Sensor platform for use in machines for washing articles

Abstract

A plurality of fluid condition sensors are combined together to provide a sensor cluster that senses turbidity, temperature, conductivity and the movement of a ferromagnetic object. The plurality of sensors are attached to a substrate and encapsulated, by an overmolding process, with a light transmissive and fluid impermeable material. The sensor cluster can be disposed at numerous different locations within a body of fluid and does not require a conduit to direct the fluid to a particular location proximate the sensor. In a preferred embodiment of the present invention, a circuit is provided which monitors the signal strength of first and second light sensitive components to determine turbidity and, in addition, those signal strengths are also used to advantageously determine the most efficient magnitude of current necessary to drive a light source, such as a light emitting diode. By controlling the current to a light emitting diode as a function of the strength of light signal received by first and second light sensitive components, the turbidity sensor can be operated at a more efficient and effect level.

The embodiments of the invention in which an exclusive property or right is claimed are defined as follows: 
     
       1. A liquid condition sensor, comprising: a substrate, said substrate having conductive portions, said substrate being disposed within a pump housing of an appliance;   means, attached to said substrate, for directing a beam of light energy along a first line;   first light sensitive means, attached to said substrate, for receiving light energy directly from said directing means, said first line intersecting said first receiving means, said first receiving means providing a first signal representative of the light intensity impinging on said first receiving means;   second light sensitive means, attached to said substrate, for receiving reflected light from said directing means along a second line, said second line being at an angle to said first line, said second line intersecting said second receiving means, said second receiving means providing a second signal representative of the light intensity impinging on said second receiving means, said directing means, said first receiving means and said second receiving means being connected in electrical communication with said conductive portions of said substrate; means for comparing said first and second signals, said comparing means being connected in signal communication with said first and second receiving means; and   first means, attached to said substrate, for measuring the electrical conductivity of said liquid, said measuring means being connected in electrical communication with a second one of said conductive portions of said substrate, said first measuring means comprises two electrodes extending from said substrate and spaced apart from each other by a predetermined distance.   
     
     
       2. The sensor of claim 1, further comprising: second means, attached to said substrate, for measuring the temperature of said liquid, said second measuring means being connected in electrical communication with a third one of said conductive portions of said substrate.   
     
     
       3. The sensor of claim 1, further comprising: a magnetically sensitive component, attached to said substrate, for detecting the presence of a ferromagnetic object within a predetermined detection zone proximate said substrate, said magnetically sensitive component being connected in electrical communication with a fourth one of said conductive portions of said substrate.   
     
     
       4. The sensor of claim 3, wherein: said magnetically sensitive component comprises a magnetoresistive element.   
     
     
       5. The sensor of claim 1, further comprising: a plurality of electrical conductors extending from said substrate, said plurality of electrical conductors being connected in signal communication with said first, second, third and fourth conductive portions of said substrate.   
     
     
       6. The sensor of claim 1, wherein: said substrate, said light directing means, said first light sensitive means and said second light sensitive means are encapsulated within a light transmissive and liquid impermeable substance.   
     
     
       7. The sensor of claim 6, wherein: said light transmissive and liquid impermeable substance is clear epoxy.   
     
     
       8. The sensor of claim 1, wherein: said substrate, said first electrical conductivity measuring means, said light directing means, said first light sensitive means and said second light sensitive means are encapsulated within a light transmissive and liquid impermeable substance.   
     
     
       9. A liquid condition sensor, comprising: a substrate having a first planar surface, said substrate having a plurality of electrically conductive portions disposed on said first planar surface, said substrate being disposed within a pump housing of a machine for washing articles;   means, attached to said substrate, for directing a beam of light energy along a first line in a direction parallel to said first planar surface;   first light sensitive means, attached to said substrate, for receiving light energy directly from said directing means, said first line intersecting said first receiving means, said first receiving means providing a first signal representative of the light intensity impinging on said first receiving means;   second light sensitive means, attached to said substrate, for receiving reflected light from said directing means along a second line which is parallel to said first planar surface, said second line being perpendicular to said first line, said second line intersecting said second receiving means, said second receiving means providing a second signal representative of the light intensity impinging on said second receiving means, said directing means, said first receiving means and said second receiving means being connected in electrical communication with a first one of said plurality of electrically conductive portions of said substrate;   means for comparing said first and second signals, said comparing means being connected in signal communication with said first and second receiving means; and   first means, attached to said substrate, for measuring the temperature of said liquid proximate said first planar surface, said first measuring means being connected in electrical communication with a third one of said plurality of electrically conductive portions of said substrate.   
     
