and wherein the indications provided by the sensor are a function of breathing.

43. A sensor for monitoring bodily functions as defined in claim 41 wherein the sensor is adapted to be attached to the skin locations external the abdomen and wherein the indications provided by the sensor are a function of expansions and contractions of the abdomen.

44. A sensor circuit adapted to receive electrical pulses from a capacitive source for monitoring movements of an object comprising:

at least one coil including an input winding and an output winding;

a magnetic core extending into the coil, and

a circuit adapted for connecting the capacitive source to the input winding for applying pulses thereto by discharging through the input winding.

45. A sensor circuit as defined in claim 44 wherein the capacitive value of the source and the inductive and resistive value of the sensor and the relative disposition between the coil and core determine the response of the output winding in the form of a decaying signal having a polarity change.

46. A sensor circuit as defined in claim 44 wherein the coil includes two output windings connected in series opposition, and wherein the position of the core approximately within mid-coil provides an approximate zero indication from the two output windings.

47. A sensor circuit as defined in claim 44 comprising two coils and the core extending into each coil, each coil having an input winding and an output winding, both input windings being adapted to simultaneously receive pulses from the capacitive source, and wherein each output winding provides a decaying signal in response to each pulse that includes a polarity change, wherein the timing ratio between the polarity changes provides an indication of relative displacements of the coil and core.

48. A sensor circuit as defined in claim 44 comprising two coils and the core extending into each coil, each coil having an input winding and an output winding, the output windings connected in series opposition, both input windings being adapted to simultaneously receive pulses from the capacitive source, and wherein each output winding provides a signal in response to each pulse that includes an initial zero crossing and a subsequent zero crossing wherein the integral of the combined output signals between the zero crossings provides an indication of displacement.

49. A sensor circuit as defined in claim 46 wherein the capacitive source includes two capacitors, a separate capacitor connected for charging and discharging through separate input windings.

50. A bandage type sensor for attachment to a flexible membrane for providing indications of deformations of the membrane comprising:

an electrical sensor including two components movable relative to each other to provide indications of displacements there between;

a first bandage layer partially encasing the sensor and provisionally capturing the two sensor components, and

a second layer attached to the bottom of the first layer and readily detachable there from whereby the bandage type sensor is adapted to be attached to a flexible membrane with the sensor released from the first layer.

51. A bandage type sensor as defined in claim 50 wherein the first bandage layer includes a resilient nodular type projection extending from the layer that partially encases the sensor and provisionally captures the sensor components.

52. A bandage type sensor as defined in claim 51 wherein:

the sensor includes a mount extending from each component adapted to be attached to the flexible membrane, and

the nodule captures the sensor mounts so that when the bandage is attached to the membrane the nodule can be to depressed to attach the sensor mounts to the membrane and then released to allow the sensor to monitor contractions and expansions of the membrane.

53. A bandage type sensor as defined in claim 52 wherein the sensor mounts are resiliently captured by extensions formed in the nodule.

54. A bandage type sensor as defined in claim 53 wherein the sensor mounts are captured by the nodule with a weak adhesive.

55. A bandage type sensor as defined in claim 51 wherein the sensor comprises an elongated coil unit and an elongated magnetic core extending through the coil unit for movement along an longitudinal axis of the sensor, the sensor includes mounts at opposite ends of the coil unit and core adapted to be attached by the mounts to the membrane with an adhesive.

56. A bandage type sensor as defined in claim 53 wherein the mounts include an adhesive for attachment to skin.

57. A bandage type sensor as defined in claim 54 wherein mounts are adapted to receive an adhesive before the attachment of the bandage type sensor to skin.

58. A bandage type sensor as defined in claim 53 wherein the nodule is transparent to aid in attachment and provide a visual indication of operation of the sensor.

59. A bandage type sensor as defined in claim 53 wherein the first bandage layer comprises two strips, one on opposite sides of the sensor, generally parallel to the longitudinal axis and with the nodule in between.

60. A bandage type sensor as defined in claim 53 wherein the electrical connection to the sensor avoids mechanical interference with the operation of the sensor.

