Sensor and wind direction / wind speed / rain amount detection device

Abstract

Provided are a sensor and a wind direction / wind speed / rain amount detection device that accurately measure both wind speed and rain amount by means of a single sensor. This sensor comprises: a piezoelectric element 20 that detects the vibration caused by Karman vortices caused by wind and also detects the impact of raindrops; and a Karman vortex generator 30 that is provided opposite the piezoelectric element 20 and generates a Karman vortex.

Description

Sensors and wind direction, speed, and rainfall detectors

[0001] The present disclosure relates to a sensor and a wind direction, wind speed, and rainfall detection device.

[0002] With the recent advances in IoT and AI technologies, it is expected that meteorological data will be used to improve productivity and create new businesses in a wide range of fields, including agriculture and retail. It is also expected that a large number of measuring devices for measuring meteorological data will be installed in the future. Examples of measuring devices for measuring meteorological data include rain gauges for rainfall and anemometers for wind speed.

[0003] For example, Patent Document 1, which is related to rain gauges, discloses a rain sensor that measures rainfall by detecting the impact of raindrops hitting a piezoelectric element. Also, Patent Document 2, which is related to anemometers, discloses a piezoelectric wind sensor that detects wind speed by detecting wind pressure when wind strikes a plurality of piezoelectric sensors 12 arranged around a solid mast 14, distorting the sensors 12 to generate electromotive force. Patent Document 2 also shows that wind direction can be detected by arranging a plurality of piezoelectric sensors 12 around the circumference and identifying the piezoelectric sensor 12 that generates the strongest signal among the plurality of piezoelectric sensors 12 arranged around the circumference.

[0004] Japanese Patent Application Laid-Open No. 2001-305241 U.S. Pat. No. 4,615,214

[0005] The rainfall sensor described in Patent Document 1 cannot measure wind speed, and the piezoelectric wind sensor described in Patent Document 2 cannot measure rainfall. In other words, it has been difficult to accurately measure both rainfall and wind speed as meteorological data using a single sensor.

[0006] The present disclosure has been made in view of the above points. That is, a main object of the present disclosure is to provide a sensor and a wind direction, speed, and rainfall detection device that can accurately measure both rainfall and wind speed with a single sensor.

[0007] The sensor of the present disclosure comprises: a piezoelectric element that detects vibrations caused by wind-induced Kármán vortices and the impact of raindrops; and a Kármán vortex generator that is positioned opposite the piezoelectric element and generates the Kármán vortex.

[0008] The wind direction, wind speed, and rainfall detecting device of the present disclosure includes at least three or more of the above-described sensors, and the sensors are arranged at the corners of a polygon in plan view.

[0009] According to the sensor and wind direction, speed, and rainfall detection device of the present disclosure, at least both rainfall and wind speed can be measured with high accuracy using a single sensor.

[0010] FIG. 1A is a schematic perspective view of the sensor of the first embodiment. FIG. 1B is a schematic perspective view of a modified example of the sensor of the first embodiment. FIG. 2 is a schematic cross-sectional view taken along the arrows II-II in FIG. 1A. FIG. 3 is a schematic perspective view of the sensor of the second embodiment. FIG. 4 is a schematic cross-sectional view taken along the arrows IV-IV in FIG. 3. FIG. 5 is a schematic bottom perspective view of the sensor of the second embodiment. FIG. 6 is a schematic bottom perspective view of another embodiment of the sensor of the second embodiment. FIG. 7 is a schematic cross-sectional view of a modified example of the sensor of the second embodiment. FIG. 8 is a partially enlarged schematic cross-sectional view of FIG. 7. FIG. 9 is a plan view of the wind direction, wind speed, and rainfall detection device of the present disclosure. FIG. 10 is a perspective view of another embodiment of the wind direction, wind speed, and rainfall detection device of the present disclosure. FIG. 11 is a graph showing rainfall measured using the sensor of the present disclosure. FIG. 12 is a graph illustrating a demonstration test of rainfall using the sensor of the present disclosure. Fig. 13 is a graph showing wind speed measured by a sensor of the present disclosure. Fig. 14 is a graph showing wind speed measured by a sensor of the present disclosure. Fig. 15 is a graph showing wind speed measured by a sensor of a comparative example. Fig. 16 is a graph illustrating a demonstration test on wind speed of the sensor of the present disclosure.

