Measuring device with a sensor for detecting moisture

Abstract

To provide a technique for stably measuring the concentration or the physical property of a measurement target substance in soil even if the soil contains a small amount of water.SOLUTION: A measurement device according to an aspect of the present disclosure is a measurement device having a sensor for detecting water. The measurement device includes: a plurality of electrodes provided in soil at least partially; a sensor for detecting water; and a measurement unit for measuring the potentials of two of the electrodes on the basis of a signal output from the sensor and measuring the concentration or the physical property of the measurement target substance in the soil on the basis of the measured potentials.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measuring device having a sensor for detecting moisture. [Background technology]

[0002] Measuring devices capable of measuring the concentration and physical properties of ions or molecules have been disclosed (e.g., Patent Documents 1-3). Also, devices that detect rain or snow and measure the ion concentration contained therein have been disclosed (e.g., Patent Documents 4-7). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4195938 [Patent Document 2] Patent No. 5267824 [Patent Document 3] Japanese Patent Application Publication No. 60-259947 [Patent Document 4] Patent No. 3018726 [Patent Document 5] Japanese Patent Application Publication No. 5-273172 [Patent Document 6] Japanese Patent Application Laid-Open No. 63-180837 [Patent Document 7] Publication No. 59-071161 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in the case of the measuring device described in Patent Document 1, the potential difference between the working electrode and the reference electrode is measured when the solution comes into contact with the working electrode, and the concentration or physical properties of the ion to be measured in the solution are calculated based on the measured potential difference. Therefore, when such a measuring device is placed in soil to measure the concentration or physical properties of the substance to be measured in the soil, it is thought that the measurement will be unstable if the moisture content of the soil is low.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a technology that can stably measure the concentration or physical properties of a substance to be measured in soil, even in soil with a low moisture content. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention employs the following configuration.

[0007] That is, a measuring device according to one aspect of the present invention comprises a plurality of electrodes, at least a portion of which is disposed in the soil, a sensor for detecting moisture, and a measuring unit for measuring the potential of at least any two of the plurality of electrodes based on a signal output from the sensor, and for measuring the concentration or physical properties of a substance to be measured contained in the soil based on the measured potential.

[0008] This configuration allows for the detection of moisture due to rainfall and the application of a voltage between at least two of the multiple electrodes. In this case, the target substance dissolved in the water that fell on the soil moves between the electrodes. Therefore, the measured potential of the two electrodes corresponds to the concentration of the target substance. This makes it possible to stably measure the concentration or physical properties of the target substance even in soil with a low moisture content.

[0009] In the measurement device according to the above aspect, the plurality of electrodes include an electrode set consisting of a pair of a first electrode and a second electrode, the first electrode and the second electrode being provided in the soil; The two electrodes may be the first electrode and the second electrode.

[0010] This configuration allows the detection of moisture due to rainfall and the application of a voltage between the first and second electrodes. In this case, the target substance dissolved in the water that fell on the soil moves between the electrodes. Therefore, the measured potentials of the first and second electrodes correspond to the concentration of the target substance. This makes it possible to stably measure the concentration or physical properties of the target substance even in soil with a low moisture content.

[0011] In the measuring device according to the above aspect, the substance to be measured moves in the direction of the first electrode when a voltage is applied between the first electrode and the second electrode, and the measuring device may further include a filter that covers the first electrode and allows the substance to be measured to pass through.

[0012] This configuration prevents sand and mud that flows with rain from coming into contact with the first electrode, thereby improving the durability of the first electrode and reducing the impact on measurement accuracy caused by sand and mud adhering to the first electrode.

[0013] The measuring device according to the above aspect may further include a power source that supplies power to the measuring unit.

[0014] This configuration allows the measurement device to operate without connecting to an external power source, making it possible to measure the concentration or physical properties of the target substance even in soil that is so large that connecting to an external power source is difficult.

[0015] In the measuring device according to the aforementioned aspect, the plurality of electrodes may include a plurality of electrode sets each consisting of a pair of electrodes.

[0016] With this configuration, when multiple electrode sets are placed at different depths in the soil, the relationship between the change in concentration or physical properties of the target substance over time and the depth in the soil can be obtained, thereby enabling detailed measurement of the leaching of the target substance from the soil due to environmental changes such as rainfall.

[0017] In the measurement device according to the aforementioned aspect, the measurement section may change the interval at which the potential is measured based on the signal output from the sensor.