61. A bandage type sensor as defined in claim 50 wherein the sensor arrangement is included in a sealed package.

62. A method of making a bandage type electrical inductive sensor comprising the steps of:

providing a sensor including two components movable relative to each other to provide indications of displacements there;

providing a first bandage layer to partially encase the sensor, and

attaching a second layer to the bottom of the first layer that is readily detachable there from so that the sensor can be exposed for attachment to a flexible membrane by the first layer.

63. A method of making a bandage type sensor as defined in claim 62 wherein the step for providing a sensor includes a hollow elongated tubular shaped coil and an elongated magnetic rod having a cross section less than the inner dimensions of the coil inserted into the coil and is free to move longitudinally within the coil.

64. A method of making a bandage type sensor as defined in claim 63 including the step of providing a resilient nodular type projection in the first layer for partially encasing the sensor and provisionally capturing the coil and core.

65. A method of making a bandage type sensor as defined in claim 64 including the step of providing a mount extending from the coil and the core that are adapted to be resiliently captured by the projection.

66. A method of making a bandage type sensor as defined in claim 65 wherein the step for including the nodular type projection provides a flexible projection that can resiliently capture the sensor mounts and then flexed to release the sensor.

67. Apparatus for monitoring movements comprising:

a sensor comprising a coil having an input winding and an output winding and a magnetic core extending into the coil for generally linear relative movement there between wherein the inductance of the sensor changes as a function of the relative displacement between the core and the coil, and

a monitoring circuit coupled to the sensor input and output circuits including a circuit for applying pulses to the input circuit, wherein the output circuit provides a decaying signal response for each pulse applied to the input circuit, the rate of decay of the signal being a function of the relative displacement between the coil and core, and the monitoring circuit is responsive to the rate of decay of the sensor output signals for providing indications of the relative displacements between the coil and core.

68. Apparatus as defined in claim 67 wherein the monitoring circuit analyzes the magnitude of the decaying signals at times subsequent to the application of the pulses to the sensor input circuit.

69. Apparatus as defined in claim 67 wherein the monitoring circuit analyzes the 63 at times subsequent to the application of the pulses to the sensor input winding relative to the decaying signal crossover of a selected reference.

70. Apparatus as defined in claim 69 wherein the reference level is a zero voltage crossover level and the monitoring circuit analyzes the magnitude of the decaying signals adjacent to the zero voltage crossover level.

71. Apparatus as defined in claim 67 wherein a capacitor is connected in series with the input winding, and the monitoring circuit applies pulses to the input circuit via the capacitor so that the capacitor discharges through the input winding.

72. Apparatus as defined in claim 67 wherein the monitoring circuit processes a selected range of signals and includes a control circuit for modifying the monitoring circuit operating parameters to adapt the monitoring circuit to variations in the scope of sensor displacements that exceed the selected range.

73. Apparatus as defined in claim 67 including wireless apparatus for communicating the indications of relative displacements to separated apparatus.

74. Apparatus as defined in claim 67 comprising a computer adapted to be coupled to the monitoring circuit for receiving the output signals indicative of sensor displacements and converting the output signals into indications of sensor displacements.

75. Apparatus as defined in claim 68 wherein the monitoring circuit includes a storage circuit for capturing the magnitude values of the decaying signals at the times subsequent to the application of the pulses.

76. Apparatus as defined in claim 67 wherein the monitoring circuit detects the time period after the application of the pulses to the sensor when the magnitude of the decaying signals reaches a selected level for providing an output indicative of sensor displacements.

77. Apparatus as defined in claim 76 wherein the monitoring circuit includes a comparator circuit for determining the timing between the application of the pulses to the sensor and when the magnitudes of the decaying signals reach a selected level.

78. Apparatus as defined in claim 69 wherein the monitoring circuit includes an amplifier for amplifying the decaying signals from the output winding wherein the amplifier is adapted to be driven into saturation and below the reference level, and the monitoring circuit processes a selected range of signals below saturation and above the reference levels, and a control circuit for changing the operating parameters of the monitoring system to adapt the selected range to the scope of sensor displacements.

79. Apparatus as defined in claim 67 wherein the monitoring circuit provides a first gross indication of sensor displacements and a second more sensitive indication of sensor displacements.

