Electro-mechanical transducer

Abstract

An electro-mechanical transducer is disclosed for measuring physical parameters such as vibration, acceleration or the angular orientation of an object to which it is attached. A closed container partially filled with a fluid, has a light source and light detector mounted in optical communication with the container's interior. The arrangement of the detector and light source is such that light from the source must pass at least once through the surface (i.e., air-fluid interface) of the fluid before being detected. A constant incident light intensity is provided within the chamber and the resultant transmitted light is measured by the detector and an associated meter circuit. As the container is vibrated, or the angular relationship of the surface of the liquid with respect to the detected light rays is varied, the light transmissive and refractive properties of the liquid surface are altered, thereby altering the output of the light detector.

What is claimed is: 
     
       1. An electro-mechanical transducer comprising: a container;   a liquid partially filling said container thereby defining a liquid surface therewithin.Iadd., at least a portion of said surface having a substantially constant slope when said container is quiescent.Iaddend.;   a source of electromagnetic radiation mounted with respect to said container so as to illuminate at least a portion of the interior thereof;   an electromagnetic radiation detection means responsive to said source, mounted with respect to said container so as to detect radiation after interaction with said liquid surface within said container, movement of said container causing the output of said detection means to vary as a result of the changing transmissive and refractive properties of said liquid surface; and   means for directing the radiation from said source so that substantially all of the radiation passes at least once through said liquid surface before impinging on said detection means .Iadd.and a line connecting said source and detection means passes through said liquid surface constant slope portion.Iaddend..   
     
     
       2. Apparatus as in claim 1 wherein said source is an incandescent light bulb. 
     
     
       3. Apparatus as in claim 1 wherein said source is a light emitting diode. 
     
     
       4. Apparatus as in claim 1 wherein said source is an infrared radiation source. 
     
     
       5. Apparatus as in any of claims 1-4 wherein said liquid is water. 
     
     
       6. Apparatus as in any of claims 1-4 wherein said liquid is alcohol. 
     
     
       7. Apparatus as in any of claims 1-4 wherein said liquid is oil. 
     
     
       8. Apparatus as in any of claims 1-4 wherein said detection means is a photoelectric cell. 
     
     
       9. Apparatus as in any of claims 1-4 wherein said detection means is a photoresistive cell. 
     
     
       10. Apparatus as in any of claims 1-4 wherein said detection means is a phototransistor. 
     
     
       11. Apparatus as in claim 1 wherein: said container is opaque to electromagnetic radiation of a particular frequency range;   said source produces radiation at least partially within said frequency range; and   said detection means is responsive to radiation at least partially within said frequency range.   
     
     
       12. Apparatus as in claim 1 further comprising at least one of a first set of fiber optics directing radiation from said source to a plurality of locations within said container, and a second set of fiber optics directing radiation from a plurality of locations within said container to said detection means so that said output variation represents the average change in the transmissive and refractive properties of said surface. 
     
     
       13. Apparatus as in claim 1 wherein the area of said liquid surface illuminated by said source is at least mostly out of the area of said liquid surface viewed by said detection means so that as said container vibrates, said surface becomes more uneven, thereby refracting more of the radiation from said source into said detection means. 
     
     
       14. Apparatus as in claim 1 wherein: said source and detection means are substantially entirely on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incident on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       15. Apparatus as in claim 1 wherein said source and said detection means are substantially entirely disposed on opposite sides of said liquid surface. 
     
     
       16. A vibration detector system comprising: a container;   a source of electromagnetic radiation mounted in said container so as to illuminate at least a portion of the interior thereof;   a liquid partially filling said container thereby defining a liquid surface therewithin, said liquid being at least partially transparent to said radiation;   electromagnetic radiation detection means responsive to said source, mounted on said container so as to detect radiation after interaction with said liquid surface within said container, for producing a signal proportional to the radiation incident on said detection means;   means for directing the radiation from said source so that substantially all of the radiation passes at least once through said liquid surface before impinging on said detection means; and   means responsive to said detection means for processing said signal into a more useful form of data so that as said detection means vibrates, the light transmissive properties of the surface of said liquid are altered, causing said signal and said data to be correspondingly altered.   
     