     
       10. The sensor of claim 9, further comprising: second means, attached to said substrate, for measuring the electrical conductivity of said liquid proximate said first planar surface, said second measuring means being connected in electrical communication with a second one of said plurality of electrically conductive portions of said substrate.   
     
     
       11. The sensor of claim 10, wherein: said second measuring means comprises two electrodes extending from said first planar surface and spaced apart from each other by a predetermined distance.   
     
     
       12. The sensor of claim 11, further comprising: a magnetically sensitive component, attached to said substrate, for detecting the presence of a ferromagnetic object within a predetermined detection zone proximate said substrate, said magnetically sensitive component being connected in electrical communication with a fourth one of said plurality of electrically conductive portions of said substrate.   
     
     
       13. The sensor of claim 12, wherein: said magnetically sensitive component comprises a magnetoresistive element.   
     
     
       14. The sensor of claim 12, further comprising: a plurality of electrical conductors extending from a second planar surface of said substrate, said second planar surface being disposed on an opposite side of said substrate from said first planar surface, said plurality of electrical conductors being connected in signal communication with said first, second, third and fourth electrically conductive portions of said substrate. .[.   
     
     
       15.  A liquid condition sensor, comprising: a substrate, said substrate having conductive portions, said substrate being disposed within a pump housing of an appliance;   means, attached to said substrate, for directing a beam of light energy along a first line;   first light sensitive means, attached to said substrate, for receiving light energy directly from said directing means, said first line intersecting said first receiving means, said first receiving means providing a first signal representative of the light intensity impinging on said first receiving means;   second light sensitive means, attached to said substrate, for receiving reflected light from said directing means along a second line, said second line being at an angle to said first line, said second line intersecting said second receiving means, said second receiving means providing a second signal representative of the light intensity impinging on said second receiving means, said directing means, said first receiving means and said second receiving means being connected in electrical communication with said conductive portions of said substrate; and   means for comparing said first and second signals, said comparing means being connected in signal communication with said first and second receiving means..]..[.16. The sensor of claim 15, further comprising:   a magnetically sensitive component, attached to said substrate, for detecting the presence of a ferromagnetic object within a predetermined detection zone proximate said substrate, said magnetically sensitive component being connected in electrical communication with said conductive   
     
     
        portions of said substrate..]..Iadd.17.  A liquid condition sensor, comprising: a substrate, said substrate having conductive portions, said substrate being disposed within a pump housing of an appliance;   means, attached to said substrate, for directing a beam of light energy along a first line;   first light sensitive means, attached to said substrate, for receiving light energy from said directing means, said first receiving means providing a first signal representative of the light intensity impinging on said first receiving means; and   means for determining said liquid condition, said determining means being connected in electrical communication with said first light sensitive means. .Iaddend..Iadd.18. The sensor of claim 17 further comprising:   a magnetically sensitive component, attached to said substrate, for detecting the presence of a ferromagnetic object within a predetermined detection zone proximate said substrate, said magnetically sensitive component being connected in electrical communication with said conductive portions of said substrate. .Iaddend..Iadd.19. The sensor of claim 17, further comprising:   second light sensitive means, attached to said substrate, for receiving light from said directing means, said second receiving means providing a second signal representative of the light intensity impinging on said second receiving means, said directing means, said first receiving means and said second receiving means being connected in electrical communication with said conductive portions of said substrate; and   means for comparing said first and second signals, said comparing means being connected in signal communication with said first and second receiving means. .Iaddend.