[0011] The sensor and wind direction, speed, and rainfall detection device of the present disclosure are described below. Note that the present disclosure is not limited to the following configurations and may be modified as appropriate without departing from the gist of the present disclosure. In addition, a combination of multiple individual preferred configurations described below also constitutes the present disclosure.

[0012] In this specification, terms indicating the relationship between elements (e.g., "parallel," "orthogonal," etc.) and terms indicating the shape of elements not only mean the literal and strict aspects, but also mean a range that is substantially equivalent, for example, a range that includes a difference of about a few percent.

[0013] Furthermore, in the description of this specification, references to directions or orientations are made merely for the convenience of explanation and are not intended to limit the scope of the present disclosure unless otherwise explicitly stated. For example, relative terms such as "outside (or outer, external, or outer circumference)" and "inside (or inner, internal, or inner circumference)" and their derivative terms should be understood to refer to the direction as described or illustrated. In other words, unless otherwise explicitly stated, the invention is not necessarily limited to a specific direction, orientation, form, or the like. Similarly, terms such as "provided" and "disposed" and their derivative terms may refer to a form in which other elements, such as intervening elements, are present, rather than a direct form, unless otherwise explicitly stated.

[0014] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, scale, etc. may differ from those of the actual product.

[0015] <Sensor of First Embodiment> A sensor 1a of a first embodiment of the present disclosure will be described with reference to Figures 1A to 2. The sensor 1a of the first embodiment includes a housing 10, a piezoelectric element 20, and a Karman vortex generator 30. Each component will be described in detail below.

[0016] Housing The housing 10 may be made of a metallic and / or non-metallic material. A preferred material for the housing 10 is a weather-resistant material that is resistant to deformation, discoloration, deterioration, and other changes when used outdoors. Examples of materials include metals such as stainless steel and aluminum, and weather-resistant plastics such as polyvinyl chloride, Teflon (registered trademark), and polycarbonate.

[0017] The housing 10 may include a contact portion 11 that contacts the wind and raindrops, and a support portion 12 that supports the contact portion 11. As an example of the size of the housing 10, the placement surface of the housing 10 may be approximately 5 cm x 5 cm.

[0018] The contact portion 11 may act as a protective member that protects the piezoelectric element 20 (described later) and that can appropriately transmit vibrations caused by Karman vortices (described later) and the impact of raindrops to the piezoelectric element 20. The piezoelectric element 20 may be provided on the contact portion 11 via an adhesive resin layer 13 (see FIG. 2).

[0019] It is preferable that the surface area of ​​the contact portion 11 is larger than the surface area of ​​the piezoelectric element 20. Such a relationship between the surface area of ​​the contact portion 11 and the surface area of ​​the piezoelectric element 20 reduces exposure of the piezoelectric element 20 to the outside and can appropriately protect the piezoelectric element 20 from rain and wind. Note that the contact portion 11 and the resin layer 13 do not impede the piezoelectric element 20 from detecting vibrations caused by Karman vortices and the impact of raindrops.

[0020] The contact portion 11 may be supported by the support portion 12 so as to be inclined with respect to the mounting surface of the sensor 1 a. When the contact portion 11 is supported so as to be inclined with respect to the mounting surface of the sensor 1 a, both the vibrations caused by the Karman vortex and the impact of the raindrops can be detected by the piezoelectric element 20.

[0021] In the embodiment shown in Figures 1A and 2, the inclination angle of the contact portion 11 of the sensor 1a relative to the mounting surface may be approximately 45°. This inclination angle allows the piezoelectric element 20 to detect both vibrations caused by Kármán vortices and the impact of raindrops. Note that if the inclination angle is greater than 45° (for example, approximately 60°), it becomes easier to detect vibrations caused by Kármán vortices than the impact of raindrops. On the other hand, if the inclination angle is smaller than 45° (for example, approximately 30°), it becomes easier to detect the impact of raindrops than the vibrations caused by Kármán vortices.

[0022] - Piezoelectric Element - The piezoelectric element 20 includes a piezoelectric body 23 that generates an electromotive force when a force (pressure) is applied, a first electrode 21 provided on one main surface of the piezoelectric body 23, and a second electrode 22 provided on the other main surface opposite the one main surface of the piezoelectric body 23 (see FIG. 2). When vibrations caused by Karman vortices and the impact of raindrops are applied to the piezoelectric element 20, the piezoelectric body 23 bends and generates an electromotive force due to the piezoelectric effect, and the electromotive force is detected from the first electrode 21 and the second electrode 22.

