Abstract: An optically operated automatic control system for a vehicle's windshield wipers can automatically activate the windshield wipers or a water dispenser filled with cleansing agent in response to the amount of rain cast on a windshield or the level of dirtiness of the same. Thus, a clear vision is constantly kept through a windshield glass for the driver of a vehicle to see. The automatic control system is mainly equipped with a photography device at a proper position adjacent the windshield to take the vision in front of a vehicle via the windshield. Afterwards, a series of calculations via a number of preset mathematical equations are conducted so as to get the wiper control system or the water dispenser to automatically operate accordingly. Thus, the windshield glass of a vehicle can always be kept clear and clean for a driver in driving to see through any time.

Abstract: In a wiper apparatus for carrying out wiping motion with use of rotational drive of a motor, reverse rotation due to the application of external force on the wiper blade is positively detected. In response to the detection result, the motion of the motor and the wiper blade is controlled. The detection of the reverse rotation is carried our such that two kinds of periodic signals are generated depending on the rotation direction of the drive shaft, and the phase relationship between the periodic signals are arranged to differ depending on the rotation direction, and then the rotation direction is detected from the phase relationship. The wiper apparatus may be an opposing type wiper apparatus having a pair of wiper blades, and control operation of the wiper blades may be arranged such that the position taken by the wiper blade is detected by counting a number of pulses which are generated in association with the rotation of the drive shaft of the motor.

Abstract: A water drop detection sensor for detecting water drops W adhering to or present upon a windshield by detecting changes in an amount of reflection light and also for detecting the ambient brightness outside of a car or other vehicle, comprising: a windshield 2; a light emitting means 5 for introducing detection light into the windshield 2; and a light receiving means 6 for detecting reflected detection light. The reflected detection light is reflected by total internal reflection within the windshield 2, and the light emitting means 5 and said light receiving means 6 are provided on the windshield 2.

Abstract: In accordance with one aspect of the invention, a driver alert system includes a sensor, a windshield wiper of a vehicle, and circuitry. The sensor detects a predetermined condition on the vehicle. The circuitry is configured to activate the windshield wiper when the predetermined condition is detected. Additionally, a method is disclosed according to such system.

Abstract: A regulated windshield wiper device (10), in particular for motor vehicles, is proposed, which predetermines a corrected guidance variable (F) by determining a correction variable (K) so that the regulating deviation of the control circuit becomes approximately zero. In order to regulate the position (X) of at least one wiper (16) that oscillates between two end positions (18.1, 18.2, 18.3), the windshield wiper device (10) includes an electronically reversible drive motor (14) and a regulating unit (12), which compares a regulation variable (R) to a guidance variable (F) and regulates the motor (14) by means of a control variable (S), wherein the deviation between the guidance variable (F) and the regulation variable (R) and/or other parameters, e.g. the control variable (S) or variables derived from the regulation variable (R), is used to calculate a correction variable (K) with which the guidance variable (F) can be corrected.

Abstract: A synchronization system according to the present invention includes a signal generator that provides a "RUN" signal simultaneously to two or more windshield wiper motors in response to simultaneous receipt of position signals generated by the motors. Each motor generates a position signal when the windshield wiper controlled by the motor is at a predetermined position. A gate circuit monitors the output of each motor to determine whether the motor is in the predetermined position. The gate circuit provides a trigger signal to the signal generator of the present invention only when each motor outputs a position signal. The trigger signal causes the signal generator to produce a subsequent "RUN" signal initiating another wipe cycle. Accordingly, the motors begin each cycle in synchronization.

Abstract: A method and an assembly for sensing moisture (20) on the exterior surface (22) of a sheet of glass (14) by positioning an imaging lens (16) adjacent to the interior surface (18) of the sheet of glass (14), passing light rays from moisture (20) on the exterior surface (22) of the sheet of glass (14) through the imaging lens (16) and producing first and second successive images of the moisture (20) on the glass (14), and successively directing the first and second images from the lens (16) onto a focal plane detector (12). The focal plane detector (12) is divided into rows of pixels (24) which are ligned into columns. The assembly and method are characterized by scanning the pixels (24) of each row in a first scan (FIG. 4) and producing a reference value X for each pixel (24) in response to an initial image in that pixel (24), scanning the pixels (24) of each row in a second scan (FIG.

