Abstract: A sensor arrangement for detecting a wetting, in particular a precipitation and dirt accumulation, on a window (13) is proposed, with at least one transmitter (14) and at least one receiver (15) for the transmitter light (17) emitted by the transmitters (14), where the transmitters (14) and receivers (15) are disposed on the vertex points of an imaginary trapezoid. As a result, the external dimensions of the sensor are reduced, the ratio of sensitive area (19) and base area (18) of the sensor is improved, and a coherent sensitive area is produced, where there is also space available for a receiving element of an automatic light control.

Abstract: A windscreen wiper device and a method for wiping windscreens, including at least one motor whose direction of rotation can be altered, at least one wiper which is coupled to the motor and which moves back and forth between two reversing positions, a control device which switches the motor by means of switching signals and operating signals which are conveyed to the control device. The control device determines the switching signals from the operating signals to determine the reversing positions of the wiper. The degree of wetness of the windscreen surface is conveyed to the control mechanism and used as an operating signal.

Abstract: Operation of a windshield wiper system for cleaning a windshield of a motor vehicle includes driving at least one wiper by an electric drive motor so that the at least one wiper shifted between two terminal positions, processing by a control unit as the input variable the output signals of a rain quantity and the switching signals of a manually controllable switch mechanism, and processing as the output variable a supply voltage of the electric drive motor so as to control the wiper speed, operating the at least one wiper (8) with variable intermittent interval times and at variable wiper speeds, as a function of a rain quantity detected by the rain sensor (12), so that the precisely one wiper speed and precisely one intermittent interval time are associated with each measured rain quantity, and moving the at least one wiper (8) in an intermittent mode with a lower speed than in a continuous mode.

Abstract: A housing for a TV camera has an automatic wiping mode for automatically driving a wiper, which is provided at a front window of the housing, at predetermined time intervals. The execution of the automatic wiping mode while the TV camera is unused prevents a large amount of snow and frost, etc. from adhering to the front window. The wiper and two nozzles of a window-washing device for jetting a washing liquid are provided on the front window of the housing in a pan/tilt head. If the pan/tilt head is set to the automatic wiping mode, the wiper and the window-washing device automatically operate at predetermined time intervals. This prevents the snow and the frost from adhering to the front window while the pan/tilt head is not operated, e.g., at night. Thus, the shooting can be begun quickly when the need arises.

Abstract: A control device for the drive motor of a windscreen wiper device in a vehicle, especially a motor vehicle, comprising a control switch which can be activated by means of a manually actuated wiper switch and which automatically controls the drive motor in a switching stage of said wiper switch according to a rain sensor signal corresponding to a characteristic curve. The operating data for the drive motor varies according to the external effects of lighting, temperature, or speed parameters.

Abstract: A window fan assembly comprising a housing with openings therein for an air stream through the housing; at least one fan is mounted in the housing for generating the air stream through the openings of the housing; and a sensor connected to the housing, the sensor being disposed on the housing for detecting moisture particles associated with the air stream, upon the detection of a moisture particle of a predetermined size, the sensor causes an interruption of the air stream by stopping the fan operation.

Abstract: A method and a device for controlling a wiper motor (30) of a motor vehicle are described. A rain sensor (32) sends signals (S) to a control device and the wiper motor (30) is switched off when a first threshold (S1) is exceeded or is not reached. After a defined time period (T1) after switching off the wiper motor (30), the wiper motor (30) is switched on in order to remove residual wetness when the signals (S) exceed or drop below a lower, second threshold (S2).

Abstract: A raindrop sensor detects an amount of raindrops landed on a window glass and outputs a measurement signal to a microcomputer. The microcomputer calculates an average amount of raindrops by averaging a predetermined number of the latest measurements. The microcomputer calculates an interval time for the wiper based on the calculated average amount of raindrops. At this time, when the calculated average amount of raindrops deviates from a predetermined reference value, the microcomputer calculates the average amount of raindrops using a smaller number of the latest measurements.

Abstract: A detector of stains on a transparent plate surface is arranged on an internal surface of the plate and includes an emitter for emitting a modulated light signal towards the inside of the plate and a receiver for receiving the signal after it has been reflected on an external surface of the plate. An optical unit made with a material having an index substantially higher than the plate, is arranged on the internal surface of the plate. The optical unit is made up of at least three faces returning the light signal and an interface with the internal surface of the plate through an optical coupler. A deflector deflects the signal from the emitter toward the plate and from the optical unit towards the receiver. At least two reflections on the external surface of the plate are produced through the optical coupler without reflection on the internal surface of the plate.