[0023] Suitable materials for the piezoelectric element 23 that detects vibrations caused by raindrop impacts and Karman vortices include organic piezoelectric elements such as polymeric piezoelectric films made of vinylidene fluoride or its copolymers, and inorganic piezoelectric elements such as barium titanate, lead zirconate titanate, and potassium sodium niobate. These materials can adequately detect vibrations caused by raindrop impacts and Karman vortices.

[0024] - Karman Vortex Generator - The Karman vortex generator 30 is a structure that is disposed opposite the piezoelectric element 20 and generates Karman vortices. In this specification, the term "Karman vortex" refers to a periodic vortex that occurs downstream when an object is placed in a fluid flow. If the frequency of the periodic vortex is f, the flow velocity is v, and the width of the Karman vortex generator is d, then the following equation (1) holds: f = St v / d (Equation 1)

[0025] Here, St is a constant (Strouhal number) determined by the shape and dimensions of the Karman vortex generator 30. When the Karman vortex generator 30 is cylindrical, the Reynolds number is 500 to 2×10 ５ It is known that the frequency f of the Karman vortex is approximately 0.2 in the range of 1 / f. Therefore, by measuring the frequency f of the Karman vortex, the flow velocity v can be calculated, and the calculated flow velocity v can be correlated with the wind speed.

[0026] The material of the Karman vortex generator 30 may be a weather-resistant material that is resistant to deformation, discoloration, deterioration, and other changes when used outdoors, similar to the material of the housing 10. More specifically, the material may be the same as that of the housing 10, or a different material.

[0027] <Method of Measuring Rainfall and Wind Speed ​​Using the Sensor of the First Embodiment> Next, a method of measuring rainfall and wind speed using the sensor 1a of the first embodiment described above will be described in detail.

[0028] The amount of rain is measured by detecting the electromotive force and its frequency generated by the piezoelectric effect when raindrops strike the contact portion 11 and bend the piezoelectric element 20. When this electromotive force is detected from the first electrode 21 and the second electrode 22, the size of the raindrops can be calculated in accordance with the magnitude of the electromotive force. The frequency of raindrop collisions can also be calculated from the frequency of the electromotive force. The product of the magnitude and frequency of the electromotive force is the amount of rain. In other words, the amount of rain is calculated based on the electromotive force detected by the piezoelectric element 20 and its frequency. Specifically, when there is a lot of rain, the electromotive force and its frequency detected by the piezoelectric element 20 will be large, and when there is little rain, the electromotive force and its frequency detected by the piezoelectric element 20 will be small.

[0029] In rainfall measurement, it is known that raindrops generally have a diameter of approximately 1 mm to 5 mm. For example, if raindrops with a diameter of 5 mm and a rainfall rate of 50 mm per hour strike a piezoelectric element 20 measuring 5 cm x 5 cm, the calculated frequency is once every 1.88 seconds. Therefore, the frequency with which the piezoelectric element 20 is deflected by raindrops striking it is sufficiently low compared to the frequency with which the piezoelectric element 20 is deflected by vibrations caused by Kármán vortices generated by the Kármán vortex generator 30, which will be described later. Therefore, because the frequency of the vibrations caused by Kármán vortices differs from the frequency of the signal caused by the raindrops, it is possible to distinguish between the rainfall measurement results and the wind speed measurement results, which will be described later.

[0030] The wind speed is measured by having wind strike the Kármán vortex generator 30, generating Kármán vortices downstream of the Kármán vortex generator 30 in the wind's blowing direction, and then detecting the vibrations caused by the Kármán vortices with the piezoelectric element 20. Specifically, the vibrations caused by the Kármán vortices cause the piezoelectric element 20 to periodically deflect, generating an electromotive force, and measuring the frequency f of the vibrations. Once the frequency f is determined, the flow velocity v is calculated using the above-mentioned equation (1), and the calculated flow velocity v corresponds to the wind speed. Here, if the wind speed is fast, the frequency detected by the piezoelectric element 20 becomes large, and if the wind speed is slow, the frequency detected by the piezoelectric element 20 becomes small.