80. Apparatus as defined in claim 79 wherein the first gross indications of sensor displacements are variable time based outputs based on selected sensor signal magnitudes, while the second sensitive indications of sensor displacements are variable magnitude sensor outputs based on time.

81. Apparatus for monitoring movements comprising:

an electrical sensor comprising two components wherein one component is adapted to positioned within the other for relative movement there between, and including an input circuit for receiving excitation signals and an output circuit for providing output signals, and

a monitoring circuit coupled to the input and output circuits, including a generator circuit for applying electrical pulses to the input circuit wherein the output circuit provides a decaying signal response for each pulse applied to the input circuit having a decay rate that is a function of the relative displacement between the two sensor components, the monitoring circuit being responsive to the output signal decay rate for providing indications of the relative displacements between the two sensor components, and wherein the monitoring circuit processes a selected range of signals, and includes a control circuit for modifying the monitoring circuit operating parameters to adapt the monitoring circuit to the scope of sensor displacements.

82. Apparatus as defined in claim 81 wherein the sensor comprises a coil having an input winding and an output winding and a magnetic core extending into the coil for generally linear relative movement there between wherein the inductance of the sensor changes as a function of the relative displacement between the core and the coil, and wherein the input and output windings are wound about a common location and the core extends approximately the same amount within both windings.

83. Apparatus as defined in claim 82 wherein the generator circuit includes capacitor is connected in series with the input winding, and the monitoring circuit applies pulses to the input circuit via the capacitor, and the decaying signals exhibit a polarity change.

84. Apparatus as defined in claim 83 wherein the monitoring circuit analyzes the magnitude of the decaying signals at times subsequent to the application of the pulses to the sensor input winding and adjacent to the polarity change in the decaying signals.

85. A method for monitoring movement for use with a sensor that includes at least two movable parts adapted to be attached to separate parts of an object, and wherein the inductance of the sensor varies as a function of the disposition of the two parts relative to each other, the method comprising the steps of:

applying time separated electrical pulses to the sensor, and

analyzing the response of decaying signals from the sensor, the duration of which is a function of the inductance of the sensor to provide an indication of changes in the disposition of the movable parts.

86. A method as defined in claim 85 wherein the analyzing step measures the magnitude of the decaying sensor signals at times between pulses.

87. A method as defined in claim 86 wherein the analyzing steps controls the variable relative timing between the measurement of the magnitude of the decaying signals and the application of timing pulses.

88. A method as defined in claim 87 wherein the analyzing step selects the relative timing for making subsequent measurements when a predetermined level of magnitude is reached.

89. A method as defined in claim 88 wherein the analyzing step comprises the steps of:

amplifying the magnitude of the decaying signals, wherein the response of the amplifier is adapted to reach saturation and fall below zero volts and selecting a predetermined level of amplifier operation for the relative timing below saturation and above zero volts.

90. A method as defined in claim 89 wherein the analyzing step recognizes when the output of the amplifier moves beyond saturation and zero volts to change the relative timing for a predetermined level of amplifier operation for subsequent measurements.

91. A method as defined in claim 90 wherein the analyzing step comprises the steps of:

sampling and storing the output of the amplifier circuit;

converting the stored signal into digital form, and

performing a binary search of the digital signals to determine when the magnitude of the stored signal reaches the predetermined level.

92. A method as defined in claim 86 wherein the object is a flexible membrane.

93. A method as defined in claim 86 wherein the object is skin.

94. A method of monitoring the expansion and contraction of a flexible membrane comprising the steps of:

sensing the expansion and contraction between portions of the membrane in a manner so as to insignificantly interfere with the movements by the membrane there between to produce output electrical signals that are a function of the expansion and contraction between the portions of the membrane, and

processing the outputs signal to provide an indication of the expansion and contraction.

95. A method of monitoring the expansion and contraction of a flexible membrane as set forth in claim 94 wherein:

the sensing step comprises providing a sensor including a hollow elongated tubular shaped coil and an elongated magnetic rod having cross sectional dimensions less than the inner dimensions of the coil inserted into the coil so that the rod fits loosely within the coil and is free to move longitudinally within the coil wherein the inductance of the sensor varies as a function of the dispositions between the core and the coil, attaching the coil to one portion of the membrane, and attaching the core to another portion of the membrane, and

the processing step comprises analyzing the inductance of the combination coil and core to provide a signal corresponding to the expansion and contraction of the membrane.

