KR20090126754A - Rain sensor for vehicle and sensing method thereof - Google Patents

Abstract

PURPOSE: A rain sensor for vehicle and a sensing method thereof are provided to sense rainfall, a high frequency noise, and a wiper noise at the same time by using the capacitance variation of a condenser. CONSTITUTION: A rain sensor for vehicle(1) comprises a circuit board(12) for rainfall sensing. The circuit board comprises a first sensor, a second sensor, and an MICOM(Microcomputer). The first sensor senses rainfall. The first sensor outputs a first signal in which an output value is changed according to the detected rainfall. The second sensor outputs a second signal in which an output value is changed by external high frequency. According to difference between the output values of the first signal and the second signal, the MICOM controls the working speed of a wiper.

Description

Rain sensor for vehicle and sensing method

The present invention relates to a vehicle rain sensor and a method for sensing the same for controlling the wiper operation of the vehicle, and more specifically, by using a plurality of capacitive sensors accurately detect the amount of rain water falling on the windshield of the vehicle and accordingly A rain sensor for a vehicle for efficiently controlling the operation of a wiper and a sensing method thereof.

Recently, as automobiles are popularized, automobiles are spreading rapidly across various classes and ages, and the technical trend of the automobile industry is to break away from the conventional mechanical point of view such as engines, and to electronicize each system for driver's convenience. And the situation is gradually changing to intelligent.

Recently, as a part of the electronic and intelligent of the vehicle, a technology for a vehicle rain sensor that attempts to automatically control the operation of the vehicle wiper according to the rainfall has been developed, so that the rain sensor for the vehicle does not operate the wiper in rainy weather. It detects and controls the wiper's operation automatically.

Conventional vehicle rain sensor has a light emitting unit and a light receiving unit inside the windshield of the vehicle, and the optical conduction to determine the rainfall by using the change in the intensity of light generated by the change in the refractive index of the light due to rain drops (rain drops) The method was mainly used.

However, the conventional optical sensor has a problem that the structure and installation is complicated and the cost of parts is high, leading to an increase in production cost, and the measurement accuracy is low because the measurement area is small and affected by contaminants. Had a problem.

Therefore, in order to solve this problem, a capacitive rain sensor for detecting rainfall using a change in capacitance of a capacitor installed inside the windshield of a vehicle has been recently developed, and the configuration and sensing principle of the rain sensor using the capacitive sensor Is disclosed in detail in the following [Document 1].

However, even in the rain sensor disclosed in [Document 1], when the vehicle is exposed to a high frequency (RF) environment such as a wireless communication area, the noise generated by the external high frequency (hereinafter referred to as 'high frequency noise'). It has a problem that the sensing accuracy is lowered due to the influence.

In addition, since the rain sensor senses rainfall and once the wiper is operated, noise generated by the wiper operation (hereinafter, referred to as “wiper noise”) cannot be taken into consideration. In case of passing, there is a problem in that the wiper is operated at a high speed due to a misjudgment that the rainfall is large even when the rainfall is actually small.

[Document 1] Republic of Korea Patent Registration No. 10-781744 (Dec. 4, 2007 registration notice)

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to detect all of the rainfall, high frequency noise and wiper noise by using a plurality of capacitors and the By removing the high frequency noise and the wiper noise, it is to provide a vehicle rain sensor and a sensing method that can detect the rainfall significantly more stably and precisely than the capacitive vehicle rain sensor according to the prior art.

In order to achieve the above object, the present invention, in the rain sensor for a vehicle comprising a rainfall detection circuit board on the inside of the housing that one side is attached to the glass of the vehicle, the circuit board detects the rainfall and according to the detected rainfall A first sensor unit for outputting a first signal having a fluctuating output value, a second sensor unit for outputting a second signal having a fluctuating output value due to an external high frequency signal, and a difference between an output value of the inputted first signal and the second signal (net) characterized in that it comprises a microcomputer for controlling the operating speed of the wiper according to the output value.