Abstract: A windshield wiper device is described for a vehicle windshield, having a wiper motor that has a reversible direction of rotation. The wiper motor is controlled by an electronic unit with control signals. The electronic unit uses an operating mode and a learning mode, with which a reversal position of a wiper arm and/or a driven shaft can be stored in memory in the learning mode and called up as often as desired in the operating mode. In this way, a wiper motor is made that can be adapted to different operating cases with different wiped areas in a simple and cost-effective manner, without mechanical changes needing to be performed.

Abstract: A moisture sensor for detecting moisture on the surface of a transparent material. The moisture sensor includes one or more emitters for producing moisture sensing signals which are influenced by moisture on the transparent material, and one or more detectors for receiving the moisture sensing signals and producing a detector output signal. The moisture sensor further includes a pre-demodulation gain and filtering circuit having high order filtering for removing most of the unwanted ambient light noise and EMI interference from the detector output signal for the accurate detection of moisture in the presence of noise.

Abstract: Proposed is a control device (50) for a windshield wiper that serves in actuating a further window wiper. The control device (50), having an inventive embodiment, includes a control (18), whose signal output (20) provides first control signals (42) for actuating the windshield wiper, preferably a front windshield wiper (26) of a motor vehicle, and whose further signal output (22) provides further control signals (42) for actuating a further windshield wiper, preferably a rear window wiper (30).

Abstract: A system for detecting the presence of rain droplets on a windshield employs a source of radiant energy, such as an LED, and a photodetector installed on the instrument panel of a vehicle. The LED and the photodiode are arranged with respect to one another such that light from the LED cannot reflect directly off the windshield onto the photodiode. Only when the light from the LED is back scattered by an environmental condition, such as the raindrops on the exterior of the windshield, the condensation of moisture on the interior of the windshield, or the presence of smoke in the cabin, will the photodiode receive the light from the LED. Each of these environmental conditions has a predeterminable characteristic signature that permits the processing of data to detect same.

Abstract: There is provided a method for controlling an opposed wiping type wiper apparatus having a pair of wiper blades driven by a pair of motors, respectively. The wiper apparatus includes detecting means for detecting the angular position of the each wiper blade, calculating means for calculating the angular distance of one wiper blade relative to the other wiper blade, memory means for memorizing therein a reference table of target angular distances in advance for the wiper blades, and control means for controlling the pair of wiper blades so that the angular distance of each of the wiper blades is brought close to the corresponding target angular distance.The wiper apparatus also may control the wiper blade velocity. In this case, the wiper apparatus further includes a reference table of target velocities and the wiper blades are controlled based on the target angular distance and target velocity.

Abstract: A control system for automatically detecting moisture on the windshield of a vehicle. The automatic moisture detecting system includes an optical system for imaging a portion of the windshield on to an image array sensor, such as a CMOS active pixel sensor. The voltages of each of the pixels which represents the illumination level is converted to a corresponding gray scale value by an analog digital converter. The gray scale values corresponding to the image are stored in memory. The spatial frequency composition of the gray scale values are analyzed to determine the amount of rain present. In order to provide a control signal to control the operation of the windshield wipers of the vehicle as a function of the amount of moisture present. The system is also adapted to detect the level of fog both on the interior of the windshield as well as the exterior of the windshield.

Abstract: The wiper control method is capable of preventing damages on a wiper due to erroneous operation of the wiper when a vehicle is subjected to a car washer with its wiper operation kept in an "AUTO" mode, and the wiper automatically operates without troubles while driving. The wiper control method is used for an automatic wiper system which automatically controls wiper operation of a vehicle by sensing the climate condition by a rain drop sensor 7, and the state of a door mirror of the vehicle is detected by a mirror folding detection switch 5. When the door mirror is folded, wiper operation control performed by the automatic wiper system is stopped so that the wiper is not operated even if the rain drop sensor 7 detects a rain drop.