Abstract: Two embodiments include a first image sensor (14, 114) for sensing a first image of the exterior surface of the glass (12) along a first optical axis A and a second image sensor (16, 116) for sensing a second image of the exterior surface of the glass (12) along a second optical axis B which intersects the first optical axis A at an intersection X disposed adjacent the exterior surface of the glass (12). Both embodiments include an image correlator (22) for correlating the first and second images and producing an activation signal (24) in response to coincidence of moisture (10) in the respective correlated first and second images. The rain sensor accurately interprets images of moisture that lie in a narrow measurement zone adjacent the exterior surface of the windshield while disregarding images of objects that lie outside that zone.

Abstract: An object sensor and object sensing method that sense the status of the sensing surface by detecting a dynamic impact of a rain drop, not by comparing the signal with a reference value. An object sensor sensing the status of a sensing surface by detecting a light with a photo detector, which light has been emitted by a photo emission element and reflected on the sensing surface, comprises: a means for generating a time lag signal from the output signal of the photo detector; a means for calculating a differential signal between the output signal of the photo detector and the time lag signal; and a means for judging the status of the sensing surface by detecting the generation of the differential signal.

Abstract: An automatic attachable side-view mirror cleaning device is provided for cleaning the side-view mirrors on tractor-trailer rigs. Utilizing a rubber squeegee blade, similar to that used on windshield wipers, the blade travels up and down the long, thin mirror of a tractor-trailer rig. The squeegee scraper blade utilizes two vertical tracks which reside on the two exterior sides of the mirror and is powered by a small electric motor located under the dashboard. Additionally, washer solvent is directed at the mirror using a small pump, through jets at the top of the mirror. The solvent system would be tapped into the main solvent system of the truck using small diameter plastic tubing. The controls for both the electric drive motor and the solvent pump would be located in a dash-mounted panel inside the cab. The invention would be made available as a factory option on new trucks as well as be made available as an after-market attachment accessory for do-it-yourself installation.

Abstract: A sensor device is described for detecting wetting of a windshield that has only one transmitter with which two measuring zones of the sensor device can be implemented on a wettable outside of the windshield. A light guidance body injecting transmitter radiation into the windshield has structures with which the transmitter radiation emitted by the transmitter is collected and parallelized in two different directions.

Abstract: A window actuation assembly for a vehicle which is structured to automatically lower at least one, but preferably all of the windows of a vehicle in the event that a vehicle becomes partially or totally submerged in a body of water and regardless if the orientation of the vehicle, is up-right, inverted, on its side, etc. One or more fluid sensors are located strategically throughout the various portions of the vehicle and are specifically structured activate a drive assembly for the lowering of the windows upon sensing a predetermined amount of water within an associated proximity of the vehicle, to the extent that the one or more sensors are themselves at least partially submerged. The sensors are further structured not to be activated in the unlikely event that liquid inadvertently is spilled upon or otherwise applied thereto.

Abstract: A method of operation of a windshield wiper assembly is disclosed for improving the useful life of the wiper blade. The wiper blade acquires a bias, or set, as a consequence of parking and leaving the wiper assembly at the terminus of an inbound stroke. A short activation of the wiper assembly motor in the outbound direction suffices to flip the blade over so that it is biased in the opposite direction. The parked wiper assembly preferably is “flipped” at the conclusion of every other use of the wiper assembly.

Abstract: Moisture detection permits moisture removal equipment, such as automotive windshield wipers and defogger systems, to be operated automatically. A system for detecting moisture on a surface includes a light emitter directed at the surface. The presence of moisture is based on the intensity of light from the emitter reflected by the surface and received by a light sensor. The light sensor accumulates charge in response to incident light over a variable integration period.

Abstract: A sensor device is described for detecting wetting, in particular rainfall and soiling, on a windshield that has at least two, preferably eight, transmitters and at least one receiver for receiving light emitted by the respective transmitters. The at least two transmitters are arranged concentrically around the at least one receiver. A base area is defined by the at least two transmitters and the at least one receiver, with the base area being at least a sector of a circle. This reduces an outer dimension of the sensor device and improves a ratio of sensitive area to base area of the sensor device.