[0031] 1A and 2, the sensor 1a of the first embodiment can accurately measure at least both rainfall and wind speed. In other words, rainfall can be determined by measuring the electromotive force and its frequency due to the piezoelectric effect of the piezoelectric element 20, which is generated by the impact of raindrops. Wind speed can be determined by measuring the frequency of the vibrations of Kármán vortices generated downstream of the Kármán vortex generator 30 in the wind direction. Furthermore, because the measurement principles for rainfall measurement (measuring the magnitude and frequency of the single electromotive force generated by raindrops) and wind speed measurement (measuring the frequency of the continuous vibrations generated by Kármán vortices) are different, the piezoelectric element 20 allows for accurate measurement of both rainfall and wind speed with a single sensor.

[0032] <Additional Features of the Sensor of the First Embodiment> In a preferred embodiment of the sensor 1a, the piezoelectric element 20 may be disposed at an angle relative to the mounting surface of the sensor 1a. In one example, as shown in Fig. 1A, the piezoelectric element 20 may be disposed at an angle of approximately 45° relative to the mounting surface of the sensor 1a. By disposing the piezoelectric element 20 at an angle relative to the mounting surface of the sensor 1a in this manner, the piezoelectric element 20 can simultaneously detect raindrops falling substantially perpendicular to the mounting surface of the sensor 1a and wind blowing substantially parallel to the mounting surface of the sensor 1a.

[0033] The surface of the Karman vortex generator 30 that the wind hits may be curved. In the example shown in Figure 1A, the Karman vortex generator 30 may be cylindrical. By curving the surface of the Karman vortex generator 30 that the wind hits, the Strouhal number can be kept constant at about 0.2, and the wind speed can be calculated appropriately using the above-mentioned (Equation 1).

[0034] As a method for further distinguishing between rainfall measurement and wind speed measurement, the sensor 1a of the first embodiment may include a filter circuit (not shown) that separates signals resulting from vibrations caused by Kármán vortices and signals resulting from raindrop impacts from the signals detected by the piezoelectric element 20. One example of a filter circuit may be a filter circuit that uses a predetermined frequency as a reference and extracts frequencies higher than that reference frequency as signals resulting from vibrations caused by Kármán vortices and frequencies lower than that reference frequency as signals resulting from raindrop impacts. As described in detail in "Method for Measuring Rainfall and Wind Speed ​​Using the Sensor of the First Embodiment," the frequency at which the piezoelectric element 20 bends when raindrops strike it is sufficiently lower than the frequency at which the piezoelectric element 20 bends due to vibrations caused by Kármán vortices generated by the Kármán vortex generator 30, which will be described later. Therefore, the frequency of the signal generated when the piezoelectric element 20 bends when raindrops strike it is lower than the frequency of the signal generated when the piezoelectric element 20 bends due to vibrations caused by Kármán vortices. Therefore, by providing the sensor with a filter circuit, it is possible to more accurately distinguish between rainfall measurement and wind speed measurement. As will be explained in the examples below, the distinction between rainfall measurement and wind speed measurement may be made by comparing the electromotive force of the piezoelectric element when measuring rainfall and the electromotive force of the piezoelectric element when measuring wind speed.

[0035] <Modification of the sensor of the first embodiment> Next, a modification of the sensor of the first embodiment will be described with reference to Fig. 1B. In describing the modification of the sensor of the first embodiment, explanation of points common to the explanation in the above section [Sensor of the first embodiment] will be omitted as appropriate. In other words, the following description will focus on points that are different from the explanation in the above section [Sensor of the first embodiment].

[0036] In the modified sensor, the piezoelectric element 20 may be rectangular or fibrous (fiber-like) and may have a high aspect ratio structure with an aspect ratio of 2 or more. The term "aspect ratio" as used herein refers to the ratio between the long side and the short side of a rectangular or fibrous piezoelectric element 20. By increasing the aspect ratio of the piezoelectric element 20 to 2 or more, the deflection of the piezoelectric element 20 increases, making it easier to generate the piezoelectric effect. This allows for improved accuracy in measuring rainfall and wind speed.