In addition, the microcomputer determines whether the wiper is in operation when the net output value is less than a preset value, and when the wiper is in operation, receives the first and second signals again.

The first sensor unit may include a plurality of first sensor units, and the microcomputer calculates a sum of an output value difference between the first signal output from each first sensor unit and the second signal output from the second sensor unit as the net output value. It features.

In addition, each of the first sensor units may be sequentially arranged on the same plane, and the microcomputer may output the first signal output from each of the first sensor units located at both ends of the plurality of first sensor units and the second sensor unit. When at least one of the difference between the output value of the second signal is less than the set value, it is determined whether the wiper is in operation.

In addition, the first sensor unit is installed on the first circuit board provided on one side of the housing attached to the glass of the vehicle, the second sensor unit is provided to be spaced apart from the influence of the first circuit board and the electric field It is characterized in that installed on the two circuit board.

The first sensor unit and the second sensor unit respectively correspond to a capacitor for charging and discharging the power supplied from the input power according to a cycle determined by an input power and a capacitance, and a charge and discharge cycle of the capacitor. And an integrated circuit for outputting a first signal or a second signal, which is a pulse signal, wherein the capacitor of the first sensor unit changes capacitance when raindrops or wipers are interposed between two terminals for charging electric charges. The output value of the first signal and the second signal is characterized in that the number or frequency of each pulse.

The first sensor unit and the second sensor unit may each include a capacitor, a signal generator for applying a power signal having a constant frequency to the capacitor, and a first signal or a second modulated frequency of the power signal according to the capacitance of the capacitor. And a frequency converting circuit for outputting a signal, wherein the capacitor of the first sensor unit changes capacitance when raindrops or wipers are interposed between two terminals for charging a charge, and output values of the first signal and the second signal. Is characterized in that each frequency.

In addition, the present invention is a sensing method of a rain sensor for a vehicle comprising a rainfall detection circuit board inside the housing that one side is attached to the glass of the vehicle, using a rainfall sensor and a noise sensor respectively rainfall and external high frequency And a second step of sensing a net output value, which is a difference between output values of the rainfall sensor and the noise sensor, and controlling an operating speed of the wiper according to the calculated net output value. Characterized in that.

The second step may determine whether the wiper is in operation when the calculated net output value is less than a preset value, and if the wiper is in operation, performs the first step again.

A rain sensor for a vehicle and a sensing method thereof according to the present invention configure a sensor unit to simultaneously detect rainfall, high frequency noise, and wiper noise using a change in capacitance of a capacitor, and exclude the influence of the noise in calculating the actual rainfall. Compared to the capacitive rain sensor according to the technology, there is an advantage that it is possible to detect the actual rainfall with remarkably stable and precise.

For this reason, the vehicle rain sensor and the sensing method according to the present invention has the advantage that it is possible to improve the convenience of the driver in the rain by controlling the wiper to operate efficiently in response to the actual amount of rainfall.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 is a cross-sectional view showing the installation structure of a vehicle rain sensor according to a first embodiment of the present invention. In the vehicle rain sensor 1 of FIG. 1, a first PCB substrate 12 and a second PCB substrate 13 are provided inside a hexahedral housing 11, and the housing 11 is connected to the vehicle by an adhesive member 14. The front glass 20 is configured to be attached to the inside.

Since the first PCB substrate 12 has a sensor portion for detecting rainfall as will be described later, the first PCB substrate 12 is provided on an adhesive surface side of the housing 11, and the second PCB substrate 13 has a sensor portion for detecting external high frequency noise. Therefore, it is preferable to be provided in the back side of the housing 11.

In addition, the adhesive member 14 may be preferably composed of a double-sided tape, such that the first PCB substrate 12 may be installed in close contact with the front glass 20 of the vehicle.

In addition, the second PCB substrate 13 may be fixed to the rear surface of the housing 11 by using a coupling member such as a double-sided tape or a screw, so as not to be affected by an electric field formed on the first PCB substrate 12. Preferably, the first PCB 12 is spaced apart from the predetermined distance.

