Automatic window wiper control

Abstract

The invention is directed to an automatic wiper control circuit for operating window wipers automatically when moisture is sensed. The control circuit additionally provides for increasing the speed of a dual speed wiper motor when a high level of moisture is detected. The system comprises a moisture sensor which senses moisture thereon. A circuit associated with the moisture sensor converts the moisture level to DC voltage. At a preselected level of this DC voltage the wiper motor operates in one of its two different speeds. A lack of a predetermined amount of moisture terminates the wiper motor operation. If the control circuit terminates the wiper motor action during wiper sweep, the normal homing circuit of the wiper motor continues to operate the motor until the wiper blade or blades reach the wiper blade home position. Sequential illumination of a plurality of light emitting diodes (LEDS) occur during a wiping cycle when the circuit is operating normally. A switch is provided to remove the automatic wiper control circuit from the conventional automotive wiper motor circuit. A separate LED provides a visual indication of automatic wiper control circuit disconnection from the conventional automotive wiper motor circuit.

What is claimed is: 
     
       1. An automatic wiper motor control system for operating a window wiper motor which operates at least one wiper blade to and fro across window for removing moisture from .[.the.]. .Iadd.an .Iaddend.area which it sweeps, said motor having a park circuit means for returning said wiper blade to a home location when said wiper motor .[.motor.]. .Iadd.operation .Iaddend.is terminated at other than the wiper blade home location comprising: a voltage source;   a moisture sensor, said moisture sensor comprising a plurality of spaced apart exposed conductive strips positioned within .[.an.]. .Iadd.the .Iaddend.area of the sweep of said at least one wiper blade;   a voltage storage means;   a scanning circuit for sequentially connecting adjacent pairs of said conductive strips, one of said pair to said voltage source and the other of said pair to said voltage storage means;   a wiper motor operating circuit .Iadd.for activating said wiper motor.Iaddend.;   a voltage sensing means connected between said voltage storage means and said wiper motor operating circuit, said voltage sensing means activates said wiper motor operating circuit when the voltage level of said voltage storage means exceeds a preselected voltage level; and   a wiper position sensor means positioned along the sweep of said wiper blade and influenced by the blade passing thereacross for .[.activating the operation of said voltage sensing means.]. .Iadd.controlling termination of the operation of said wiper motor .Iaddend., whereby a determination is made by said .[.automotive.]. .Iadd.automatic .Iaddend.wiper motor control system to operate said wiper motor or terminate said operation .Iadd.in dependence upon the amount of moisture on the window .Iaddend..   
     
     
       2. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 1 wherein said wiper motor is multi-speed. 
     
     
       3. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 1 wherein said voltage source is a storage battery. 
     
     
       4. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 1 wherein said scanning circuit comprises a pair of multiplexer circuits each of which is operated at a common frequency. 
     
     
       5. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 1 wherein said voltage sensing means comprises a means to constantly remove a portion of the voltage stored .[.therein.]. .Iadd.in said voltage storage means.Iaddend.. 
     
     
       6. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 2 wherein said voltage sensing means comprises means for operating said multi-speed wiper motor at one speed when the voltage in said voltage storage means is above a first preset level and at an increased speed when the voltage in said voltage storage means exceeds a second preset level. 
     
     
       7. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 6 wherein the first preset level of voltage which operates said multi-speed wiper motor at said one speed is adjustable. 
     
     
       8. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 6 wherein the second preset level of voltage which operates said multi-speed wiper motor at said increased speed is adjustable. 
     
     
       9. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 1 additionally comprising visual means for providing indication of operation of said scanning circuit. 
     
     
       10. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 9 wherein said visual means includes a plurality of .[.LEDS.]. .Iadd.LEDs.Iaddend.. 
     
     
       11. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 10 wherein said .[.LEDS.]. .Iadd.LEDs .Iaddend.all illuminate in the same color. 
     
     
       12. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 10 wherein some of said .[.LEDS.]. .Iadd.LEDs .Iaddend.illuminate in different colors than others thereof. 
     
     
       13. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 2 additionally comprises a switch for removing said automatic wiper motor control system from control of said multi speed wiper motor and an LED connected in conjunction therewith for a visual indication of the removal of said automatic wiper motor control system from control of said multi-speed wiper motor. 
     