[0037] In the sensor of the modified example, the Karman vortex shedder 30 may be arranged so as to intersect with the long side direction of the rectangular piezoelectric element 20. By arranging the Karman vortex shedder 30 in this manner, the piezoelectric element 20 can more appropriately detect Karman vortices that are generated downstream of the Karman vortex shedder 30 in the wind blowing direction.

[0038] <Sensor of Second Embodiment> Next, a sensor 1b of a second embodiment will be described with reference to FIGS. 3 to 6. The sensor 1b of the second embodiment differs from the sensor 1a of the first embodiment in that it can detect wind direction in addition to measuring rainfall and wind speed. In describing the sensor 1b of the second embodiment, explanations of points in common with the above description will be omitted as appropriate. In other words, the following description will focus on points that are different from the above description.

[0039] Housing The housing 10 of the sensor 1b of the second embodiment may be dome-shaped. In this specification, the term "dome-shaped" refers to a shape obtained by rotating an arch having an upwardly convex curved apex around a central axis perpendicular to the horizontal plane. As an example, a hemispherical or semi-elliptical shape is intended.

[0040] The curved portion 14 of the dome-shaped housing 10 is a position that is exposed to wind and rain. In other words, the sensor 1b of the second embodiment may be exposed to wind and rain from all directions of the housing 10. Therefore, the curved portion 14 may act as a protective member that can appropriately transmit vibrations caused by Karman vortices (described below) and the impact of raindrops to the piezoelectric element 20.

[0041] A piezoelectric element 20 may be provided on the back side of the curved portion 14 via an adhesive resin layer 13 (see FIG. 4). The contact portion 11 and the resin layer 13 do not impede the detection of vibrations caused by Karman vortices and the impact of raindrops by the piezoelectric element 20. The resin layer 13 may be provided on the entire back side of the curved portion 14, or may be provided on only a part of the back side of the curved portion 14.

[0042] Piezoelectric Element The piezoelectric element 20 includes a piezoelectric body 23, a first electrode 21 provided on one main surface of the piezoelectric body 23, and a second electrode 22 provided on the other main surface opposite the one main surface of the piezoelectric body 23 (see FIG. 4). In addition, in FIG. 5, which shows an example, the first electrode 21 and the piezoelectric body 23 may be provided on the entire back side of the curved portion 14, and the second electrodes 22 may be provided radially from the center of the apex of the dome shape. According to the aspect shown in FIG. 5, different detection signals resulting from the deflection of the piezoelectric body 23 can be extracted from each of the radially arranged second electrodes 22 (electrodes that detect the deflection of the piezoelectric element 20). In other words, the sensor 1b of the second embodiment is equivalent to having multiple piezoelectric elements arranged, because different signals can be extracted from the radially arranged second electrodes 22. 5, the first electrode 21 may be provided on the entire back side of the curved portion 14, and the piezoelectric body 23 and the second electrode 22 may be provided radially from the center of the apex of the dome shape, as shown in FIG. 6. Even in this configuration, different signals can be extracted from the radially arranged second electrodes 22.

[0043] - Karman vortex generator - The Karman vortex generator 30 is arranged to surround the piezoelectric element 20. This allows Karman vortices to be generated downstream of the Karman vortex generator 30 in the wind's direction, even if wind hits the Karman vortex generator 30 from all directions.

[0044] <Method for Measuring Rainfall and Wind Speed ​​and Direction Using the Sensor of the Second Embodiment> Next, a method for measuring rainfall and wind speed and direction using the sensor 1b of the second embodiment will be described in detail.

[0045] The amount of rain is measured by detecting the electromotive force and its frequency generated by the piezoelectric effect when raindrops strike the curved portion 14 and bend the piezoelectric element 20. When the electromotive force is detected from the first electrode 21 and the second electrode 22, the amount of rain can be calculated based on the magnitude and frequency of the electromotive force. In other words, the amount of rain is calculated based on the electromotive force detected by the piezoelectric element 20 and its frequency. Specifically, when the amount of rain is heavy, the electromotive force and its frequency detected by the piezoelectric element 20 become large, and when the amount of rain is light, the electromotive force and its frequency detected by the piezoelectric element 20 become small.