In addition, the second PCB substrate 13 is installed to be slightly spaced apart from the rear surface of the housing 11 when fixed through the coupling member in order to prevent the influence of moisture or dust that may occur inside and outside the rear surface of the housing 11. It is preferable.

2A and 2B are plan views illustrating configurations of the first PCB 12 and the second PCB 13 according to an embodiment of the present invention, respectively.

The first PCB substrate 12 is provided with first to third sensor units 15, 16, and 17 sequentially on the same plane, and each of the sensor units 15, 16, and 17 will be described later. Likewise, by forming independent sensor circuits to detect the rainfall generated outside the windshield 20 of the vehicle.

Meanwhile, the second PCB 13 includes a fourth sensor unit 18 for detecting high frequency noise affecting the entire vehicle rain sensor 1, and for controlling the operation of the vehicle rain sensor 1 according to the present invention. A microcomputer (not shown) and an external connection interface (not shown) are provided.

Figure 3 is a schematic diagram showing the operation principle of the first to third sensor unit of the vehicle rain sensor according to an embodiment of the present invention. Since the operation principles of the first to third sensor units 15, 16, and 17 are all the same, the first sensor unit 15 will be described below by way of example.

The first sensor unit 15 is used to charge and discharge cycles of the input power 33, the first capacitor 31 for charging and discharging the power supplied from the input power 33, and the first capacitor 31. And a first integrated circuit 32 for outputting a digital signal including the frequency information.

The first capacitor 31 is composed of a 'c' shaped first terminal 15a and a second terminal 15b formed inside the first terminal 15a. Unlike the present embodiment, the first terminal Both the 15a and the second terminal 15b may be formed in a straight line.

In this case, an upper portion of the first terminal 15a and the second terminal 15b corresponds to a medium space 15c formed between the anode plates of a conventional capacitor, and the first sensor unit 15 is the medium space 15c. Rainfall is detected by using the capacitance change of the first capacitor 31 generated when the rain is mediated.

That is, when a DC voltage Vin is applied from the input power supply 33, the first capacitor 31 connected to the first integrated circuit 32 repeats charging and discharging, and the repetition period of the first capacitor 31 is repeated. It is configured to change according to the capacitance change.

To this end, the first integrated circuit 32 is preferably configured by any one of the known IC oscillator circuit, in this embodiment, a voltage controlled oscillator (VCO) such as a 555 timer is used.

As described above, the first integrated circuit 32 applied in the present embodiment outputs a pulse-shaped signal. In this case, the frequency information may be any one of the pulse number and the frequency of the pulse signal. Hereinafter, the description will be limited to frequencies for the convenience of description).

Accordingly, the vehicle rain sensor 1 according to the present invention has a capacitance of the first capacitor 31 generated when there is no material mediated in the medium space 15c of the first capacitor 31 and when a raindrop is mediated. Rainfall can be detected using the change and the difference between the frequency information of the output signal of the first sensor unit 15 generated in both cases.

In addition, the first sensor unit 15 may detect the wiper when the wiper is mediated in the medium space 15c by the same principle, in which case the magnitude of the frequency difference of the output signal compared to the case of the raindrop mediation. Is discriminated against.

As an example, since the size difference of the frequency difference generated when the rain is mediated is several tens to several hundred times larger than the frequency difference generated when the wiper is mediated, the vehicle rain sensor 1 according to the present invention uses the same. Wiper noise generated during rainfall detection can be detected.

As described above, the vehicle rain sensor 1 according to the present invention detects rainfall or wiper noise by using the frequency of the output signal of each of the sensor units 15, 16, and 17 that vary depending on whether the raindrop or the wiper is mediated. The detailed detection method will be described later.

On the other hand, since the external high-frequency noise may be included in the output signals of the first to third sensor units 15, 16 and 17, the sensing accuracy of the rain sensor 1 according to the present invention should be improved only by removing them. You can do it.