Abstract: In a method and a system for the operation of a resistive moisture sensor, conductance of the sensor is measured, whereby current through the moisture sensor is measured preferably during an application of a voltage to the moisture sensor. In order to avoid electrolytic phenomena, the voltage is fed to the moisture sensor via a capacitor, and has a waveform of two pulses of different polarity following shortly one after the other.

Abstract: An apparatus and method for controlling the operation of the windshield wipers of a vehicle in response to the deposition of water on the exterior of the windshield; the operation of the air conditioning system in response to the formation of water condensation on the interior of the windshield of the vehicle; and the operation of the ventilation system in response to the presence of smoke in the cabin of the vehicle.

Abstract: A windshield wiping device includes a control amplifier 5 for controlling a wiper motor 7 in accordance with a driver's operation of a wiper switch 3. When a vehicle is energized, the control amplifier 5 once outputs a working inhibition signal to a working inhibition relay 15 in order to stop the operation of the wiper. Thus, it is possible to avoid the wiper's working against the driver's will immediately after a key switch has been switched on. When the vehicle begins to travel or the position of the wiper switch 3 is changed by the driver, then the wiper is activated in accordance with the position of the wiper switch 3.

Abstract: The use of a Gray code ganged wiper switch and an electronic circuit controlling the washer-pump motor and wiper motor allow the use of a minimal number of wires in the overall interval wiper system than found in conventional systems. Circuit redundancy and Gray coding method provides several added reliability features at a low manufacturing cost. The system further provides a resistorless control of the several power output functions of the system.

Abstract: This invention relates to a windshield wiping system and method which utilizes a rain sensor having a housing defining a first mounting area for mounting directly onto a mirror mount which is adhered to a windshield. The rain sensor housing also defines a second mounting area that defines a generally trapezoidally-shaped mount for receiving a mirror bracket in order to support a mirror. The rain sensor housing is an integral one-piece construction that automatically registers at least one sensor in operative relationship with the windshield and in a predetermined position and orientation relative to the windshield when the rain sensor is mounted on the mirror bracket.

Abstract: An arrangement for detecting moisture conditions on a pane, particularly a windshield of a motor vehicle, wherein radiation emitted by a transmitter is coupled by a radiation guide into the pane and is coupled out of the pane onto a receiver. With respect to the production and the dimensions, the design is supported by the measures which provide that the beam entry surface and/or the beam exit surface is/are arranged on the parallel side of the radiation guide facing the circuit board, and that the optical axis of the transmitter or of the receiver is oriented to be perpendicular to the beam entry surface or the beam exit surface and that the radiation guide has at least one input-end or output-end deviating surface with which the radiation that entered the radiation guide is guided at a right angle into the interior of the radiation guide or the radiation which is to be oriented out of the radiation guide onto the receiver is guided at a right angle out of the interior of the radiation guide.

Abstract: A device which determines a condition of at least one wiper blade of a motor-vehicle windshield wiper. The device includes a rain sensor controlling the motor-vehicle windshield wiper and being utilized for determining the condition of the wiper blade. The device also includes an evaluation circuit receiving data from the rain sensor. The evaluation circuit evaluates wear and tear of a rubber wiper element of the wiper blade based on one of a slow and continuous change of the data and a quick and continuous change of the data provided by the rain sensor.

Abstract: A wiper system and method for use in a wiper system on a vehicle, such as an automobile, a truck, an agricultural vehicle, and the like is shown having a wiper motor having a drive shaft which is driven at a substantially linear rate. A first gear is cooperatively coupled to the output shaft and driven thereby at the linear rate. A second gear is coupled to the first gear and it is driven in response to the movement of the drive shaft. The second gear is operatively coupled to a third gear which drives a crank which is coupled to a plurality of wiper blades via suitable linkage. The system and method are have at least one gear which is non-symmetrical about its axis which enables or cause the crank to be driven at a non-linear rate relative to the rate of the drive shaft.