[0018] According to this configuration, the measurement device can be driven in response to an environmental change event such as rainfall to measure the concentration or physical properties of the target substance. Alternatively, the measurement frequency of the measurement device can be increased in response to an environmental change event such as rainfall. This makes it possible to measure the effect of environmental changes on the concentration or physical properties of the target substance in soil. Furthermore, if this configuration further includes a power supply, the power consumption of the power supply can also be reduced. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a technique that can stably measure the concentration or physical properties of a substance to be measured in soil even if the soil has a low moisture content. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 illustrates an overview of a measurement device according to an embodiment. [Figure 2] FIG. 2 illustrates an outline of a flowchart of the measurement operation of the measurement device according to the embodiment. [Figure 3] FIG. 3 illustrates an overview of a measurement device according to a first modified example. [Figure 4] FIG. 4 illustrates an outline of a flowchart of the measurement operation of the measurement device according to the first modification. [Figure 5] FIG. 5 illustrates an overview of a measurement device according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0021] [Embodiment] FIG. 1 illustrates an overview of a measuring device 1 according to this embodiment. FIG. 1(A) is an example of an external perspective view of the measuring device 1. FIG. 1(B) is an example of a side view of the measuring device 1. The measuring device 1 is portable and is placed so as to be inserted into soil 11. It measures the concentration of a substance contained in the soil 11 that responds immediately to the growth of agricultural crops. The substance that responds immediately to the growth of agricultural crops is, for example, nitrate nitrogen (an example of a "substance to be measured" in the present disclosure).

[0022] More specifically, the measuring device 1 has an electrode set consisting of a pair of working electrode 2 and reference electrode 3. Therefore, a part of the soil 11 is present between the working electrode 2 and the reference electrode 3. Here, the moisture content of the soil 11 is, for example, less than 20%. The working electrode 2 is a so-called ion-selective electrode, and its surface is covered with a sensitive membrane. The sensitive membrane is a membrane that can selectively capture nitrate nitrogen. The sensitive membrane is, for example, a lacquer matrix liquid membrane or PVC (polychlorinated vinyl acetate) membrane. The working electrode 2 is a silver-silver chloride electrode immersed in, for example, KCL (potassium chloride). The working electrode 2 is an example of the "first electrode" of the present disclosure. The reference electrode 3 is an example of the "second electrode" of the present disclosure.

[0023] The measuring device 1 also has a measuring unit 4. The measuring unit 4 is provided in the atmosphere, outside the soil, above the working electrode 2 and the reference electrode 3. The measuring unit 4 is electrically connected to the working electrode 2 and the reference electrode 3, respectively, and the connection is protected by a case 5. The measuring unit 4 is also electrically connected to a power source external to the measuring device 1 (not shown). The diameter of the case 5 is, for example, 2 cm or less. The measuring unit 4 is an example of the "measuring unit" of the present disclosure.

[0024] The measurement unit 4 is provided with, for example, a processor such as a CPU, and storage devices such as RAM and ROM. Various programs are stored in the storage device. The stored programs are then loaded into a working area of ​​the main storage device and executed. Through the execution of the programs, various components are controlled, such as applying a voltage between the working electrode 2 and the reference electrode 3, measuring the potentials of the working electrode 2 and the reference electrode 3, and calculating the concentration of nitrate nitrogen from the potential difference between the working electrode 2 and the reference electrode 3, thereby realizing various functions that meet a predetermined purpose.

[0025] The measuring device 1 also has a rain sensor 6. The rain sensor 6 is, for example, an optical sensor. The rain sensor 6 is provided on the measuring unit 4 so as to be exposed to the atmosphere. The rain sensor 6 is electrically connected to the measuring unit 4. The rain sensor 6 may be replaced by a sensor capable of detecting water by other methods. The rain sensor 6 is an example of a "sensor" in the present disclosure.

[0026] [Example of operation] Next, an example of an outline of the measurement operation of the measurement device 1 will be described. FIG.

[0027] (S01) In step S01, the measurement unit 4 determines whether or not it is raining based on the output from the rain sensor 6.

[0028] (S02) In step S02, if the measuring unit 4 determines that it is raining in step S01, In this case, a voltage is applied between the working electrode 2 and the reference electrode 3. The voltage is applied so that the working electrode 2 acts as the anode and the reference electrode 3 acts as the cathode. Then, the nitrate nitrogen present between the working electrode 2 and the reference electrode 3 and bound to the moisture contained in the soil 11 is an anion, and therefore moves toward the working electrode 2, which is the anode. The nitrate nitrogen is then captured by the sensitive film covering the outer surface of the working electrode 2.