     
       17. Apparatus as in claim 16 wherein said processing means comprises: amplifying means for amplifying said detection means signal; and   means for displaying the amplified signal in a visually meaningful form.   
     
     
       18. Apparatus as in claim 17 wherein said displaying means comprises at least one of an ammeter and a voltmeter. 
     
     
       19. Apparatus as in claim 17 wherein said displaying means comprises an oscilloscope. 
     
     
       20. Apparatus as in claim 16 wherein: said container is opaque to electromagnetic radiation of a particular frequency range;   said source produces radiation at least partially within said frequency range; and   said detection means is responsive to radiation within said frequency range.   
     
     
       21. Apparatus as in claim 16 wherein: said source and said detection means are both mounted on the same side of said liquid surface;   said means for directing comprises mirror means mounted to said container on the side of said liquid surface opposite said source and said detection means for reflecting radiation from said source to said detection means; and   the aperture angle of said source and the detection angle of said detection means are limited so that substantially all of the radiation detected by said detection means has passed at least once through said surface.   
     
     
       22. Apparatus as in claim 16 wherein said source and said detection means are mounted on opposite sides of said liquid surface. 
     
     
       23. Apparatus as in claim 22 wherein: said container is cylindrical; and   said source and said detection means are mounted on opposite ends of said cylindrical container and at substantially diametrically opposed respective positions on said opposite ends.   
     
     
       24. Apparatus as in claim 22 wherein the area of said liquid surface illuminated by said source is substantially offset from the area of said liquid surface viewed by said detection means so that as said container vibrates, said surface becomes more turbulent, thereby refracting more of the radiation from said source into said detection means. 
     
     
       25. Apparatus as in claim 16 further comprising at least one of a first set of fiber optics directing radiation from said source to a plurality of locations within said container, and a second set of fiber optics directing radiation from a plurality of locations within said container to said detection means so that said output variation represents the average change in the transmissive and refractive properties of said surface. 
     
     
       26. Apparatus as in claim 16 wherein: said source and detection means are on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incident on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       27. An electro-mechanical device for leveling an object comprising: a container;   a liquid partially filling said container thereby defining a liquid surface therewithin.Iadd., at least a portion of said surface having a substantially constant slope when said container is quiescent.Iaddend.;   a source of electromagnetic radiation mounted in said container so as to illuminate at least a portion of the interior thereof;   electromagnetic radiation detection means responsive to said source, mounted in said container so as to detect radiation after interaction with said liquid surface within said container, for producing a signal related to the radiation incident on said detection means;   means responsive to said detection means for processing said signal to provide an output corresponding to the orientation of said container; and   means for mounting said container so that said source is entirely on one side of the liquid surface of said liquid while said detection means is entirely on the other side of said surface .Iadd.and a line connecting said source and detection means passes through said liquid surface constant slope portion.Iaddend..   
     
     
       28. Apparatus as in claim 27 wherein said processing means comprises: amplifying means for amplifying said detection means signal; and   means for displaying the amplified signal in a visually meaningful form.   
     
     
       29. Apparatus as in claim 28 wherein said displaying means is at least one of an ammeter and a voltmeter. 
     
     
       30. Apparatus as in claim 27 wherein: said container is opaque to electromagnetic radiation of a particular frequency range;   said source produces radiation at least partially within said frequency range; and   said detection means is responsive to radiation within said frequency range.   
     
     
       31. Apparatus as in claim 27 wherein said means for mounting positions the axis between said source and said detection means vertically when said object is positioned at the desired angular orientation thereby resulting in a maximum signal from said detection means. 
     