Abstract: A control device associated with a wiper motor for motor vehicles, in particular a rear window wiper motor the control device permitting a rapid final test of the motor with virtually no delay. For this purpose, a certain test signal is fed to a control unit via a signal input in response to which test signal the control unit electrically charges the motor for a test mode over an extended period.

Abstract: A rain drop detecting device includes an oscillation element disposed on a plate member such as a windshield for generating an ultrasonic wave on the plate member, an ultrasonic wave receiving element disposed on the plate member for receiving the ultrasonic wave generated by the oscillation element, a detecting device connected to the ultrasonic wave receiving element for detecting an amplitude of the ultrasonic wave, and an ultrasonic wave absorbing member disposed on the plate member. The absorbing member is designed to absorb a portion of the ultrasonic wave generated by the oscillation element to prevent the downwardly travelling portion of the ultrasonic wave from travelling beyond a desired region of the plate member. In the case of a windshield, the absorbing member can be used to prevent the ultrasonic wave from travelling to the resting location of the wiper so that inadvertent rain drop detection does not occur.

Abstract: A device for operating a windshield wiper with an automatic wiper control. The wiping operation is optimally adapted to the wetting conditions of a windshield as soon as the automatic wiper control is turned on. This is achieved by a control stage which, during the switching on, triggers at least one initial wiping action when responding to an activation signal emitted by an input stage. Following the initial wiping action, the wiping operation takes place on the basis of the wetting conditions detected by the sensor unit.

Abstract: The present invention provides an element being driven by an electromagnetic device. According to the invention, the element is in mechanical communication with a noise producing device which produces noise by mechanical means. Therefore, the noise producing device produces noise indicating movement of the movable body. In another aspect of the present invention, the noise producing device may produce noise by mechanical means which indicates a position of the movable body.

Abstract: A direct drive type rear wiper in which normal and reverse rotation of a motor causes reciprocating wiping operation of a wiper blade of a vehicle such as an automobile, comprising a motor 1 which rotates in normal and reverse directions, a worm wheel 2 which rotates being interlocked with the motor 1, a relay plate 3 which rotates being interlocked with the worm wheel 2, four contacts S1-S4 provided facing the relay plate 3, and a control circuit 4 for switching direction of electric current for the motor 1. In particular, when the motor 1 is to be stopped at a turning position in reciprocating wiping operation of the wiper blade, electric braking is made to act directly on the motor 1 according to contacting condition between the relay plate 3 and the first and second contacts S1, S2.

Abstract: A wiper control device includes a wiper switch having a variable resistor which is switched to the respective resistance value corresponding to the respective operation mode of the wiper apparatus. An interface circuit is provided with a reference resistor and a capacitor. A microcomputer is provided with a reference charging port for changing the capacitor through the reference resistor, a detective charging port for changing the same capacitor through the variable resistor switched into various resistance values corresponding to the respective operation modes and a reading port for reading as to whether the capacitor is changed up to a predetermined potential level. The microcomputer determines the selected operation mode on the basis of a relative value calculated from the time required for charging the capacitor through the reference resistor by the reference charging port and the time required for charging the capacitor through the variable resistor of the wiper switch by the detective charging port.

Abstract: A sensor for detecting moisture on an outside surface of a windshield is disclosed. The sensor includes an emitter circuit for emitting light energy, and a detector circuit for receiving light energy. A processor controls the emitter circuit and processes signals received from the detector circuit. A self test circuit is connected between the processor and the emitter circuit, the self test circuit is operably associated with the emitter circuit for generating a test signal for simulating the presence of moisture on the outside surface of the windshield.