96. A method of monitoring the expansion and contraction of a flexible membrane as set forth in claim 95 wherein:

the sensing step comprises applying pulse signals to the coil wherein the coil provides output signals that vary as a function of the inductance of the sensor, and

the processing step comprises amplifying the signal, determining whether the amplified signal has been driven into saturation or below a preset level, and modifying the processing step to monitor the signals within saturation and the preset level.

97. Apparatus for use in monitoring internal physiological changes of a body based upon deformations of body skin comprising a sensor including a coil having an input winding and an output winding and a magnetic core extending into the coil, wherein changes in inductive reactance are exhibited by the sensor output winding that are a function of the relative dispositions between the core into the coil, the coil and core being adapted to be attached to body skin at separate points, and a monitoring circuit for applying electrical pulses to the input winding, the monitoring circuit being responsive to the output signals for providing indications of the deformations of the skin.

98. Apparatus as defined in claim 97 wherein the output indicative of skin deformations provides indications of changes in body volume.

99. Apparatus as defined in claim 97 wherein the coil and core form a loose mechanical coupling there between wherein the coil and core follow deformations in the skin with insignificant interference with the skin along the direction of the attachments of the coil and core.

100. Apparatus as defined in claim 99 wherein the electrical connection between the sensor and the monitoring circuit are flexible and extend in a direction of transverse to the sensor displacements.

101. Apparatus as defined in claim 97 wherein the monitoring apparatus processes a selected range of signals, and includes a control circuit for modifying the monitoring apparatus operating parameters to adapt the selected range of signals to the scope of sensor outputs.

102. Apparatus as defined in claim 98 comprising a computer adapted to be coupled to the monitoring circuit for receiving the output there from and converting the output into indications of skin deformation.

103. Apparatus as defined in claim 97 comprising a plurality of sensors attached to body skin for measuring changes in body volume and the monitoring apparatus is responsive to indications from the plurality of sensors for providing outputs indicative of the changes in body volume.

104. Apparatus as defined in claim 103 wherein the plurality of sensors monitor skin deformations in different directions to provide outputs indicative of multi-directional measurements of changes in body volume.

105. Apparatus as defined in claim 98 wherein the monitoring circuit applies electric pulses to the input winding and the output winding outputs decaying signals, the decay rates being a function of the inductive impedance of the sensor, and the monitoring circuit processes the decaying signals to provide indications of skin deformations.

106. Apparatus as defined in claim 105 wherein the capacitive, inductive and resistive components included in the input winding and connections thereto and the change in inductive reactance due to relative coil and core displacements control the rate of delay of the output winding signals.

107. Apparatus as defined in claim 106 wherein the monitoring circuit includes an amplifier for amplifying the decaying signals from the output winding wherein the amplifier is adapted to be driven into saturation and below a reference level and the control circuit changes the parameters of the monitoring system to operate the amplifier between saturation and the reference level.

108. Apparatus as defined in claim 107 wherein the reference level includes a polarity change.

109. A method for monitoring body skin expansions and contractions comprising the steps of non-intrusively physically sensing, in the form of electrical impedance changes, the expansions and contractions between two points on external surface of body skin in a manner so as not to introduce significant interference with the skin expansions and contractions, and converting the changes of impedances into electrical signals that are a function of the skin expansions and contractions.

110. A method as defined in claim 109 including the step of converting the electrical signals into indications of changes in body volume.

111. A method of non-intrusively monitoring bodily functions comprising:

providing a sensor including a coil and a magnetic core extending within the coil;

attaching the coil and core to external body skin for providing indications of skin deformations with insignificant interference with the skin deformations, and

converting the indications of skin deformations into displays thereof.

112. A method as defined in claim 111 wherein the attaching step attaches the sensor coil at one location and core at another location, and the relative movement between the coil and core provides indications of skin deformations between the two locations.

113. A method as defined in claim 112 wherein the attaching step provides linear movement of the coil and core relative to each other as a function of the skin deformations, and wherein the sensor indications are in the form of inductance changes as a function of skin deformations.