     
       32. An electro-mechanical accelerometer comprising: a container;   a liquid partially filling said container thereby defining a liquid surface therewithin.Iadd., at least a portion of said surface having a substantially constant slope when said container is quiescent.Iaddend.;   a source of electromagnetic radiation mounted in said container so as to illuminate at least a portion of the interior thereof;   electromagnetic radiation detection means responsive to said source, mounted in said container so as to detect radiation after interaction with said liquid surface within said container, for producing a signal related to the radiation incident on said detection means;   means for mounting said container so that the axes of said source and said detection means are both vertical .[.and.]..Iadd., .Iaddend.lie along the same line.Iadd., and pass through said liquid surface constant slope portion.Iaddend.; and   means connected to said detection means for processing said signal to provide an accurate indication of acceleration.   
     
     
       33. Apparatus as in claim 32 wherein: said container is opaque to electromagnetic radiation of a particular frequency range;   said source produces radiation at least partially within said frequency range; and   said detection means is responsive to radiation within said frequency range.   
     
     
       34. Apparatus as in claim 32 wherein said processing means comprises: amplifying means for amplifying said detection means signal; and   means for displaying the amplified signal in a visually meaningful form.   
     
     
       35. Apparatus as in claim 34 wherein said displaying means is at least one of an ammeter and a voltmeter. 
     
     
       36. A seismograph comprising: at least one of a plate and pole positioned upon a solid foundation for amplifying earth tremors;   a container rigidly mounted on said at least one of a plate and pole;   a liquid partially filling said container thereby defining a liquid surface therewithin;   a source of electromagnetic radiation mounted with respect to said container so as to illuminate at least a portion of the interior thereof;   an electromagnetic radiation detection means responsive to said source, mounted with respect to said container so as to detect substantially only the radiation having passed at least once through said liquid surface within said container, for producing a signal related to the radiation incident on said detection means; and   means responsive to said detection means for processing said signal to represent a detected earth tremor.   
     
     
       37. Apparatus as in claim 36 wherein: said container is opaque to electromagnetic radiation of a particular frequency range;   said source produces radiation at least partially within said frequency range; and   said detection means is responsive to radiation within said frequency range.   
     
     
       38. Apparatus as in claim 36 wherein said processing means comprises: amplifying means for amplifying said detection means signal; and   means for displaying the amplified signal in a visually meaningful form.   
     
     
       39. Apparatus as in claim 38 wherein said means for displaying comprises a graph recorder which records said amplified current over time. 
     
     
       40. Apparatus as in claim 36 wherein: said source and said detection means are both mounted on the said side of said liquid surface;   said apparatus further comprises mirror means mounted with respect to said container on the side of said liquid surface opposite said source and said detection means for reflecting radiation from said source to said detection means; and   the aperture angle of said source and the detection angle of said detection means are limited so that substantially all of the radiation detected by said detection means has passed at least once through said surface.   
     
     
       41. Apparatus as in claim 36 further comprising means for mounting said container so that said source and said detection means are on opposite sides of said liquid surface. 
     
     
       42. Apparatus as in claim 41 wherein: said container is cylindrical; and   said source and said detection means are mounted on opposite ends of said cylindrical container and at substantially diametrically opposed positions on said ends.   
     
     
       43. Apparatus as in claim 41 wherein the area of said liquid surface illuminated by said source is substantially offset from the area of said liquid surface viewed by said detection means so that as said container vibrates, said liquid surface becomes more turbulent, thereby refracting more of the radiation from said source into said detection means. 
     
     
       44. Apparatus as in claim 36 further comprising at least one of a first set of fiber optics directing radiation from said source to a plurality of locations within said container, and a second set of fiber optics directing radiation from a plurality of locations within said container to said detection means so that said output variation represents the average change in the transmissive and refractive properties of said liquid surface. 
     