Abstract: An automatic, self-adaptive controller for varying the interval between wipes of a windshield wiper arrangement for a vehicle measures current drawn by the windshield wiper arrangement during a forward and return portions of the windshield wiper wipe cycle and calculates an integration of the current over each portion of the windshield wiper wipe cycle to establish forward portion and return portion integration. The magnitude of the portions, which graphically appear as current lobes over time, are indicative of wiper-to-windscreen friction, and hence, wetness. The difference between the forward and return integration is representative of vehicle air speed. The windshield is characterized as wet when the first and second summation values are small, and in that case, a short interval between wipes is established. When the first and second integration values are large, the windshield is deemed to be dry, and a long interval is established between wipes.

Abstract: An apparatus for intermittently controlling windshield wipers, comprising a setting switch which is capable of being manually activated, a microconller responsive to the activation of the setting switch, means for programming a time interval into the microcontroller in response to activation of said setting switch, whereby the microcontroller initiates a sweeping action of the windshield wipers corresponding to the time interval between activations of the setting switch and continues to initiate a sweeping action of the windshield wipers during the programmed time interval until a subsequent activation of the setting switch, and, either means for decreasing the time interval after setting of the programmed time interval by a single subsequent activation of the setting switch or means for increasing the time interval after setting of the programmed time interval by two subsequent activations of the setting switch. A method for intermittently controlling windshield wipers is also disclosed.

Abstract: The invention relates to an apparatus for operating a windshield wiper, having a sensor device for detecting the state of wetness of a windshield, an evaluation device that receives the sensor signal and an actuating unit for the windshield wiper that can be actuated by the evaluation device to effect suitable wiping operation. Even when individual drops impact the windshield, appropriate wiping operation can be initiated during a drying phase of the windshield, because it is provided that current measured values of the sensor signal can be supplied to both the difference-initiating stage and a drop-recognition device that is provided in the evaluation device and in which the sensor signal can be evaluated with respect to individual drops using signal breaks, and that an adapted control signal can be generated by the control-signal-generating stage when a minimum signal break is detected, with which signal corresponding wiping operation can be initiated by way of the actuating unit.

Abstract: A washer solution hose controlling device includes a car speed sensor and an electronic control device outputting a control signal in proportion to the car speed detected from the car speed sensor. The washer solution hose controlling device further employs a solenoid where the voltage supplied from the battery, depending upon the control signal output of the electronic control device which is in proportion to the car speed, is varied. Both sides of a feed hose are pushed by the solenoid to increase the injection pressure of washer solution proportionate to the detected car speed.

Abstract: A wiper motor control using a load sense resistor to monitor conditions confronting the wiper operation. The control can detect if the wiper is frozen to the window, moving too slowly, moving too quickly, etc. The power to the motor is then adjusted to achieve a desired speed, or, otherwise adjusted, based upon the detected conditions. Further, the direction of the motor may be reversed based upon the detected conditions. In a preferred embodiment, the load sense resistor is provided by a defroster filament strip. Alternatively, a temperature sensor may be used to detect the conditions confronting the wiper operation.

Abstract: A drive circuit system includes an opening control circuit Eo adapted to close an opening relay to drive a motor in a window opening direction by operation of a control switch to an opening position, and a closing control circuit Es adapted to close a closing relay to drive the motor in a window closing direction by operation of the control switch to a closing position. The opening control circuit Eo and the closing control circuit Es include final output stage transistors To and Ts, respectively, each of which comprises a PNP-type transistor. When the drive circuit system becomes wet due to the entry or condensation of water or liquid, a leak current I is permitted to flow simultaneously between bases of the final output stage transistors To and Ts and ground 2. Both of the transistors To and Ts are simultaneously turned on to close the opening relay and the closing relay.