[0046] The wind speed is measured when wind strikes the Kármán vortex generator 30, generating Kármán vortices downstream of the Kármán vortex generator 30 in the wind's direction, and the piezoelectric element 20 detects the vibrations caused by the Kármán vortices. Specifically, the vibrations caused by the Kármán vortices cause the piezoelectric element 20 to periodically deflect, generating an electromotive force, and the frequency f of the vibrations is measured. Once the frequency f is determined, the flow velocity v is calculated using the above-mentioned equation (1), and the calculated flow velocity v corresponds to the wind speed. Here, if the wind speed is fast, the frequency detected by the piezoelectric element 20 becomes large, and if the wind speed is slow, the frequency detected by the piezoelectric element 20 becomes small.

[0047] The wind direction can be determined by detecting signals from each of the piezoelectric elements 20 arranged radially from the center of the dome shape. Specifically, signals from each of the piezoelectric elements 20 are detected, and the piezoelectric element 20 with the largest signal is extracted, and the direction in which the piezoelectric element 20 is located can be determined as the wind direction. For example, in the embodiment shown in Figure 5 or Figure 6, the second electrode 22 that generates the largest signal can be extracted from the signals detected from the multiple second electrodes 22, and the direction of the second electrode 22 can be determined as the wind direction.

[0048] In a more preferred embodiment, signals from each piezoelectric element 20 are detected, and the piezoelectric element 20 with the largest signal is extracted (e.g., the piezoelectric element 20 with the largest signal), and the piezoelectric element 20 adjacent to the piezoelectric element 20 is also extracted. By comparing the signal intensity ratios of adjacent piezoelectric elements, the position between the two piezoelectric elements 20 corresponding to the signal intensity ratio may be determined as the wind direction. For example, in the embodiment shown in FIG. 5 or FIG. 6, the signal intensity ratio between the signal detected from the second electrode 22a and the signal detected from the second electrode 22b adjacent to the second electrode 22a may be calculated, and the position corresponding to the signal intensity ratio may be determined as the wind direction. In this embodiment, the wind direction can be determined more accurately by calculating the signal intensity ratio of the detected signals.

[0049] As described above, the sensor 1b of the second embodiment can detect the wind direction in addition to measuring the amount of rainfall and wind speed.

[0050] <Modification of the Sensor of the Second Embodiment> Next, a modification of the sensor 1b of the second embodiment will be described with reference to Figs. 7 and 8. In describing the modification of the sensor of the second embodiment, the description of points common to the description in the above section [Sensor of the Second Embodiment] will be omitted as appropriate. In other words, the following description will focus on points that are different from the description in the above section [Sensor of the Second Embodiment].

[0051] In the sensor of the modified example, the piezoelectric element 20 includes a first piezoelectric element 20a disposed opposite the Karman vortex shedder 30 and a second piezoelectric element 20b vertically adjacent to the first piezoelectric element 20a, and the second piezoelectric element 20b may be disposed obliquely relative to the first piezoelectric element 20a (see, in particular, FIG. 8 ). In the embodiment shown in FIGS. 7 and 8 , two second piezoelectric elements 20b are provided, and the first piezoelectric element 20a is disposed vertically between the plurality of second piezoelectric elements 20b.

[0052] According to the sensor of the modified example, the Karman vortex from the Karman vortex generator 30 can be detected by the second piezoelectric element 20b adjacent in the vertical direction in addition to the first piezoelectric element 20a arranged radially. Therefore, unlike the sensor of the second embodiment, it is possible to detect not only the horizontal wind direction but also the vertical wind direction. In other words, it is possible to determine the wind direction in three dimensions.

[0053] <Wind direction, wind speed, and rainfall detection device> Next, the wind direction, wind speed, and rainfall detection device 2 of the present disclosure will be described with reference to Figures 9 and 10. In describing the wind direction, wind speed, and rainfall detection device 2, explanations of points common to the above description will be omitted as appropriate. In other words, the following description will focus on points that are different from the above description.

[0054] The wind direction, wind speed, and rainfall detection device 2 of the present disclosure includes at least n sensors 1a (n is a natural number equal to or greater than 3) of the first embodiment, each disposed at a corner of a regular n-sided polygon in plan view. In the example shown in Figure 9, three sensors 1a of the first embodiment are provided, each disposed at a corner of an equilateral triangle in plan view. The angle between adjacent sensors 1a may be 120°.