To this end, the vehicle rain sensor 1 according to the present invention detects high frequency noise by using the fourth sensor unit 18 installed on the second PCB substrate 13, and detects the detected high frequency noise component by using the first to third sensors. It is configured to remove from the output signal of the sensor unit 15, 16, 17 will be described in detail below.

First, the configuration and operation principle of the fourth sensor unit 18 is basically the same as the first to third sensor unit (15, 16, 17), but in the case of the fourth sensor unit 18 constitutes a capacitor Since there is no raindrop or wiper mediated in the medium space (not shown) formed between the first and second terminals 18a and 18b, when there is no external high frequency noise, the frequency of the signal output from the fourth sensor unit 18 is The difference is that it is always constant.

However, when external high frequency noise is generated, the frequency of the signal output from the fourth sensor unit 18 may be changed by an electromagnetic interference phenomenon such as EMI (electro magnetic inferference) or RFI (radio frequency interference). This phenomenon is similarly generated in the first to third sensor units 15, 16, and 17.

Accordingly, the vehicle rain sensor 1 according to the present invention uses the high frequency noise component detected by the fourth sensor unit 18 to output signals from the first to third sensor units 15, 16, and 17. By removing the same noise component included, it is possible to improve the measurement accuracy of the vehicle rain sensor 1 according to the present invention.

In this case, in order to further improve the measurement accuracy of the vehicle rain sensor 1 according to the present invention, the first sensor unit so that the high frequency noise components detected by each sensor unit 15, 16, 17, 18 may be the same. It is preferable to constitute the fourth sensor unit 15, 16, 17, 18.

To this end, as an example, the input power supply 33 for supplying power to the first to fourth sensor parts 15, 16, 17, and 18 is configured identically, or power is supplied from one input power supply 33. It is preferable to comprise so that.

On the other hand, the cause of the high frequency noise generated from the outside may be caused by noise generated in a wireless communication area such as a control tower, radar base, or other military facility, noise by wireless communication of a vehicle driver, or operation of an electronic device installed inside the vehicle. Noise and the like.

In addition, the first terminals 15a, 16a, 17a, 18a and the second terminals 15b, 16b, 17b, and 18b of the respective sensor units 15, 16, 17, and 18 may be formed on the first PCB substrate 12 or, respectively. It is formed on the same plane of the second PCB substrate 13, it can be preferably implemented using a conductive material such as copper, aluminum, silver, conductive elastomer, conductive plastic, conductive rubber.

In addition, the first terminal (15a, 16a, 17a, 18a) and the second terminal (15b, 16b, 17b, 18b) is the first PCB substrate 12 by using a variety of installation methods such as bonding, pressing or spraying Or it may be preferably installed on the second PCB substrate 13.

Figure 4 is a block diagram showing the overall operation of the vehicle rain sensor according to an embodiment of the present invention.

In the vehicle rain sensor 1 according to the present embodiment, when power is supplied from the input power source 32 to the first to fourth sensor units 15, 16, 17, and 18, the respective sensor units 15, 16, 17 and 18 output digital signals (pulse signals) having frequency information by the above-described method.

The signals output from the respective sensor units 15, 16, 17, and 18 are transmitted to the control microcomputer 50 installed in the second PCB substrate 13, and the microcomputer 50 uses the wiper noise as described below. And actual rainfall with high frequency noise removed.

When the actual rainfall is calculated as described above, the microcomputer 50 connects the control signal for operating the wiper according to the operating speed of the wiper previously stored in the memory 70 to the second PCB 13 in response to the calculated actual rainfall. The wiper driver 60 outputs the result.

In this case, the wiper driver 60 may be installed on the second PCB 13 as necessary. In addition, in the present exemplary embodiment, the case in which three sensor units are installed on the first PCB 12 is described as an example, but it may be installed in two or four or more as necessary.

5 is a flowchart illustrating a sensing method of a vehicle rain sensor according to an exemplary embodiment of the present invention.

When the driving of the vehicle is started, the microcomputer 50 may generate respective frequencies f ₁ , f ₂ , from the digital signals output from the first to fourth sensor units 15, 16, 17, and 18 in the manner described above. f ₃ and f ₄ ) are detected (S110).