     
       45. Apparatus as in claim 36 wherein: said source and detection means are on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incident on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       46. A vibration detector system comprising: a container;   a source of electromagnetic radiation mounted on said container so as to illuminate at least a portion of the interior thereof;   a liquid partially filling said container thereby defining a liquid surface therewithin, said liquid being at least partially transparent to said radiation in the quiescent state;   electromagnetic radiation detection means responsive to said source, mounted on said container so as to detect radiation after interaction with said liquid surface within said container, for producing a signal related to the radiation incident on said detection means;   means for mounting said container so that said source and said detection means are entirely disposed on opposite sides of said liquid surface;   the area of said liquid surface illuminated by said source being substantially offset from the area of said liquid surface viewed by said detection means; and   means responsive to said detection means for processing said signal to indicate the vibration of said container.   
     
     
       47. Apparatus as in claim 46 wherein said processing means comprises: amplifying means for amplifying said detection means signal; and   means for displaying the amplified signal in a visually meaningful form.   
     
     
       48. Apparatus as in claim 47 wherein said displaying means comprises at least one of an ammeter and a voltmeter. 
     
     
       49. Apparatus as in claim 47 wherein said displaying means comprises an oscilloscope. 
     
     
       50. Apparatus as in claim 46 wherein; said container is opaque to electromagnetic radiation of a particular frequency range;   said source produces radiation at least partially within said frequency range; and   said detection means is responsive to radiation within said frequency range.   
     
     
       51. Apparatus as in claim 46 wherein: said container is cylindrical; and   said source and said detection means are mounted on opposite ends of said cylindrical container.   
     
     
       52. A method of transforming mechanical movement of an object to an electrical signal comprising the steps of: mounting a container partially filled with a liquid on said object thereby defining a liquid surface therewithin.Iadd., at least a portion of said surface having a substantially constant slope when said container is quiescent.Iaddend.;   directing a source of electromagnetic radiation into said container; and   photo-electrically detecting .Iadd.with detection means .Iaddend.variations in the intensity of substantially only the radiation having passed at least once through said liquid surface, incident after interaction with said liquid surface on an area in said container with detection means, .Iadd.a line connecting said source and detection means passing through said liquid surface constant slope portion, .Iaddend.said variations being caused by changes in the transmissive and refractive properties of the surface of said liquid induced by movement of said container.   
     
     
       53. A method as in claim 52 wherein the area of said liquid surface illuminated by said source is substantially offset from the area of said liquid surface viewed by said detection means so that as said container vibrates, said surface becomes more turbulent, thereby refracting more of the radiation from said source into said detecting means. 
     
     
       54. A method as in claim 52 wherein: said source and detection means are on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incident on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       55. A method as in claim 52, further comprising at least one of the steps of directing radiation from said source to a plurality of locations within said container with a first set of fiber optics, and directing radiation from a plurality of locations within said container to said detection means with a second set of fiber optics so that said output variations represents the average change in the transmissive and refractive properties of said surface. 
     
     
       56. A method of detecting vibrations in an object comprising the steps of: mounting a container partially filled with a liquid on said object thereby defining a liquid surface therewithin;   directing a source of electromagnetic radiation into said container and through said liquid surface;   detecting variations in the intensity of substantially only the radiation, having passed at least once through said liquid surface, incident on an area in said container with detection means, said variations being caused by changes in the transmissive and refractive properties of said liquid surface upon vibration of said container; and   electrically processing the detected variations to indicate detected vibration of said object.   
     
     
       57. A method as in claim 56 wherein: said directing step and said detecting steps are performed on the same side of said liquid surface and   said directing step comprises the steps of reflecting said radiation on the other side of said liquid surface toward the site of said detecting step.   
     
     
       58. A method as in claim 56 wherein said directing step and said detecting step occurs on opposite sides of said liquid surface. 
     
     
       59. A method as in claim 58 wherein the area of said liquid surface illuminated by said source is substantially offset from the area of said liquid surface viewed by said detection means so that as said container vibrates, said surface become more turbulent, thereby refracting more of the radiation from said source into said detection means. 
     