[0055] According to the wind direction, wind speed, and rainfall detection device 2 of the present disclosure, as described for the sensor 1a of the first embodiment, it is possible to measure rainfall and wind speed for each sensor 1a. Furthermore, it is possible to detect signals from each sensor 1a, extract the sensor 1a with the largest signal, and determine the direction in which the sensor 1a is located as the wind direction. Furthermore, it is also possible to extract the sensor with the largest signal and its adjacent sensor, calculate the signal strength ratio between the two sensors, and determine the wind direction as the position between the two sensors that corresponds to the signal strength ratio.

[0056] Instead of the embodiment shown in FIG. 9, three sensors may be combined into one package as shown in FIG.

[0057] A demonstration test of the sensor of the present disclosure will be described below. Specifically, rainfall and wind speed were measured using the sensor shown in FIG. 1A.

[0058] [Rainfall Measurement] Figure 11 shows a graph of rainfall measured using the sensor shown in Figure 1A. Figure 11 shows electromotive force data of the piezoelectric element when a raindrop with a diameter of 1 mm and a speed of 1.4 m / s hits the sensor. According to the data shown in Figure 11, when a raindrop hits the sensor, an electromotive force of about 0.03 V (30 mV) was detected.

[0059] 12, when the vertical axis represents the product of the electromotive force and the number of times that raindrops hit the sensor, and the horizontal axis represents the amount of precipitation, a proportional relationship was confirmed, as shown in the graph. Therefore, it was confirmed that the amount of rain can be measured using the sensor of the present disclosure.

[0060] [Wind Speed ​​Measurement] Graphs of wind speed measured using the sensor shown in Figure 1A are shown in Figures 13 to 16. Figure 13 shows electromotive force data of the piezoelectric element when there is no wind, and Figure 14 shows electromotive force data of the piezoelectric element that detected vibrations caused by Kármán vortices generated by a Kármán vortex generator at a wind speed of 1.0 m / s. For reference, Figure 15 shows electromotive force data of the piezoelectric element at a wind speed of 1.0 m / s when no Kármán vortex generator is installed, as a comparative example.

[0061] According to the data shown in Figures 13 and 14, the piezoelectric element did not detect any electromotive force when there was no wind, but when the wind speed was 1.0 m / s, Kármán vortices were generated, and regular vibrations were detected at a predetermined frequency f. Furthermore, the electromotive force detected by the piezoelectric element in this case was approximately 2 mV, which was approximately 0.1 times the electromotive force detected by the piezoelectric element when rainwater struck the sensor. It was also possible to distinguish between detected rainfall and detected wind speed based on this electromotive force. On the other hand, with the sensor without a Kármán vortex generator, irregular vibrations were generated, as shown in Figure 15, and the frequency could not be calculated from the graph.

[0062] 16, when the vertical axis represents the frequency of the Karman vortex and the horizontal axis represents the wind speed, a proportional relationship was confirmed as shown in the graph. Therefore, it was confirmed that the sensor of the present disclosure can measure wind speed.

[0063] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. The technical scope of the present disclosure also includes all modifications within the scope and meaning equivalent to the claims.

[0064] The sensor and wind direction, wind speed, and rainfall detection device of the present disclosure include the following aspects: <1> A sensor comprising: a piezoelectric element that detects vibrations caused by wind-induced Karman vortices and the impact of raindrops; and a Karman vortex shedder that is arranged opposite the piezoelectric element and generates the Karman vortex. <2> The sensor described in <1>, in which the piezoelectric element is arranged at an angle with respect to a mounting surface of the sensor. <3> The sensor described in <1> or <2>, in which the piezoelectric element is rectangular or fibrous and has a high aspect ratio structure with an aspect ratio of 2 or more. <4> The sensor described in any one of <1> to <3>, in which the surface of the Karman vortex shedder that the wind hits is curved. <5> The sensor described in any one of <1> to <4>, in which the Karman vortex shedder is arranged so as to intersect with the long side direction of the rectangular piezoelectric element. <6> The sensor according to any one of <1> to <5>, further comprising a filter circuit that separates signals resulting from vibrations caused by the Karman vortices and signals resulting from the impact of raindrops from signals detected by the piezoelectric elements. <7> The sensor according to any one of <1> to <6>, wherein the Karman vortex shedder is arranged to surround the piezoelectric elements. <8> The sensor according to any one of <1> to <7>, wherein the sensor is dome-shaped. <9> The sensor according to <8>, wherein the piezoelectric elements are arranged radially from the center of the dome shape. <10> The sensor according to <9>, wherein signals from each of the radially arranged piezoelectric elements are detected, and wind direction is determined based on the piezoelectric element with the highest signal strength. <11> The sensor according to <10>, wherein signals from each of the radially arranged piezoelectric elements are detected, and wind direction is determined based on the signal strength ratio between the piezoelectric element with the highest signal strength and the piezoelectric element adjacent to that piezoelectric element. <12> The sensor described in <8> or <11>, wherein the piezoelectric element is arranged corresponding to the curved surface of the dome shape, and electrodes for detecting the deflection of the piezoelectric element are arranged radially from the center of the dome shape.<13> The sensor according to <7> or any one of <8> to <12> citing <7>, wherein the piezoelectric element comprises a first piezoelectric element arranged opposite the Karman vortex generator and a second piezoelectric element adjacent to the first piezoelectric element in the vertical direction, and the second piezoelectric element is arranged diagonally with respect to the first piezoelectric element. <14> A wind direction, wind speed, and rainfall detection device comprising at least n sensors according to any one of <1> to <13> (n is a natural number of 3 or more), and the sensors are arranged at the corners of a regular n-gon in a plan view.