When the step S110 is completed, the microcomputer 50 is included in the signal output from the first sensor unit to the third sensor unit 15, 16, 17 by using the frequency of the digital signal output from the fourth sensor unit 18. The net frequencies Net f ₁ , Net f ₂ , and Net f ₃ from which the high frequency noise components are removed are calculated (S120).

At this time, the net frequency (Net f ₁ , Net f ₂ , Net f ₃ ) is the fourth sensor unit 18 at the frequency of each signal output from the first to third sensor unit (15, 16, 17) It is calculated by subtracting the frequency of the signal output from.

When the step S120 is completed, the microcomputer 50 may generate the net frequencies Net f ₁ , of the signals output from the first sensor unit 15 and the third sensor unit 17 located at both end sides of the first PCB substrate 12. It is determined whether Net f ₃ ) is all greater than or equal to the _set frequency f _set (S130).

In this case, the set frequency f _set is a value which is predetermined by an experiment and stored in the memory 70, and is output from the first to third sensor parts 15, 16, and 17 when the wiper is sensed. It is preferable to set the frequency of the signal to be.

In addition, in the present embodiment, it is determined whether the wiper noise is included only for the sensor units 15 and 17 located at both end sides of the first PCB substrate 12 for efficiency of operation. It may be configured to judge only one sensor unit.

If the net frequencies Net f ₁ and Net f ₃ are all higher than or equal to the set frequency f _set , the microcomputer 50 may include the first to third sensor units 15, 16, and 17. It is determined that the wiper noise is not interposed in the signal output from the calculated result of adding the net frequency (Net f ₁ , Net f ₂ , Net f ₃ ) of these as the actual rainfall (S150).

In this embodiment, the case where the sum of the net frequencies Net f ₁ , Net f ₂ and Net f ₃ is calculated as the actual rainfall is described as an example. However, the net frequencies Net f ₁ , Net f ₂ , Net f 3 are described. It is of course possible to calculate the actual rainfall using the rainfall data previously stored in the memory 70 in response to the sum of ₃ ).

On the other hand, if any one of the net frequency (Net f ₁ , Net f ₃ ) is less than the set frequency (f _set ) as a result of the determination in step S130, the microcomputer 50 is whether the wiper driver 60 is On (On) state. Determine (S140).

If the wiper driver 60 is turned on, the microcomputer 50 determines that the wiper noise is interposed in the signals output from the first to third sensor units 15, 16, and 17. Follow step S110.

On the other hand, if the wiper driver 60 is not in the ON state as a result of the determination in step S140, the microcomputer 50 may wiper noise to the signals output from the first to third sensor units 15, 16, and 17. Determine that there is no intervening and performs step S150.

When the step S150 is completed, the microcomputer 50 determines the proper operating speed of the wiper according to the calculated actual rainfall (S160), and transmits a control signal for driving the wiper according to the determined speed to the wiper driver 60 ( S170).

At this time, the memory 70 preferably stores data on the wiper operation speed corresponding to the calculated actual rainfall (in this embodiment, corresponds to the sum of the net frequencies).

When the step S170 is completed, the microcomputer 50 determines whether the driving of the vehicle has ended (S180), and if it is not terminated, performs the step S110 again and ends the control if it is terminated.

According to the above-described method, the vehicle rain sensor 1 according to the present invention can remove the external high frequency noise component and the wiper noise component included in the rainfall detected by the sensor unit. There is an advantage that it can be detected.

In addition, due to this, the rain sensor 1 for a vehicle according to the present invention has an advantage in that it can always control the operating speed of the wiper to match the actual rainfall, unlike the prior art.

In addition, in the present embodiment, the case in which the three sensor units of the first PCB substrate 12 for detecting rainfall has been described. However, it is a matter of course that the sensor unit may include a plurality of sensor units, including one sensor unit.