Abstract: A control system for automatically detecting moisture on the windshield of a vehicle. The automatic moisture detecting system includes an optical system for imaging a portion of the windshield on to an image array sensor, such as a CMOS active pixel sensor. The voltages of each of the pixels which represents the illumination level is converted to a corresponding gray scale value by an analog digital converter. The gray scale values corresponding to the image are stored in memory. The spatial frequency composition of the gray scale values are analyzed to determine the amount of rain present. In order to provide a control signal to control the operation of the windshield wipers of the vehicle as a function of the amount of moisture present. The system is also adapted to detect the level of fog both on the interior of the windshield as well as the exterior of the windshield.

Abstract: A detection device has a transducer (10) for emitting and receiving series of ultrasonic pulses. An integrator (23) integrates echo signals resulting from ultrasonic pulses within a time window so as to produce an integral value. A time-delay circuit (28) is used to control the instant of opening T1 of a time window and a control circuit (25) determines an average value of a number of n integral values and for loading the values of the opening a instant T1 into the time-delay circuit (28) so as to maintain the average value at a steady value. The control circuit (25) determines the average value by loading a first value of T1 in the time-delay circuit before the integration of the first x echo signal and a second value of T1 in the time-delay circuit before the integration of the second n-x echo signals.

Abstract: A screen wiping apparatus, in particular for an opening window of a motor vehicle, comprises an electric motor which drives at least one screen wiper in oscillating motion between two reversal positions, namely a fixed inner stop position and a fixed outer stop position. In addition, the blade is able to be retracted into a parked position which lies away from the window, when the window is to be opened. The apparatus includes a control system whereby the power supply voltage to the motor is variable by adjustment between a zero voltage and a maximum or full power voltage. The control system includes means for reducing the power supply voltage to the motor when the screen wiper passes from the fixed inner stop position to the off-window parked position.

Abstract: In a rain sensor system for a motor vehicle, a sensor element is provided as separate part for attachment in the vicinity of a vehicle window. The sensor element is wiped by a separate wiper blade which is fastened to a windshield wiper or driven by the latter. As a function of the a degree of wetness present on its top, the sensor element supplies electric signals to an evaluation electronics. Above a limit value of the signals, the evaluation electronics connects the windshield wiper.

Abstract: A device for operating a windshield wiper with an automatic wiper control. A fast reaction to a suddenly occurring heavy wetting event is assured without adversely affecting the sequence of intermittent wiper operation. This is achieved by an evaluation unit which has a surge detection stage that makes it possible to detect, during intermittent operation when a sensor signal falls short of a surge threshold and by triggering a control signal for at least one wiping action when the signal falls short of the surge threshold.

Abstract: A windshield wiping arrangement with at least one wiper arm (11) is disclosed, which is operated by an electromotor (10) with reversible rotational direction. A time determination device (19) is provided, which determines the time (T.sub.n ; T.sub.n+1 ; T.sub.n+2 ; T.sub.n+3 ; T.sub.n+4) following the triggering of a wiping operation. Furthermore, a time presetting device (22) is provided, which presets a maximum allowable time (T.sub.max ; T.sub.max,n+1 ; T.sub.max,n+2 ; T.sub.max,n+3) for the duration of half of a wiping cycle. A comparator (21) detects a possibly existing time overrun and, with a time overrun signal (27), triggers a wiping operation in the opposite direction relative to the preceding wiping operation by reversing the electromotor (10). The windshield wiping arrangement according to the invention makes it possible to maintain a limited wiping operation when a blocking occurs (B1, B2, B3), as can be caused, for example, by a snow load on a windshield to be cleaned.

Abstract: A arrangement for operating a windshield wiper in a direct mode, an intermittent mode or a continuous mode, having a sensor device for detecting a degree of moisture on the windshield, an evaluation device for the sensor signal and an actuation unit for the windshield wiper. A non-disturbing smoothing of the interval times is accomplished in a simple manner in that an interval time control has a smoothing stage for the interval time with which it can be determined during which time segment of predetermined time segments within the interval time a wetting event occurs, starting from the beginning of the interval, and with which the second interval time can be shortened all the more, the earlier the time segment appears during which the wetting event occurs.

