Abstract: A system for sensing loads in a washing machine by measuring angular acceleration is provided. The washing machine includes a washer basket and an agitator that can be angularly accelerated about a spin axis during a predetermined dry spin cycle. The system includes a magnetic source, such as a permanent magnet, positioned in the agitator for producing a predetermined magnetic field. A magnetic sensor, made-up of inductive coils or solid state sensors, is positioned to be electromagnetically coupled to the magnetic source for supplying an output signal that varies in a predetermined manner as the agitator is angularly accelerated relative to the magnetic sensor. A signal processor is coupled to the magnetic sensor for receiving the output signal supplied by the magnetic sensor.

Abstract: A dynamic temperature compensation method for a turbidity sensor in an appliance for washing articles is provided. The method includes the steps of: retaining substantially particle-free liquid upon completion of cleansing operations in the appliance, reading initial values of temperature and turbidity of the liquid, measuring additional values of temperature and turbidity of the liquid at predetermined time intervals, and calculating a temperature coefficient, based upon respective ones of the initial and the additional values of temperature and turbidity, for characterizing a temperature response of the turbidity sensor over a predetermined temperature range.

Abstract: An alternating current sensor includes a conductive pipe and a cylindrical-shaped conductive element preferably partially surrounded by the pipe. The pipe is substantially concentric to the conductive element and a conductor electrically connects a pair of corresponding ends of the pipe and conductive element to form a connected conductive path through the sensor. The pipe and the conductive element are spaced apart a predetermined radial distance to form a magnetic field in the space between the pipe and the conductive element during current flow along the connected conductive path. A flux sensor, such as an air-core coil, senses changes in magnetic flux over a sense region situated in the space between the pipe and the conductive element. A transformer having a saturable magnetic core is responsive to a magnetic field over a transformer region for generating a predetermined level of electrical current which can be used for safely powering various electrical circuits associated with the current sensor.

Abstract: A system for sensing loads in a washing machine is provided. The washing machine includes a tub inside a cabinet. The tub encloses a washer basket and an agitator. The washing machine further includes a motor for rotating the basket and the agitator about a spin axis, and a suspension system for supporting the washer basket so that the washer basket travels along a travel axis based on the load in the washer basket. The system includes a magnetic source attached to a lateral section of the washer basket for producing a magnetic field. A sensor is attached to a predetermined lateral wall of the cabinet. The sensor is made up of first and second magnetic sensing elements situated to have a predetermined spacing between one another substantially along the travel axis. The first and second magnetic sensing elements are electromagnetically coupled to the magnetic source for supplying, respectively, first and second output signals as the washer basket rotates relative to the magnetic sensor.

Abstract: A temperature compensation method for a turbidity sensor in an appliance for washing articles is provided. The method includes the steps of: measuring temperature and turbidity of a liquid, such as water, for washing the articles, calculating a turbidity value corresponding to a predetermined reference temperature; and adjusting the measured turbidity of the liquid with respect to the calculated turbidity value so as to provide a temperature compensated turbidity measurement. The method can further include the step of measuring temperature and turbidity of substantially particle-free liquid. This allows for calculating a normalized turbidity value which is substantially free or independent from temperature variation effects.

Abstract: A current sensor for measuring a primary electrical current inducing a primary magnetic field defined over a known region includes a first sensor unit for measuring the line integral of the primary magnetic field along a first predetermined path included within the known region; and a second sensor unit for measuring the line integral of the primary magnetic field along a second predetermined path within the known region, the line integral of the primary magnetic field measured by the second sensor unit being a predetermined calibrated amount different from the line integral of the primary magnetic field measured by the first sensor unit. The current sensor further includes a current source for generating a current inducing a magnetic field to partially offset the difference between the line integral of the primary magnetic field measured by the first sensor unit and the line integral of the primary magnetic field measured by the second sensor unit.

Abstract: A Mach number sensor comprises a first pulse speed sensor situated in direct contact with an open area through which a first pressure pulse can pass and a second pulse speed sensor situated in a thermally conductive tube with membrane-covered ends having stationary air through which a second pressure pulse can pass. Each of the first and second pulse speed sensors may comprise two total internal reflection detectors and a timer for determining elapsed time for passage of the pressure pulse between the two detectors.

Abstract: An electro-optics current sensing system for sensing and avoiding thermally induced measurement errors in a current sensor includes a beam generator, such as a light emitting diode or a laser diode, thermally coupled to the current sensor for encoding into the optical beam supplied by the beam generator both temperature and sensed current information. An electro-optics (E/O) demodulator which includes a wavelength division multiplexer (WDM) demodulates the encoded optical beam to recover the temperature and sensed current information from a pair of demodulated signals which can be further processed for filtering resistivity changes from the sensed current measurement.

Abstract: An alternating current sensor for measuring a primary alternating current inducing a magnetic flux density defined over a known region comprises: a first sensor for measuring changes in magnetic flux due to the primary current over a first predetermined area included within the known region; a second sensor for measuring changes in magnetic flux due to the primary current over a second predetermined area within the known region, the changes in magnetic flux measured by the second sensor being a predetermined amount different from the changes in magnetic flux measured by the first sensor; and a current source for generating a current inducing changes in magnetic flux over a third predetermined area to offset the difference between the changes in magnetic flux measured by the first sensor and the changes in magnetic flux measured by the second sensor.