Unlike the first embodiment described above, in the step S120 the microcomputer 50 is output from the respective sensor unit 15, 16, 17, 18 using the reference frequency f ₀ stored in advance in the memory 70 The frequency change amounts Δf ₁ , Δf ₂ , Δf ₃ , Δf _{4 of the} signal are calculated, and the respective sensor units 15, 16, are obtained using the calculated frequency changes Δf ₁ , Δf ₂ , Δf ₃ , Δf ₄ . It is also possible to calculate the net frequency of 17).

In this case, the reference frequency f ₀ is a frequency of a signal output from the first to fourth sensor units 15, 16, 17, and 18 in the absence of rainfall, wiper noise, and high frequency noise. (Δf ₁ , Δf ₂ , Δf ₃ , Δf ₄ ) is a value corresponding to the difference between the respective frequencies (f ₁ , f ₂ , f ₃ , f ₄ ) detected in step S110 and the reference frequency f ₀ . do.

In this case, the set frequency f _set in step S130 is _set to the frequency change amount of the signal output from the first to third sensor units 15, 16, and 17 when the wiper is sensed.

In the above description, the microcomputer 50 detects rainfall or the like using the frequency of the digital signal (ie, the pulse signal) output from the sensor units 15, 16, 17, and 18 as an example. It is of course possible to detect rainfall by counting the number of pulses of the signal.

6 is a schematic view showing the operation principle of the first to third sensor units of the rain sensor for a vehicle according to the second embodiment of the present invention, the same components as the first embodiment are given the same reference numerals Omit the description.

In addition, since the operation principles of the first to third sensor units 15, 16, and 17 are the same as in the first embodiment, the first sensor unit 15 will be described below by way of example. .

The first sensor unit 15 has a predetermined frequency at a first capacitor 31 having two terminals 15a and 15b for charging electric charges, and a first terminal 15a of the first capacitor 31. And a first frequency conversion circuit 132 for converting the capacitance change of the first capacitor 31 into a frequency signal.

As in the first embodiment, the first sensor unit 15 having the above configuration detects rainfall using the change in capacitance of the first capacitor 31 generated when a raindrop is mediated in the medium space 15c. do.

That is, the first frequency conversion circuit 132 electrically connected to the first capacitor 31 measures the frequency of the power signal applied from the signal generator 133 and the capacitance of the first capacitor 31 generated by the raindrop. The modulated signal is output at a specific frequency corresponding to the change.

In this case, the first frequency conversion circuit 132 is preferably configured to form an oscillation circuit such as an LC circuit, an RC circuit, or an RLC circuit together with the first capacitor 31 to perform this function.

For example, when the first frequency conversion circuit 132 forms an LC circuit together with the first capacitor 31 and there is no material mediated in the medium space 15c of the first capacitor 31, 1 Capacitor 31 has a capacitance of C ₀ In this case, the frequency f ₀ of the signal output from the first frequency conversion circuit 132 may be obtained as 1 / {2π (LC ₀ ) ^1/2 }.

On the contrary, in the above example, when the capacitance of the first capacitor 31 is changed to C ₁ due to a raindrop in the medium space 15c of the first capacitor 31, the first frequency conversion circuit 132 is output. The frequency f ₁ of the signal may be calculated as 1 / {2π (LC ₁ ) ^1/2 }.

Therefore, the rain sensor 1 for a vehicle according to the present exemplary embodiment is generated in a case where there is no material mediated in the medium space 15c of the first capacitor 31 and when a raindrop is mediated, as in the first exemplary embodiment. Rainfall can be detected using the change in capacitance of the one capacitor 31 and the frequency difference between the output signals of the first sensor unit 15 generated in both cases.

In addition to the above-described operating principles of the sensor units 15, 16, and 17, the detection method of the wiper noise or the high frequency noise and the sensing method of the vehicle rain sensor 1 are the same as those of the first embodiment, and thus, redundant descriptions thereof will be omitted.