Abstract: A moisture sensor for detecting moisture on the surface of a transparent material. The moisture sensor includes one or more emitters for producing emitter signals, and one or more detectors for receiving the emitter signals. The detector produces a detector output signal which is filtered and amplified in a pre-demodulation gain and filtering circuit to remove some of the unwanted signal components including noise from ambient light and EMI. Digital Signal Processing filtering is used after the moisture signal is demodulated to a dc signal to discern small signal changes due to moisture events in the presence of large amounts of the noise created by the pre-demodulation gain circuit. The DSP filtering includes a low pass filter stage and a bandpass filter stage implemented by a microcomputer and provides a Finite Impulse Response, an Infinite Impulse Response, or uses Fast Fourier Transform to provide the necessary filtering.

Abstract: A sensor device is described for detecting wetting, in particular rainfall and soiling, on a windshield that has at least one transmitter and at least one receiver for the light emitted by the transmitters where transmitters and receivers are arranged at the corner points of an imaginary triangle or parallelogram. As a result, the outside dimensions of the sensor are reduced, and the ratio of sensitive area to base area of the sensor is improved.

Abstract: A control device for the driving motor (10) of a windshield system. A manually operated wiper switch (18) is provided for selecting an operating mode, in at least one of which the wiper speed is automatically controlled by a characteristic curve and the signal from a rain sensor (13). To modify the characteristic curve based on the use of the system by an individual driver, the manually operated wiper switch (18) conveys control commands to an adaptation algorithm control in a control circuit (16). The control circuit (16), in response to switching out of the automatic mode, generates a new characteristic curve at a modified operating point, with the new characteristic curve incorporating the modified operating point. When the switching stage which is dependent on the quantity of rain is again activated, the diving motor (11) is controlled according to the new characteristic curve.

Abstract: The invention relates to a method and device for detecting and localizing diffuse-reflecting coatings situated on a translucent pane. The aim of the invention is to make it possible to detect any diffuse-reflecting coatings in a non-contacting manner and to differentiate between coatings situated on the pane surface facing the sensor and those situated on the pane surface facing away from the sensor. To this end an image of an object is captured by a recording unit forming part of the device by positioning the pane in the optical path between the object and recording unit, after which the image information obtained is evaluated accordingly.

Abstract: A rain sensor including light emitting means 7 for guiding light into a window glass so as to undergo total internal reflection within the window glass, light receiving means 8 for receiving the light which has undergone total internal reflection within the window glass, and means for detecting the amount of water drops adhered to or present upon the window glass so as to output a driving signal to a wiper driver apparatus 20, a difference signal corresponding to a difference between a preset reference value and an output signal of an amplifier circuit 17 of the light receiving means is fed back to the amplifier 17, and an amplification factor of the amplifier circuit 17 is adjusted so as to maintain the output signal thereof at a constant value irrespective of the operation condition of the wiper, when electrical power is applied to the rain sensor 2.

Abstract: An apparatus and a method for detecting moisture, such as rain on a vehicle, wherein a sensor acquires an optical image from a region of interest and produces the data to a microprocessor, the microprocessor processes the acquired optical image and selects an algorithm to evaluate the acquired optical image in order to determine whether sufficient moisture exists on the vehicle to warrant action such as activating windshield wipers.

Abstract: An apparatus invention relates to an apparatus and method for monitoring an interior space which is closed off by a locked and/or manually non-unlockable door, flap, sliding sunroof or the like, for example a passenger compartment or luggage compartment of a motor vehicle, with respect to living entities enclosed therein and the quality of their living environment, having a control circuit and sensor evaluation arrangements connected thereto, which arrangements each interact with at least one sensor, a first sensor evaluation arrangement outputting a first signal to the control circuit if there are living entities in the interior space, and a second sensor evaluation arrangement outputting a second signal to the control circuit if the living environment changes in the direction of life- and/or health-threatening states, at least one actuator connected to the control circuit acting on a motor-actuatable closure of the door, flap, sliding sunroof or the like, which is activated by the control circuit for the pu

Abstract: A device for monitoring the state of a window pane includes an optical emitter which emits a light beam on to the window pane. The device also contains an optical receiver which detects light of the light beam modulated by the window pane and, as a result, generates a received signal. The emitter and the receiver are arranged at a distance from the window pane. An evaluation circuit evaluates the received signal in order to determine the state of the window pane.