     
       60. A method as in claim 56 wherein: said source and detection means are on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incidence on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       61. A method as in claim 56 further comprising the steps of: directing radiation from said source to a plurality of locations within said container with a first set of fiber optics; and   directing radiation from a plurality of locations within said container to said detection means with a second set of fiber optics so that said output variation represents the average changes in the transmissive and refractive properties of said surface.   
     
     
       62. A method of detecting vibrations in an object comprising entirely the steps of: mounting a container partially filled with a liquid on said object thereby defining a liquid surface therewithin;   directing a source of electromagnetic radiation into said container and through said liquid surface;   detecting variations in the intensity of radiation after passage through said liquid surface;   said directing and detecting steps occurring on opposite sides of said liquid surface and the area of said liquid surface illuminated by said source being substantially offset from the area of said liquid surface viewed during said detecting step so that as said container vibrates, said surface becomes more turbulent thereby refracting more of the radiation from said source into said detection means; and   processing the detected variations to represent the detected vibration of said object.   
     
     
       63. A method of angularly adjusting the position of an object comprising the steps of: mounting a container partially filled with a liquid on said object thereby defining a fluid surface therewithin.Iadd., at least a portion of said surface having a substantially constant slope when said container is quiescent.Iaddend.;   directing a source of electromagnetic radiation into said container .Iadd.entirely .Iaddend.from one side of said liquid surface;   detecting .Iadd.with detection means .Iaddend.variations in the intensity of incident radiation at a location entirely on the other side of said liquid surface.Iadd., a line connecting said source and detection means passing through said liquid surface constant slope portion.Iaddend.;   processing the detected variations to represent a predetermined characteristic signal when said object is positioned at a corresponding predetermined angular orientation; and   moving said object until said signal achieves said predetermined characteristic.   
     
     
       64. A method as in claim 63 wherein said detecting step senses a maximum intensity of radiation when said object is positioned at the desired angular orientation. 
     
     
       65. A method of measuring the acceleration of an object comprising the steps of: mounting a container partially filled with a liquid on said object defining a liquid surface therewithin.Iadd., at least a portion of said surface having a substantially constant slope when said container is quiescent.Iaddend.;   directing a source of electromagnetic radiation into said container; and   detecting .Iadd.with detection means .Iaddend.variations in the intensity of substantially only the radiation, having passed at least once through said liquid surface, .Iadd.a line connecting said source and detection means passing through said liquid surface constant slope portion, said variations .Iaddend.caused by changes in the refractive and transmissive properties of said liquid surface as a result of the variations in the acceleration-influenced angle of said liquid surface.   
     
     
       66. A method as in claim 65 wherein said detecting step detects radiation along a vertical axis so that as said container accelerates, the change in the angular relationship of the surface of said liquid to the vertical produces said variations. 
     
     
       67. A method of measuring earth tremors comprising the steps of: positioning at least one of a plate and pole upon a solid foundation in order to amplify said tremors;   rigidly mounting a container partially filled with a liquid on said at least one of a plate or pole thereby defining a liquid surface therewithin;   directing a source of electromagnetic radiation into said container and through said liquid surface; and   detecting variations in the intensity of substantially only the radiation having passed at least once through said liquid surface, said variations being caused by changes in the transmissive and refractive properties of said liquid surface upon vibration of said container resulting from earth tremors.   
     
     
       68. A method as in claim 67 wherein: said directing step and said detecting step are performed on the same side of said liquid surface; and   said directing step comprises the steps of reflecting said radiation on the other side of said liquid surface toward the site of said detecting step.   
     
     
       69. A method as in claim 67 wherein said directing step and said detecting step occur on opposite sides of said liquid surface. 
     
     
       70. A method as in claim 69 wherein the area of said liquid surface illuminated by said source is substantially offset from the area of said liquid surface viewed during said detecting step so that as said container vibrates, said surface becomes more turbulent thereby refracting more of the radiation from said source into the view of said detecting step. 
     