1 is a cross-sectional view showing an installation structure of a vehicle rain sensor according to a first embodiment of the present invention;

2A and 2B are plan views illustrating configurations of a first PCB substrate and a second PCB substrate included in the vehicle rain sensor shown in FIG. 1;

3 is a schematic view showing an operation principle of first to third sensor units included in the vehicle rain sensor shown in FIG. 1;

4 is a block diagram showing the overall operation of the vehicle rain sensor shown in FIG.

FIG. 5 is a flowchart illustrating a sensing method of a vehicle rain sensor shown in FIG. 1;

6 is a schematic diagram illustrating an operation principle of first to third sensor units included in a vehicle rain sensor according to a second exemplary embodiment of the present invention.

Claims (11)

In the rain sensor for a vehicle comprising a rainfall detection circuit board on one side of the housing attached to the glass of the vehicle, the circuit board, A first sensor unit which detects a rainfall and outputs a first signal whose output value changes according to the detected rainfall; A second sensor unit outputting a second signal whose output value is changed by an external high frequency wave; And And a microcomputer for controlling an operating speed of the wiper according to a net output value that is a difference between the input values of the first signal and the second signal. The method of claim 1, The micom determines whether the wiper is in operation when the net output value is less than a preset value, and if the wiper is in operation, receives the first and second signals again. The method of claim 2, The first sensor unit is a plurality, And the micom calculates the sum of the difference between the output values of the first signal output from each first sensor unit and the second signal output from the second sensor unit as the net output value. The method of claim 3, Each of the first sensor units is sequentially arranged on the same plane, The microcomputer may be configured when the at least one of a difference between an output value of the first signal output from each of the first sensor units located at both ends of the plurality of first sensor units and the second signal output from the second sensor unit is less than the set value. Rain sensor for a vehicle, characterized in that for determining whether the wiper is in operation. The method of claim 4, wherein The first sensor unit is installed on the first circuit board provided on one side of the housing attached to the glass of the vehicle, The second sensor unit is a vehicle rain sensor, characterized in that installed on the second circuit board provided spaced apart from the influence of the first circuit board and the electric field. The method according to any one of claims 1 to 5, The first sensor unit and the second sensor unit respectively charge and discharge the power supplied from the input power according to a period determined by the input power and the capacitance, and a pulse signal corresponding to the charge and discharge cycle of the capacitor An integrated circuit for outputting a first signal or a second signal, The capacitor of the first sensor unit changes capacitance when a raindrop or a wiper is mediated between two terminals for charging a charge. The output value of the first signal and the second signal is a vehicle rain sensor, characterized in that each pulse number or frequency. The method according to any one of claims 1 to 5, The first sensor unit and the second sensor unit respectively receive a capacitor, a signal generator for applying a power signal of a constant frequency to the capacitor, and a first signal or a second signal that modulates the frequency of the power signal according to the capacitance of the capacitor. Including a frequency conversion circuit for outputting, The capacitor of the first sensor unit changes capacitance when a raindrop or a wiper is mediated between two terminals for charging a charge. And the output values of the first signal and the second signal are respective frequencies. In the sensing method of a rain sensor for a vehicle comprising a rainfall detection circuit board in the housing that one side is attached to the glass of the vehicle, A first step of sensing high-frequency noise due to rainfall and external high-frequency using a rainfall sensor and a noise sensor; and And a second step of calculating a net output value that is a difference between output values of the rainfall sensor and the noise sensor, and controlling an operating speed of the wiper according to the calculated net output value. . The method of claim 8, The second step determines whether the wiper is in operation when the calculated net output value is less than a preset value, and if the wiper is in operation, performs the first step again. Sensing method. The method of claim 9, The first step is to sense the rainfall independently using a plurality of rainfall sensor, The second step is a sensing method of a rain sensor for a vehicle, characterized in that to calculate the sum of the difference between the output value of each rainfall sensor and the noise sensor as the net output value. The method of claim 10, Each of the rainfall sensor is sequentially arranged on the same plane, The second step is a vehicle lane, characterized in that for determining whether the wiper is in operation when at least one of the difference between the output value of the rainfall sensor and the noise sensor located at both ends of the plurality of rainfall sensor is less than the set value. Sensor sensing method.

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