[0029] (S03) In step S03, the measurement unit 4 measures the potentials of the working electrode 2 and the reference electrode 3, and calculates the potential difference between the two potentials. Then, the measurement unit 4 compares the calculated potential difference with a reference potential difference to calculate the concentration of nitrate nitrogen contained in the soil 11 relative to the reference concentration of nitrate nitrogen. Note that the concentration of nitrate nitrogen contained in the soil 11 may be calculated from the absolute value of the potential difference without comparing the calculated potential difference with the reference potential difference.

[0030] [Actions and Effects] The measuring device 1 described above detects moisture due to rainfall and starts measuring the nitrate nitrogen concentration, thereby measuring the nitrate nitrogen concentration when the amount of moisture in the soil 11 has increased. The nitrate nitrogen concentration can be measured stably even in soil 11 with a low volumetric water content. This allows the nitrate nitrogen concentration to be precisely controlled in real time, thereby improving the yield and quality of agricultural crops.

[0031] [Variation 1] FIG. 3 illustrates an overview of a measurement device 1A according to a first modification. The measurement device 1A according to the first modification has the same configuration as the measurement device 1 according to the embodiment. The measurement device 1 further includes an independent power supply 12. The independent power supply 12 is provided, for example, between the measurement unit 4A and the rain sensor 6A. The independent power supply 12 supplies power to the measurement unit 4A and the rain sensor 6A.

[0032] The measuring device 1A also has a filter 7 that covers the working electrode 2A. The filter 7 prevents sand, mud, and the like contained in the soil 11 from adhering to the working electrode 2A, while allowing nitrate nitrogen to pass through.

[0033] [Example of operation] Next, an example of an outline of the measurement operation of the measurement device 1A will be described below: Fig. 4 shows an example of an outline of a flowchart of the measurement operation of the measurement device 1A.

[0034] (S1) In step S1, the measurement unit 4A determines whether or not the rain sensor 6A has detected rain.

[0035] (S2) In step S2, if it is determined that rain has been detected in step S1, the measurement unit 4A determines whether the current measurement mode is normal mode or rain mode. Note that the normal mode is a mode in which the nitrate nitrogen concentration is measured, for example, once a day (an example of a predetermined timing). The rain mode is a mode in which the nitrate nitrogen concentration is measured more frequently than in the normal mode, for example, once an hour (an example of a predetermined timing).

[0036] (S3) In step S3, if it is determined in step S2 that the measurement mode is the normal mode, the measurement unit 4A changes the measurement mode to the rain mode, which has a short measurement interval.

[0037] (S4) In step S4, if it is determined in step S2 that the measurement mode is the rain mode, the measurement unit 4A maintains the measurement mode in the rain mode.

[0038] (S5) In step S5, if it is determined that rain has not been detected in step S1, the measurement unit 4A determines whether the current measurement mode is the normal mode or the rain mode.

[0039] (S6) In step S6, if it is determined in step S5 that the measurement mode is the normal mode, the measurement unit 4A maintains the measurement mode in the normal mode.

[0040] (S7) In step S7, if it is determined in step S5 that the measurement mode is the rain mode, the measurement unit 4A changes the measurement mode to the normal mode, which has a long measurement interval and can suppress consumption of the battery 12.

[0041] (S8) In step S8, the measurement unit 4A applies a voltage between the working electrode 2A and the reference electrode 3A at a predetermined timing for each measurement mode. The voltage is applied so that the working electrode 2A serves as the anode and the reference electrode 3A serves as the cathode. As a result, nitrate nitrogen present between the working electrode 2A and the reference electrode 3A and bound to water migrates toward the working electrode 2A. The nitrate nitrogen is then captured by the sensitive film covering the outer surface of the working electrode 2A.

[0042] (S9) In step S9, the measurement unit 4A measures the potential of the working electrode 2A and the potential of the reference electrode 3A and calculates the potential difference between the two potentials. Then, the measurement unit 4A compares the calculated potential difference with a reference potential difference to calculate the concentration of nitrate nitrogen contained in the soil 11 relative to the reference concentration of nitrate nitrogen. Note that the concentration of nitrate nitrogen contained in the soil 11 may be calculated from the absolute value of the potential difference without comparing the calculated potential difference with the reference potential difference.

[0043] [Actions and Effects] The measuring device 1A described above can operate without connecting to an external power source, making it possible to measure the concentration of nitrate nitrogen even in large soil 11 that has a low volumetric water content and is difficult to supply power from an external power source.