     
       71. Method as in claim 67 wherein: said source and detection means are on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incident on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       72. A method as in claim 67 further comprising at least one of the steps of directing radiation from said source to a plurality of locations within said container with a first set of fiber optics, and directing radiation from a plurality of locations within said container to said detecting step with a second set of fiber optics so that said detected variation represents the average change in the transmissive and refractive properties of said liquid surface. 
     
     
       73. A method of detecting misalignment of the wheels of a vehicle comprising the steps of: mounting a container partially filled with liquid thereby defining corresponding fluid levels therewithin one side of each of the front and rear suspension systems of said vehicle;   directing a source of electromagnetic radiation into each of said containers;   detecting variations in the intensity of substantially only the radiation, having passed at least once through said liquid surface, in each of said containers caused by vibrations and/or by accelerations transverse to the axis of said vehicle and resulting from said misalignment; and   comparing said detected variations in said containers on said front and rear suspension systems of said vehicle to detect a misaligned vehicle wheel.   
     
     
       74. A method as in claim 73 wherein said mounting step comprises the steps of affixing a magnet to said containers and attaching said containers to said front and rear suspension systems using said magnet. 
     
     
       75. A method as in claim 73 wherein said comparing step comprises the steps of displaying each of said detected variations in a visually meaningful form. 
     
     
       76. A method as in claim 75 wherein said displaying steps comprise the steps of applying electrical signals representing each of said detected variations respectively to at least one of adjacent ammeters and adjacent voltmeters. 
     
     
       77. A method as in claim 73 wherein said directing and detecting steps in each of said containers are performed on the same side of said liquid surface and said directing step in each of said containers comprises the step of reflecting said radiation from the other side of said liquid surface toward the site of said detecting step. 
     
     
       78. A method as in claim 73 wherein each of said directing and detecting steps occur on opposite sides of said liquid surface. 
     
     
       79. A method as in claim 78 wherein the area of said liquid surface illuminated by said source is substantially offset from the area of said liquid surface viewed during said detecting step so that as said container vibrates, said liquid surface becomes more turbulent, thereby refracting more of the radiation from said source into view of said detecting step. 
     
     
       80. A method as in claim 73 wherein: said source and detection means are on opposite sides of said liquid surface;   the angle of incidence of the light from said source with said liquid surface is not greater than 45°; and   the light incident on the area of the wall of said container opposite said source and on the opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container vibrates, said surface becomes more uneven thereby refracting more of the radiation from said source into said detection means.   
     
     
       81. A method as in claim 73 further comprising at least on the steps of directing radiation from said source to a plurality of locations within said container with a first set of fiber optics, and directing radiation from a plurality of locations within said container towards the site of said detecting step with a second set of fiber optics so that said detected variation represents the average change in the transmissive and refractive properties of said liquid surface. 
     
     
       82. A method of identifying steering malfunctions in a vehicle comprising the steps of: mounting a container partially filled with a liquid thereby defining a liquid surface therewithin on each of the front and rear suspension systems of said vehicle;   directing a source of electromagnetic radiation into each of said containers;   detecting variations in the intensity of radiation in each of said containers along a vertical axis, said variations being caused by changes in the refractive and transmissive properties of said liquid as a result of variations in the acceleration-influenced angle of said liquid surface; and   comparing said detected variations in said containers on the front and rear suspension systems of said vehicle to determine whether the front of said vehicle is accelerating in a direction transverse to the axis of said vehicle at a value different from the rear of said vehicle.   
     
     
       83. A method as in claim 82 wherein said mounting step comprises the steps of affixing a magnet to said containers and attaching said containers to said front and rear suspension systems using said magnet. 
     
     
       84. A method as in claim 82 wherein said comparing step comprises the steps of displaying each of said detected variations in a visually meaningful form. 
     