[0065] The sensor and wind direction, speed, and rainfall detection device of the present disclosure can be suitably used as an electronic component that can accurately measure at least both rainfall and wind speed with a single sensor.

[0066] 1a 1b Sensor 2 Wind direction, wind speed, and rainfall detection device 10 Housing 11 Contact portion 12 Support portion 13 Resin layer 14 Curved portion 20 Piezoelectric element 21 First electrode 22 Second electrode 23 Piezoelectric body 30 Karman vortex generator

Claims

1. A sensor comprising: a piezoelectric element that detects vibrations caused by wind-induced Karman vortices and the impact of raindrops; and a Karman vortex generator that is positioned opposite the piezoelectric element and generates the Karman vortices.

2. The sensor according to claim 1, wherein the piezoelectric element is disposed at an angle relative to a surface on which the sensor is placed.

3. The sensor according to claim 1 or 2, wherein the piezoelectric element is rectangular or fibrous and has a high aspect ratio structure with an aspect ratio of 2 or more.

4. A sensor according to any one of claims 1 to 3, wherein the surface of the Karman vortex generator that is exposed to the wind is curved.

5. A sensor according to any one of claims 1 to 4, wherein the Karman vortex generator is arranged so as to intersect with the long side direction of the rectangular or fiber-shaped piezoelectric element.

6. A sensor as described in any one of claims 1 to 5, comprising a filter circuit that separates signals resulting from vibrations caused by the Karman vortex and signals resulting from the impact of the raindrops from the signals detected by the piezoelectric element.

7. A sensor according to any one of claims 1 to 6, wherein the Karman vortex generator is arranged to surround the piezoelectric element.

8. The sensor according to any one of claims 1 to 7, which is dome-shaped.

9. The sensor according to claim 8, wherein the piezoelectric elements are arranged radially from the center of the dome shape.

10. The sensor according to claim 9, wherein the sensor detects signals from each of the radially arranged piezoelectric elements and determines the wind direction based on the piezoelectric element with the highest signal strength.

11. The sensor of claim 10, which detects signals from each of the radially arranged piezoelectric elements and determines wind direction based on the signal strength ratio between a piezoelectric element with a high signal strength and the piezoelectric element adjacent to that piezoelectric element.

12. A sensor as described in claim 8 or 11, wherein the piezoelectric element is arranged corresponding to the curved surface of the dome shape, and electrodes for detecting the deflection of the piezoelectric element are arranged radially from the center of the dome shape.

13. A sensor as described in claim 7 or any one of claims 8 to 12 that cites claim 7, wherein the piezoelectric element comprises a first piezoelectric element arranged opposite the Karman vortex generator and a second piezoelectric element vertically adjacent to the first piezoelectric element, and the second piezoelectric element is arranged obliquely relative to the first piezoelectric element.

14. A wind direction, wind speed, and rainfall detection device comprising at least n sensors according to any one of claims 1 to 13 (n being a natural number of 3 or greater), the sensors being arranged at each corner of a regular n-gon in plan view.

Images