[0044] Furthermore, with the above-described measuring device 1A, the frequency of nitrate nitrogen concentration measurements increases when moisture due to rainfall or the like is detected, and conversely, the frequency of nitrate nitrogen concentration measurements decreases when moisture is not detected. Therefore, by adjusting the measurement interval by the measuring device 1A in response to environmental change events such as rainfall, it is possible to reduce the power consumption of the independent power source 12 while measuring the impact of environmental change events such as rainfall on the nitrate nitrogen concentration in the soil 11.

[0045] Furthermore, in the measuring device 1A described above, the working electrode 2A is covered with the filter 7, which prevents sand and mud that washes with rain from contacting the working electrode 2A. This can improve the durability of the working electrode 2A. Furthermore, the effect of sand and mud adhering to the working electrode 2A on measurement accuracy is reduced.

[0046] [Variation 2] FIG. 5 illustrates an outline of a measurement device 1B according to a second modification. The measurement device 1B according to the second modification has two pairs of electrodes, each of which is made up of a pair of a working electrode and a reference electrode. The device 1B has an electrode set consisting of a pair of working electrode 2B and reference electrode 3B, and an electrode set consisting of a pair of working electrode 2C and reference electrode 3C. The working electrode 2B and the reference electrode 3B protrude from the inside of the case 5B toward the soil 11 outside at a point in the depth direction. The working electrode 2C and the reference electrode 3C are also positioned deeper in the soil 11 than the working electrode 2B and the reference electrode 3B.

[0047] [Actions and Effects] According to the measuring device 1B described above, the working electrode 2B and the reference electrode 3B, and the working electrode 2C and the reference electrode 3C are provided at different depths in the soil 11, respectively, thereby obtaining the relationship between the change in the concentration of nitrate nitrogen over time and the depth in the soil 11. This makes it possible to measure in more detail the leaching of nitrate nitrogen from the soil 11 due to environmental change events such as rainfall.

[0048] [Other variations] In the measuring device 1A according to the first modification, the frequency of measuring the nitrate nitrogen concentration when moisture due to rainfall or the like is detected is not limited to the example described above. For example, the nitrate nitrogen concentration may not be measured when moisture is not detected, and may be measured at predetermined intervals when moisture is detected. Even with this measuring device, the impact of environmental changes such as rainfall on the nitrate nitrogen concentration in the soil 11 can be measured while reducing the power consumption of the independent power source 12. The measurement interval can also be adjusted as appropriate.

[0049] Although the above embodiment shows an example of measuring the concentration of nitrate nitrogen, the concentration of other substances may also be measured. In such cases, the sensitive membrane is changed to a membrane that selectively captures other substances. Furthermore, the potential difference information between the working electrode 2 and the reference electrode 3 may be used to measure physical properties such as the diffusion coefficient of nitrate nitrogen. Furthermore, the concentration or physical properties of nitrate nitrogen may be measured using only the potential information of the working electrode 2. Furthermore, the measuring device 1 does not need to be portable.

[0050] The features described in the embodiments and modifications disclosed above can be combined with each other. [Explanation of symbols]

[0051] 1, 1A, 1B: Measuring device 2, 2A, 2B, 2C: Working electrode 3, 3A, 3B, 3C: Reference electrode 4, 4A: Measuring section 5, 5B: Case 6, 6A: Rain sensor 7: Filter 11: Soil 12: Independent power supply

Claims

1. A measuring device having a sensor for detecting moisture, a plurality of electrodes, at least a portion of which is disposed in the soil; A sensor that detects moisture; a measuring unit that measures the potential of at least any two of the plurality of electrodes based on the signal output from the sensor, and measures the concentration of the measurement target substance contained in the soil based on the measured potential; Measuring equipment.

2. The plurality of electrodes include an electrode set consisting of a pair of a first electrode and a second electrode, the first electrode and the second electrode are provided in the soil, The two electrodes are the first electrode and the second electrode. The measuring device according to claim 1 .

3. When a voltage is applied between the first electrode and the second electrode, the substance to be measured moves toward the first electrode, The measuring device further includes a filter that is provided to cover the first electrode and allows the measurement target substance to pass through. The measuring device according to claim 2 .

4. Further comprising a power supply that supplies power to the measurement unit. The measuring device according to claim 2 .

5. The plurality of electrodes includes a plurality of electrode sets each consisting of a pair of electrodes. The measuring device according to claim 2 .

6. the measurement unit changes the measurement interval of the potential based on the signal output from the sensor.

5. The measuring device according to claim 4.

Images