     
       85. A method of predicting failure of mechanical components of machinery comprising the steps of: mounting a container partially filled with a liquid thereby defining a liquid surface therewithin on said component;   directing a source of electromagnetic radiation into said container and through said liquid surface;   detecting variations in the intensity of substantially only the radiation having passed at least once through said liquid surface being caused by changes in the transmissive and refractive properties of said liquid surface upon vibration of said container; and   comparing the detected variations over time in order to monitor the vibration level indicative of imminent component failure.   
     
     
       86. A method of monitoring metal fatigue in an aircraft support comprising the steps of: mounting a container partially filled with a liquid thereby defining a liquid surface therewithin on the skin of said aircraft near said support;   directing a source of electromagnetic radiation into said container and through said liquid surface;   detecting variations in the intensity of substantially only the radiation having passed at least once through said liquid surface, being caused by changes in the transmissive and refractive properties of said liquid surface upon vibration of said container; and   comparing the detected variations over time to monitor the vibration level of said support and detect an increase in the vibration level indicative of metal fatigue.   
     
     
       87. A method of detecting the intrusion of a subject into a building area comprising the steps of: mounting a container partially filled with liquid thereby defining a liquid surface therewithin on a structural member of said building area;   directing a source of electromagnetic radiation into said container and through said liquid surface;   detecting variations in the intensity of substantially only the radiation having passed at least once through said liquid surface being caused by changes in the transmissive and refractive properties of said liquid surface upon vibration of said container; and   comparing the detected variations over time to monitor the vibration level of said floor and to detect an increase in the vibration level indicative of the presence of said subject.   
     
     
       88. A method of detecting imbalance in the wheels of a vehicle comprising the steps of: mounting a container partially filled with liquid thereby defining corresponding liquid surfaces therewithin on a plurality of suspension systems respectively associated with each of said wheels of said wheels of said vehicle;   directing source of electromagnetic radiation into each of said containers;   detecting variations in the intensity of substantially only the radiation having passed at least once through respective said liquid surfaces in each of said containers being caused by vibrations in said plurality of suspension systems resulting from said imbalance; and   comparing said detected variations from said containers on said plurality of suspension systems in order to determine the imbalanced wheel.   
     
     
       89. An electro-mechanical transducer comprising: a container;   a liquid partially filling said container thereby defining a liquid surface therewithin;   a source of electro-magnetic radiation mounted with respect to said container so as to illuminate at least a portion of said liquid surface;   an electro-magnetic radiation detection means responsive to said source and disposed on the side of said liquid surface opposite said source, the area of said liquid surface illuminated by said source being at least mostly out of the area of said liquid surface viewed by said detection means so that as said container moves, said surface changes orientation, thereby refracting more of the radiation from said source into said detection means.   
     
     
       90. An electro-mechanical transducer comprising: a container;   a liquid partially filling said container thereby defining a liquid surface therewithin;   a source of electro-magnetic radiation disposed entirely on one side of said surface, the angle of incidence of light from said source with said liquid surface being not greater than 45°;   an electro-magnetic radiation detection means responsive to said source, said detection means being disposed entirely on the other side of said liquid surface, the light incident on the area of wall of said container opposite said source and on the opposite side of said liquid surface from said source being at least mostly not incident on said detection means when said liquid surface is substantially quiescent, so that as said container moves, the said surface changes orientation thereby refracting more of the radiation from said source into said detection means.   
     
     
       91. A method of transforming mechanical movement of an object to an electrical signal comprising the steps of: mounting a container partially filled with a liquid on said object thereby defining a liquid surface therewithin;   directing a source of electro-magnetic radiation into said container, said source being positioned on one side of said liquid surface;   detecting variations in the intensity of radiation with detection means, said detection means being disposed on the opposite side of said liquid surface;   the angle of incidence of the light from said source with said liquid surface being not greater than 45°; and   said detection means being disposed in said container so that the light incident on the area of the wall of said container opposite said source and on opposite side of said liquid surface from said source is at least mostly not incident on said detection means when said liquid level is substantially quiescent, so that as said container moves, said surface changes orientation thereby refracting more of the radiation from said source into said detection means.