Abstract: Noise suppression system for a relay-switched windshield wiper, wherein reversal of current to a motor driving the wiper causes the motor to reverse. Filters contained within the motor, together with filters and shielding located external to the motor, suppress rf emissions.

Abstract: A wiper control system including a current sensing device is used in conjunction with a park position switch to limit the current drawn by windshield wiper motor whenever the system experiences restrictions in a park mode. The arrangement of components is effective for preventing damage to the motor and motor control system caused by excessive current draw whenever the motor stalls, arcs, or experiences excessive loads. However, the current sensing portion of the circuit is essentially disabled when the motor is in its normal operating mode thus preserving the fail safe operation of the wipers.

Abstract: A windshield wiper system and method comprising a controller which cooperates with a single sensor positioned in fixed relationship to a target situated on an armature of a drive motor which is driven in response to the controller. The wiper motor is a reversing wiper motor and changes direction in response to a change of polarity of drive signal generated by controller. An interrupt is situated on a drive train driven by the armature of the wiper motor and moves in correlation to the movement of a wiper blade. The sensor generates a pulse train associated with the movement of the wiper blade, and this pulse train gets interrupted by the interrupt when the wiper blade reaches a reversing position, such as an inwipe or an outwipe position. The interruption thereby gives controller an indication of when to reverse the polarity of the drive signal used to drive the wiper motor.

Abstract: A process and a system for the operation of a resistive moisture sensor, in particular on the windshield of a motor vehicle, wherein the conductivity of the moisture sensor is measured shortly after a sudden change in a signal fed to the moisture sensor and measured at at least one later time. Information as to the nature and degree of the dirtying of the windshield is obtained by the measured values.

Abstract: Disclosed is a multi-functional apparatus having a single electromagnetic device to drive a multiple of electrically-actuated functions. The multi-functional apparatus has an armature shaft that selectively and alternatively activates a window wiper assembly and a flexible, elongated drive element such as a cable coupled to opposing ends of the armature shaft.

Abstract: An apparatus for operating a windshield wiper having an automatic wiper control. The apparatus is provided with a rain sensor having a light-emitting transmitter and a receiver that responds to the emitted light by emitting a sensor signal, and an evaluation device for the sensor signal. The evaluation device has a microcomputer and a capacitor that is outside of the microcomputer and to which the sensor signal is supplied. Also included is a comparator connected to the capacitor for comparing the voltage built up at the capacitor by the sensor signal to a threshold voltage and for emitting an output signal if the threshold voltage is exceeded. The microcomputer forms a measured value from the output signal, the value of which correspond to a time at which the threshold is exceeded.

Abstract: A raindrop sensor of the present invention including light emitting part which emits a strip-shaped light; light receiving part which receives the strip-shaped light emitted from the light emitting means; and detecting device which detects a raindrop based on the amount of the light received by the light receiving device. The raindrop sensor of the present invention is applied to a wiper apparatus of a vehicle. The wiper apparatus includes a wiper for wiping a windshield of the vehicle, and a control unit for instructing a given wiper operation to the wiper in accordance with a given output signals from the raindrop sensor, the wiper being driven in accordance with the instruction from the control unit. Also, the wiper apparatus using the raindrop sensor is applied to a vehicle.

Abstract: The invention relates to an apparatus for operating a windshield wiper, having a sensor device for detecting the state of wetness of the windshield, an evaluating device that receives the sensor signal and in which an adjusting device is provided for updating a reference value, and an actuator unit for the windshield wiper that is actuated by the evaluating device for initiating a wiping process if the difference between the reference value and a current measured value exceeds a predetermined threshold value. The evaluation and analysis of an event that influences the sensor signal, such as a slow buildup on the windshield under drizzly or foggy conditions, are facilitated by the fact that the adjusting device includes at least one adjusting stage whose time constant is in an order of magnitude of one second to a few seconds, and that the reference value can be followed step-wise, taking into consideration all current measured values received at intervals of fractions of a second.