114. A method as defined in claim 111 wherein the mass of the sensor provided and the free movement between the coil and core are such as to insignificantly interfere with the deformation of the skin between the two locations.

115. A method as defined in claim 111 wherein the attaching step attaches the sensor coil and core to skin locations adjacent the chest cavity, and wherein the relative movements of the coil and core provide indications that are a function of breathing

116. A method as defined in claim 111 wherein the attaching step attaches the sensor coil and core to skin locations of the abdomen and, wherein the relative movements of the coil and core provide indications that are a function of expansions and contractions within the abdomen.

117. A sensor system for monitoring the displacement between movable parts of an object comprising:

an electrical sensor comprising two components, one component being adapted to be positioned within the other for generally linear movement there between, and having input and output circuits, wherein the electrical impedance of the sensor changes as a function of the relative displacement between the components, the components of the sensor being adapted to be attached to different movable parts of the object for providing impedance changes corresponding to displacements;

a circuit for applying pulses to the input circuit wherein the output winding outputs decaying signals, the rate of decay being a function of the relative displacement between the components, and

a monitoring circuit is responsive to the output signal decay rate for providing indications of the displacements between the movable parts of the object.

118. A sensor system as defined in claim 117 wherein the sensor components comprises a coil having an input winding and an output winding and a magnetic core extending into the coil for generally linear relative movement there between wherein the inductance of the sensor changes as a function of the relative displacement between the core and the coil, the coil and core being adapted to be attached to different movable parts of the object.

119. A sensor system as defined in claim 118 wherein the monitoring circuit detects the time between the application of a pulse to the input winding and when the decaying signal reaches a preset level, and converts the measured time to provide an output indicative of the displacements between the movable parts.

120. A sensor system as defined in claim 119 wherein the monitoring circuit comprises a timing circuit activated after the application of pulses to the sensor, and a comparator circuit for comparing the decaying signal to a reference, and interrupting the timing circuit when a comparison is reached.

121. A sensor system as defined in claim 118 wherein the monitoring circuit comprises a circuit for measuring the amplitude of the decaying signal after the application of the pulses to the sensor as an indication of the displacements.

122. A sensor system as defined in claim 118 wherein the monitoring circuit detects the time between the application of pulses to the sensor and when sensor output response reaches a preset level, and detects the magnitude of the sensor output at a time subsequent to the application of the pulses, and includes a processor for converting the measured time and the measured magnitude to provide first and second outputs indicative of displacement between the movable parts.

123. A sensor system as defined in claim 118 wherein the monitoring circuit includes a processor for processes a selected range of signals, and includes a control circuit for modifying the operation parameters of the monitoring circuit to adapt the selected range of signals to sensor to the scope of sensor operation.

124. A sensor system as defined in claim 118 wherein the object being monitoring is a flexible membrane and wherein a loose mechanical coupling is provided between the coil and core so that insignificant interference is applied to the flexible substrate by the relative movement between the coil and the core and the monitoring circuit provides indications of the deformations of the flexible substrate between the attachments of the coil and core.

125. A sensor system as defined in claim 121 wherein the monitoring circuit includes a storage circuit for storing the magnitudes of the decaying signals at selected times subsequent to the application of the electrical pulses.

126. A sensor system as defined in claim 125 wherein the monitoring circuit varies the relative timing between the application of the electrical pulses and the operation of the storage circuit.

127. A sensor system as defined in claim 126 wherein the monitoring circuit comprises:

a circuit for amplifying the magnitude of the decaying signals and applying the value of the amplified signals at controlled times to the storage circuit;

a circuit for sensing when the values of the decaying signals from the amplifying circuit are in saturation or below a reference level, and

the control circuit is responsive to the sensing circuit to adjusts the controlled times in a direction so that the amplifier circuit operates between saturation and the reference level.

128. A sensor system as defined in claim 127 comprising:

an analog to digital converter circuit for converting the magnitudes of the storage circuit to digital form, and

the control circuit performs an analysis of the digital signals to determine when the magnitudes of the decaying signals fall within saturation and reference level operating range of the amplifying circuit.