Abstract: An alternating current sensor employing a mutually-inductive current sensing scheme comprises a conductive pipe and a cylindrical-shaped conductive element at least partially surrounded by the pipe. The pipe is substantially concentric to the conductive element and a conductor electrically connects a pair of corresponding ends of the pipe and conductive element to form a connected conductive path through the sensor. The conductive element may include a passage or opening shaped to form a magnetic field within the passage during current flow along the conductive path.

Abstract: A noninductive shunt current sensor includes a cylindrical-shaped conductive element and a concentric conductive pipe electrically connected at one end by a conductor, such as a washer. Except for the conductor, the pipe and conductive element are electrically isolated from each other by insulation, such as a polyimide or an air-gap. Sensing wires are electrically connected to contact points, each contact point being located on either the inner surface of the inner pipe or the outer surface of the outer pipe. The wires pass through a space where the magnetic field is substantially null, thereby minimizing any mutual coupling effects. A magnetic core and a coil can be situated between the pipe and the conductive element to provide an electrical self-power capability to the noninductive shunt current sensor.

Abstract: A current sensor for measuring a primary electrical current inducing a magnetic flux density defined over a known region comprises: a first sensor for measuring magnetic flux due to the primary current over a first predetermined area included within the known region; and a second sensor for measuring magnetic flux due to the primary current over a second predetermined area within the known region, the magnetic flux due to the primary current measured by the second sensor being a substantially predetermined calibrated amount different from the magnetic flux due to the primary current measured by the first sensor. The current sensor may further include a current source for generating a current inducing a magnetic flux density within the known region to at least partially offset the difference between the magnetic flux due to the primary current measured by the first sensor and the magnetic flux due to the primary current measured by the second sensor.

Abstract: A noninductive shunt current sensor includes a cylindrical-shaped conductive element and a concentric conductive pipe electrically connected at one end by a conductor, such as a washer. Except for the conductor, the pipe and conductive element are electrically isolated from each other by insulation, such as Kapton.TM. or an air-gap. Sensing wires are electrically connected to contact points, each contact point being located on either the inner surface of the inner pipe or the outer surface of the outer pipe. The wires pass through a space where the magnetic field is substantially null, thereby reducing any mutual coupling effects.

Abstract: An alternating current sensor employing a mutually-inductive current sensing scheme comprises a conductive pipe and a cylindrical-shaped conductive element at least partially surrounded by the pipe. The pipe is substantially concentric to the conductive element and a conductor electrically connects a pair of corresponding ends of the pipe and conductive element to form a connected conductive path through the sensor. The pipe and the conductive element are spaced apart a predetermined radial distance to form a magnetic field in the space between the pipe and conductive element during current flow along the conductive path.

Abstract: An optical temperature compensation system for spectral modulation sensors includes a light director for receiving excitation light, a spectral modulation sensor for receiving and modulating a first portion of the excitation light from the light director, and an optical processing component for receiving and determining properties of a second portion of the excitation light from the light director and the modulated first portion of the excitation light. The optical processing component comprises a dispersive element for dispersing the second portion of the excitation light and the modulated first portion of the excitation light and a charge transfer device for converting the dispersed portions of light into electrical signals. A digital signal processor calculates a detected ratio of the electrical signals which compensates for inaccuracies in measurement due to source temperature variations.

Abstract: An optical temperature compensation system for spectral modulation sensors comprises a light director for receiving excitation light and a spectral modulation sensor for receiving a first portion of the excitation light from the light director. A source monitoring component is positioned for receiving a second portion of the excitation light from the light director. The source monitoring component includes offset optics optically coupled to the light director, a source dichroic filter for splitting the light from the offset optics, a first source photodetector for receiving wavelengths above the effective cutoff wavelength of the source dichroic filter, and a second source photodetector for receiving wavelengths below the effective cutoff wavelength of the source dichroic filter.

Abstract: An apparatus for detecting presence of a measurand includes a measurand sensitive layer overlying a fiber field access block. The fiber field access block has a clad fiber positioned such that a portion of the fiber is exposed to the measurand sensitive layer and any cladding on that portion of the fiber is thinner than required to prevent an evanescent wave from escaping the fiber. An optical source and an optical detection component are coupled to the fiber. Changes in the measurand sensitive layer, which are caused by interaction with the measurand, alter the phase velocity matching conditions of the fiber and measurand sensitive layer and can be measured by evaluating shifts in the output signals resulting from presence of the measurand.

Abstract: An apparatus for detecting a measurand includes a fiber field access block having a clad fiber positioned in the fiber field access block such that a portion of the fiber is exposed to an outer surface and any cladding on that portion of the clad fiber is thinner than required to prevent an evanescent wave from escaping the clad fiber. A measurand sensitive layer is provided over the outer surface. A grating is present in either the measurand sensitive layer or the fiber. An optical source and an optical detection component are coupled to the clad fiber. The optical detection component measures shifts in output signals resulting from presence of the measurand in the environment of the fiber field access block caused by changing Bragg conditions which result from swelling of the measurand sensitive layer. The concentration of the measurand can be determined from the detected shifts.

Abstract: Apparatus for sensing linear displacement of an object between first and second locations along an axis is used to sense conditions that can be made to vary displacement of an object in accordance with the condition, such as temperature, pressure and rotary motion. A light beam projected along an incident light path to the object is reflected along a reflective light path by a reflector affixed to the object. A photo-sensor array in the reflective light path intercepts the reflected light beam and produces samples of the intensity of the reflected image at multiple positions along a line across the array. An imager coupled to the array converts the light samples to representative electrical samples.