Abstract: An electrical connection between a potentiometer, an actuating motor and control electronics for controlling an actuating element has heretofore been composed of electrical cables, so that a large number of contact points were necessary overall, whereby however, each additional contact point increased the risk of a fault and made the assembly process more expensive. In order to reduce the number of contact points, the base substrate of the potentiometer and the contact board of the motor are in the form of an integral board, and at least some of the electrical connections comprise conductor tracks embedded in the substrate. Electrical components, such as a motor inductor for radio interference suppression, may also be mounted on the board.

Abstract: The device for the detection of a wetting of a pane of glass, has an optical rain sensor which detects extraneous light and evaluates it for purposes of day-night detection. The amount of light striking the receiver (14) is integrated in an integration stage (16) and supplied to a comparator stage (20). The total light quantity formed by the light of a transmitter (12) and extraneous light and the extraneous light quantity detected when the transmitter (12) is switched off are measured in separate time intervals (Tg, Tf, Tf′). The time interval (Tf, Tf′) utilized for measurement of the extraneous light quantity is to be extended after a predeterminable number of measurement cycles (M) or after a predeterminable time period and/or the threshold (S2) is to be lowered for day-night detection.

Abstract: In one form, the present invention provides an apparatus for controlling a windshield wiper system of a motor vehicle in combination with the motor vehicle. The motor vehicle has a steering wheel. The apparatus includes a first actuation device coupled to the windshield wiper system. The first actuation device controls continuous operation of the windshield wiper system at a selected speed. The second actuation device is coupled to the windshield wiper system and is operative to temporarily increase the selected speed selected by the first actuation device. The second actuation device includes a button for attachment to the steering wheel.

Abstract: Moisture detection permits moisture removal equipment, such as automotive windshield wipers and defogger systems, to be operated automatically. A system for detecting moisture on a surface includes a light emitter directed at the surface. The presence of moisture is based on the intensity of light from the emitter reflected by the surface and received by a light sensor. The light sensor accumulates charge in response to incident light over a variable integration period.

Abstract: A submergence detection sensor installed in a vehicle, having a control circuit board mounted on the vehicle for controlling the operation of a power window which is opened/closed by an electric motor. A pair of pad-like electrodes are installed on the control circuit board which are electrically conductive upon entry of water to generate a leak current therebetween and a submergence detection circuit is connected to one of the electrodes to receive the leak current and to compare with a threshold value to discriminate whether the vehicle submerges into water. A slot is provided in a gap between the electrodes which penetrates the control circuit board such that water present at the gap is discharged from the control circuit board, thereby enabling to effect submergence detection when the vehicle, in fact, submerges in water, while without making false detections owing to water condensation on the control circuit board or migration occurring therein.

Abstract: A sensing system for the detection and analysis of light and/or rain conditions affecting the vehicle has a mounting which can be installed within the scope of an assembly line production. The sensing system has a light sensor and a light sensor control unit and/or a rain sensor and a rain sensor control unit and a common carrier plate on which the light sensor with the light sensor control unit as well as the rain sensor with the rain sensor control unit can be mounted.

Abstract: An apparatus and a method for operating a rain sensor (10) that outputs a sensor signal (18, 22) as a function of the wetting of a window (11) are proposed, having a controller (16) which as a function of the sensor signal (18, 22) outputs a control signal (28) to the rain sensor (10) for regulating the sensor signal (18, 22); for signal evaluation, the sensor signal (18, 22) and in addition the control signal (28) are used for tripping switching events of a device.

Abstract: An apparatus and a method for operating a rain sensor (10) that outputs a sensor signal (18, 22) as a function of the wetting of a window (11) are proposed, having a controller (16) which as a function of the sensor signal (18, 22) outputs a control signal (28) to the rain sensor (10) for regulating the sensor signal (18, 22); for signal evaluation, the sensor signal (18, 22) and in addition the control signal (28) are used for tripping switching events of a device.

Abstract: Moisture detection permits moisture removal equipment, such as automotive windshield wipers and defogger systems, to be operated automatically. A system for detecting moisture on a surface includes a light emitter directed at the surface. The presence of moisture is based on the intensity of light from the emitter reflected by the surface and received by a light sensor. The light sensor accumulates charge in response to incident light over a variable integration period.