129. A sensor system as defined in claim 128 wherein the control circuit determines when the magnitudes of the decaying signals from the amplifier approach saturation or the reference level for varying the relative timing between the application of the electrical pulses and the operation of the storage circuit.

130. A sensor system as defined in claim 129 comprising apparatus for providing a visual display of the magnitudes of the decaying signals stored in the storage circuit as an indication of the displacement between the movable portions of the object.

131. Monitoring apparatus for use with a sensor that includes at least two movable parts adapted to be attached to separate parts of an object, and wherein the electrical impedance of the sensor varies as a function of the disposition of the two parts relative to each other, the apparatus comprising:

a circuit for applying time separated electrical pulses to the sensor, and

a circuit for analyzing the response of the sensor to the electrical pulses in the form of a decaying signals, the duration of which is a function of the impedance of the sensor, to provide an indication of changes in the disposition between the movable parts.

132. Monitoring apparatus as defined in claim 131 wherein the analyzing circuit measures the magnitude of the decaying sensor signals at selected times between pulses.

133. Monitoring apparatus as defined in claim 131 wherein the timing between the application of the pulses and the time of measurement of the magnitude of the decaying signals is variable.

134. Monitoring apparatus as defined in claim 131 wherein the analyzing circuit selects the timing for making subsequent measurements so that the level of magnitudes is within a predetermined range.

135. Monitoring apparatus as defined in claim 134 wherein the analyzing circuit comprises:

an amplifier circuit for amplifying the magnitude of the decaying signals, wherein the response of the amplifier is adapted to be driven into non-linear operation, and

wherein the predetermined range of magnitudes for selecting the timing falls within the linear operation of the amplifier.

136. Monitoring apparatus as defined in claim 135 wherein the analyzing circuit determines when the output of the amplifier is driven near the non-linear operation of the amplifier to change the timing for subsequent measurements.

137. Monitoring apparatus as defined in claim 134 wherein the analyzing circuit comprises:

a sample and hold circuit for sampling and storing the output of the amplifier circuit at selected times subsequent to the application of the pulses;

an analog to digital converter circuit for converting the output of the sample and hold circuit to digital form, and

a processor for performing a binary analysis of the digital signals to determine when the magnitudes of the output of the sample and hold circuit fall within a selected range of digital signals.

138. Monitoring apparatus as defined in claim 131 wherein the object is a flexible membrane.

139. Monitoring apparatus as defined in claim 131 wherein the object is skin.

140. Monitoring apparatus as defined in claim 131 wherein the sensor includes a coil and a ferromagnetic core adapted to be located for movement within the coil, the coil and core being adapted to be attached to separate movable parts of an object, and the inductive reactance of the sensor varies as a function of the disposition of the coil and core relative to each other over the scope of movements, and wherein the analyzing circuit includes a control circuit programmed to process a range of signals from the sensor and for resetting the operation parameters of the analysis circuit in the event the sensor inductive reactance changes exceed the range.

141. Monitoring apparatus as defined in claim 140 where the analyzing circuit comprises an amplifier and the control circuit monitors the output of the amplifier circuit to determine when the range of amplified signals exceeds the linear operation of the amplifier for resetting the parameters of the analyzing circuit for amplifier linear operation.

142. Monitoring apparatus as defined in claim 141 wherein the amplifier is a variable gain amplifier, and the control circuit monitors the output of the amplifier circuit to modify the gain of the amplifier if the amplifier operates at levels approaching saturation or zero.

143. Circuit apparatus for use with a sensor that includes at least two movable parts adapted to be attached to separate movable parts of an object, and wherein the electrical impedance of the sensor varies as a function of the disposition of the two parts relative to each other, the apparatus comprising:

a monitoring circuit responsive to changes in sensor impedance to provide signals the magnitude of which is a function of the impedance exhibited by the sensor;

a processing circuit coupled to receive the signals to provide an output signals indicative of the displacement of the parts, and

a control circuit for controlling the operating parameters of the monitoring circuit to conform its operation with the scope of impedance changes exhibited by the sensor.