     
       14. The .[.invention.]. .Iadd.system .Iaddend.as defined in claim 1 wherein said park circuit means continues to operate said wiper motor when said wiper blade across said position sensor .Iadd.means .Iaddend.causes said automatic wiper motor control .Iadd.system .Iaddend.to terminate operation of said wiper motor. .Iadd. 
     
     
       15.  An automatic wiper control system for operating a window wiper motor which moves at least one wiper blade to and fro across the window for removing moisture from an area which it sweeps, said system comprising, in combination: (a) a voltage source;   (b) current detection means, having an input and an output, for producing a wiper activation signal at said output, said wiper motor being operated in response to said wiper activation signal;   (c) a moisture sensor comprising at least three spaced apart, exposed conductive strips;   (d) first means for connecting one of said conductive strips to said voltage source; and   (e) second means for connecting one other of said conductive strips to said current detection means;   wherein said first and second means sequentially scan adjacent pairs of said conductive strips, one of said pair to said voltage source and the other of said pair to said current detection means, respectively; and   wherein said current detection means includes means for accumulating a parameter substantially representative of the current received by each of said other conductive strips during at least one scan of said conductive strips by said first and second means;   whereby a determination is made by said wiper motor control system to operate said wiper motor or to terminate its operation, in dependence upon the amount of moisture on the window. .Iaddend. .Iadd.   
     
     
       16.  The control system defined in claim 15, wherein said moisture sensor is positioned on the window within the area of sweep of said wiper blade. .Iaddend. .Iadd. 
     
     
       17.  The control system defined in claim 15, wherein said current detection means includes: voltage storage means; and   voltage sensing means, connected to said voltage storage means, for producing said wiper activation signal when the voltage level of said voltage storage means exceeds a preselected voltage level. .Iaddend. .Iadd.18. The control system defined in claim 15, further comprising wiper position sensor means positioned along the sweep of said wiper blade and influenced by the blade passing thereacross, for enabling the operation of said current detection means to produce said wiper activation signal. .Iaddend. .Iadd.19. The control system defined in claim 15, wherein said wiper motor is multi-speed and wherein said current detection means is operative to control the speed of said motor in response to the level of current at said input. .Iaddend. .Iadd.20. The control system as defined in claim 15, wherein said voltage source is a storage battery. .Iaddend.   
     
     
        .Iadd.21.  The control system defined in claim 15, wherein said first and second means comprise a pair of multiplexer circuits each of which is operated at a common frequency. .Iaddend. .Iadd.22. The control system defined in claim 17, wherein said voltage sensing means comprises a means to constantly remove a portion of the voltage stored in said voltage storage means. .Iaddend. .Iadd.23. The control system defined in claim 17, wherein said wiper motor is multi-speed and wherein said voltage sensing means comprises means for operating said multi-speed wiper motor at one speed when the voltage in said voltage storage means is above a first preset level and at an increased speed when the voltage in said voltage storage means exceeds a second preset level. .Iaddend. .Iadd.24. The control system defined in claim 23, wherein the first preset level of voltage which operates said multi-speed wiper motor at said one speed is adjustable. .Iaddend. .Iadd.25. The control system defined in claim 23, wherein the second preset level of voltage which operates said multi-speed 
     
     
        wiper motor at said increased speed is adjustable. .Iaddend. .Iadd.26. The control system defined in claim 15, additionally comprising visual means for providing indication of operation at least one of said first and second means and said current detection means. .Iaddend. .Iadd.27. The control system defined in claim 26, wherein said visual means includes a plurality of LEDs. .Iaddend. .Iadd.28. The control system defined in claim 27, wherein said LEDs all illuminate in the same color. .Iaddend. .Iadd.29. The control system defined in claim 27, wherein some of said LEDs illuminate in different colors than others thereof. .Iaddend. .Iadd.30. The control system defined in claim 19, further comprising a manual switch for removing said automatic wiper motor control system from control of said multi-speed wiper motor. .Iaddend. .Iadd.31. The control system defined in claim 30, further comprising an LED connected with said manual switch for a visual indication of the removal of said automatic wiper motor control system from control of said multi-speed wiper motor. 
     
     
        .Iaddend. .Iadd.32.  The control system defined in claim 18, wherein said wiper motor has park circuit means for returning said wiper blade to a home location when said wiper motor operation is terminated at other than the wiper blade home location, said park circuit means continuing to operate said wiper motor when said wiper blade crosses said position sensor means and causes said automatic wiper motor control system to terminate operation of said wiper motor. .Iaddend.