Abstract: A water sensor, such as a rain or dew sensor, includes a light emitting device for producing sensing light to be reflected in a transparent plate such as a windshield glass panel of a vehicle, a light receiving device for receiving the sensing light, and a hologram sheet having at least one hologram for defining a light path of the sensing light between the light emitting device and the light receiving device. The hologram sheet may be attached to the inside surface of a windshield glass panel or interposed between inside and outside glass layers of a laminated glass panel.

Abstract: An automatic control system to automatically adjust the speed of windshield wiper blades. This system includes means effective to generate a signal that measures the amount of liquid on the windshield, means to determine the rate of accumulation of liquid on the windshield, means responsive to this signal to automatically vary the speed of the electric motor driven windshield wiper, and means to incorporate the automatic control system into an existing vehicle wiper control system.

Abstract: A submergence detection power-window apparatus is provided with driving motors for moving electric-power driven opening units to opened and closed states, manual switches for manually opening/closing the electric-power driven opening units, control units for driving the motors into rotation in accordance with operations carried out on the manual switches, a submergence detector for detecting submergence of a car body and generating a submergence detection signal and a fastened/loosened seat-belt detector for detecting fastened/loosened states of a seat belt and generating a loosened-seat-belt detection signal in a loosened state of the seat belt wherein the control units drive the motors into rotation in directions to open the electric-power driven opening units when the manual switches are operated to open the electric-power driven opening units provided that a submergence detection signal is received from the submergence detector and a loosened-seat-belt detection signal is received from the fastened/loosen

Abstract: The power window apparatus has a driver's seat side window operating unit and passenger seat side window operating units that have window open/close motors. Each of the window operating units has a window open switch, a window close switch, motor drive means, and motor drive control means for controlling the motor drive means. At least one of the window operating units has submersion detecting means for outputting a submersion detection signal when the submersion of the automobile is detected. The window operating units have signal transmission terminals that transmit and/or receive the submersion detection signal generated by the submersion detecting means.

Abstract: A power window apparatus capable of opening a window or windows of a submerged automobile by manually operating a driver seat window open switch or a passenger seat window open switch both located on a driver seat window operation unit. The driver seat window operation unit and passenger seat window operation units have each a window close switch, a window open switch, a window open/close motor, and a motor drive controller. The driver seat window operation unit has a submersion detector for generating a submersion detection signal, a motor drive controller incorporating a control driver for opening windows when the driver manually operates corresponding window open switches, and connection lines for connecting normally close contacts of passenger seat window open switches located on the driver seat window operation unit with the normally close contacts of the window open switches located on the passenger seat window operation units.

Abstract: A sensor device for detecting wetting, in particular rainfall and soiling, on a windshield (22) has at least one transmitter (12) and at least one receiver (14) for the light (26) emitted by the transmitters (12), where transmitters (12) and receivers (14) are arranged at the corner points of an imaginary triangle or parallelogram (16). Therefore, the outside dimensions (b, l) of the sensor are reduced, and the ratio of sensitive area (20) to base area (16) of the sensor is improved.

Abstract: An autobalance control circuit for use in a moisture sensor which senses moisture on the surface of a transparent material. The moisture sensor includes detectors for receiving emitter signals which are influenced by moisture on the transparent material. The moisture sensor further includes a pre-demodulation circuit for attenuating unwanted signal components in the detector output signal while amplifying the useful signal components for further processing by a microprocessor. An autobalance circuit is provided for receiving the pre-demodulation circuit signal and providing an autobalance signal to the pre-demodulation circuit input. The autobalance signal at least partially cancels the detector output signal to prevent saturation of the pre-demodulation amplifier when undesirable detector output signal amplitudes are encountered.

Abstract: An automatic intensity control unit for use in a moisture sensor which senses moisture on the surface of a transparent material. The moisture sensor includes one or more emitters for producing an emitter signal which is influenced by moisture on the transparent material, and one or more detectors for receiving the emitter signals. The automatic intensity control unit adjusts the intensity of the emitter signals to accommodate transparent materials having different transmittances. The automatic intensity control unit includes a comparator for comparing the intensity the emitter signals received by the detectors with a predetermined reference signal and a counter communicating with the comparator for producing a counter output.

Abstract: A wiper controller apparatus of the water drop sensitive type comprises: light emitting means 7 for guiding light into a window glass so as to undergo total internal reflection within said window glass; light receiving means 8 for receiving the light which has undergone total internal reflection within said window glass; means for detecting the amount of water drops adhered or present upon an outside surface of said window glass based on an output of said light receiving means, and for driving a wiper thereupon; wherein the apparatus further comprises wiper driving means 18 for driving the wiper again by only one cycle if a time interval from an initiation of said wiper action exceeds a predetermined time. The apparatus further comprises anther wiper driving means 18 for driving said wiper when the signal duration time of the output signal S1 of said light receiving means 8 is equal to or greater than a predetermined time.