144. Circuit apparatus as defined in claim 143 wherein:

the monitoring circuit comprises a circuit for applying periodic pulses to the sensor, an amplifier circuit for amplifying the response of the sensor to the pulses, a storage circuit for storing the magnitude of the amplifier output at selected timings, a timing circuit for controlling the timing between the application of pulses and storing magnitudes, and an analog to digital converter circuit for converting the magnitude into digital form;

the processing circuit processes a selected range of digital signals from the monitoring circuit, and

the control circuit controls the operating parameter of at least one of the timing circuit and amplifier circuit.

145. Circuit apparatus as defined in claim 143 wherein:

the monitoring circuit comprises a circuit for applying periodic pulses to the sensor, a timer circuit initiated after the application of pulses to the sensor, a comparator circuit comparing the output of the sensor with a reference to stop the count of the timer circuit, and an analog to digital converter circuit for converting the count to digital form;

the processing circuit processes a selected range of digital signals from the monitoring circuit, and

the control circuit conforms the operation of the monitoring circuit within the range of selected digital signals.

146. A power savings arrangement for a monitoring apparatus for use with an electrical displacement sensor system comprising:

a power supply connected to provide power to the monitoring apparatus;

a generator circuit coupled to the sensor for applying electrical pulses to the sensor;

a first timing circuit coupled to the generator circuit for controlling the timing at which the generator circuit applies pulses to the sensor;

a data processing circuit coupled to receive output signals from the sensor including a data processing sequence for converting the sensor output signals into digital form, the data processing circuit having a signal processing rate that is substantially shorter than the timing between the application of pulses to the sensor, and

a second timing circuit coupled to the data processing circuit having a timing rate substantially greater than the first timing circuit operable upon the application of a pulse to the sensor for a duration sufficient to enable the data processing circuit to complete a data processing sequence, and then deactivating to place the data processing circuit in a lower power consumption mode thereby reducing the drain on the power supply.

147. A power savings arrangement as defined in claim 146 wherein the first timing circuit is responsive to start signals to initiate the data processing sequences of the monitoring apparatus, and wherein the second timing circuit is activated by the initiation of the data processing sequence and is deactivated after the completion of the data processing sequence.

148. A power savings arrangement as defined in claim 146 wherein the sensor is adapted to be coupled between separate parts of an object, the data processing unit includes an analysis circuit that stores the magnitude of the sensor output signals at a time subsequent to the application of a pulse to the sensor, and a processor circuit responsive to the stored signal from the analysis circuit to provide digital signals indicative of the movement of the object parts, and wherein the data processing sequence of the analysis and processing circuits are activated by the second timing circuit from a lower power consumption mode of operation to a higher mode of operation and upon completion of a data processing sequence become deactivated to the lower power consumption mode when the second timing circuit is deactivated.

149. A power savings arrangement as defined in claim 148 wherein:

the analysis circuit amplifies the sensor output signals and applies the amplified signals to an analog memory circuit that is latched by the second timing circuit to store the magnitude of the sensor output signals in memory at a time subsequent to the application of the pulses to the sensor, and

an analog to digital converter circuit operable by the second timing circuit coupled to the memory circuit to convert the magnitude of the signals stored in memory into digital form.

150. A power savings arrangement as defined in claim 149 wherein the analysis circuit includes an amplifier circuit adapted to be activated for operation at the start of a data processing sequence and deactivated for stand by operation in a reduced power consumption state upon the completion of a data processing sequence.

151. A power savings arrangement as defined in claim 149 wherein the processor includes a microcontroller having digital signal processing circuitry therein operable a the start of a data processing sequence by the second timing circuit and switches to a substantially reduced power consumption mode of operation when the data processing sequence is complete when the second timing circuit is deactivated.

152. A power savings method of operating sensing apparatus including a sensor and a monitoring circuit for analyzing the output of the sensor comprising the steps of:

initiating a test cycle of the sensing apparatus by applying a first timer circuit output pulse to the sensor;

enabling a second timer circuit to apply timing pulses to the monitoring circuit at a rate that is substantially greater than the first timer pulse rate so that the monitoring circuit is enabled to process the output from the sensor at a time substantially shorter than the first timer pulse rate, and

disabling the second timer from applying pulses to the monitoring circuit until a subsequent test cycle is initiated.

153. A power savings method as defined in claim 152 including the step of preconditioning the monitoring circuit for processing the output from the sensor when a test cycle is initiated.