Abstract: A water drop detection device for detecting an amount of water drops present upon a surface of a transparent substrate in which a light source with a driver circuit guides light into the substrate so as to cause the light to under go internal reflection within the substrate. The light source has a light emitting element and a receiving light sensing element for detecting the light output from the emitting element. The light output from the light emitting element is modulated by a predetermined frequency. A signal corresponding to the modulated component is separated from the output signal of the receiving light sensing element. The output light emission of the light emitting element is maintained at a desired value by feeding the separated signal back to the driver circuit of the light emitting element.

Abstract: A windshield washer control system for use on a vehicle is herein disclosed. The windshield washer control system for use on a vehicle having an occupant compartment with a windshield and a windshield wiper device. The wiper device is movable across a predetermined area of the windshield and the windshield washer device includes a sprayer and a sprayer nozzle. The windshield washer device is comprised of a windshield transparency detection system and a controller unit. The controller unit includes three operating modes. The first operating mode is defined by the windshield washer device being manually operable. The second operating mode is defined by the windshield washer device operating by cycle, wherein the windshield washer device is controlled to spray after a predetermined number of wiper cycles. The third operating mode is defined by the windshield washer device being automatically operable by using the windshield transparency detection system.

Abstract: An optical sensor for detecting wetting of a surface in a motor vehicle, the optical sensor has a measuring segment which has at least one transmitter of electromagnet waves and at least one receiver of electromagnetic waves and in which a windshield is disposable so that when a layer of moisture forms on the windshield upon wetting from precipitation a wave propagation between the at least one transmitter and the at least one receiver changes and an output signal generated by the receiver changes, a housing disposable on an inside of the windshield and having a bottom face adapted to be in physical contact with the windshield, the bottom face of the housing being oval.

Abstract: The device for controlling automatic operation of a windshield wiper in a motor vehicle includes a central electronic control unit provided with means for triggering wiping operations of the windshield wiper; a rain sensor including a detector for rain on the windshield and a device for generating sensor signals for the triggering of individual wiping operations according to detector response, which is connected to the control unit in order to furnish the sensor signals to the control unit, and a sensitivity control device for adjusting rain sensor sensitivity, which includes a display device for observing the rain sensor sensitivity or parameters controlling it optically and buttons operable to adjust the rain sensor sensitivity or at least one of the parameters controlling it.

Abstract: A power window apparatus for a vehicle capable of switching an operation mode of a window to a submersion mode when a submersion of the vehicle is detected, includes a circuit board for controlling the window, a sensor having a pair of electrodes for detecting a continuity between the electrodes when the electrodes are submerged, a housing for accommodating the circuit board and the sensor, a first chamber provided in the housing and enclosed by walls for accommodating the circuit board, a second chamber provided in the housing and enclosed by walls for accommodating the sensor, and an opening provided at the walls of the second chamber for allowing to introduce water into the second chamber so as to merge the sensor in water before the circuit board is submerged.

Abstract: A system and a method for controlling the operation of a vehicle window wiper device as a function of the quantity of liquid present on the window are described. The wiper device comprises an electric drive motor connected to at least one wiper blade arm provided with a wiper blade. The control system comprises: a first sensor adapted to provide a first output signal corresponding to a first quantity dependent on the instantaneous friction between the wiper blade and the vehicle window; a second sensor adapted to provide a second output signal corresponding to a second quantity correlated to the aerodynamic load acting on the wiper blade; and a processing and control unit coupled to both sensors to receive at its input the first and the second signal).

Abstract: A device (10) for operating a windshield wiper (12) is proposed, with a moisture sensor (22) for detecting the wetness of a window that in addition to detecting rain and droplets also detects fog and drizzle. The measured values (Us) of the moisture sensor (22) are allocated incremental values (Ink) by the control unit (16). The difference between two successive incremental values (Ink) is to be added, with a sign (+ or −), in the memory (28) to a sum (&Sgr;) of differences formed previously in the same way, and when a threshold (S) is reached by the sum (&Sgr;) stored in the memory (28), the control unit (16) trips a wiper operating mode.