JP2023080958A - Measurement device having sensor for detecting water - Google Patents

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

The present invention relates to a measuring device equipped with a sensor for detecting moisture.

Measuring devices capable of measuring the concentration, physical properties, etc. of ions or molecules have been disclosed (eg, Patent Documents 1 to 3). Further, a device for detecting rain or snow and measuring the concentration of ions contained therein has been disclosed (for example, Patent Documents 4 to 7).

Japanese Patent No. 4195938 Japanese Patent No. 5267824 JP-A-60-259947 Japanese Patent No. 3018726 JP-A-5-273172 JP-A-63-180837 Japanese Utility Model No. 59-071161

For example, in the case of the measurement device described in Patent Document 1, the potential difference between the working electrode and the reference electrode is measured by contacting the solution with the working electrode, and based on the measured potential difference, the ions to be measured in the solution Calculate the concentration or physical properties of Therefore, when such a measuring device is installed in soil to measure the concentration or physical properties of the substance to be measured in the soil, it is conceivable that the measurement becomes unstable if the water content in the soil is low.

The present invention has been made in view of such circumstances, and its object is to provide a technique capable of stably measuring the concentration or physical properties of a substance to be measured in soil even when the water content is low. is.

The present invention adopts the following configurations in order to solve the above-described problems.

That is, a measuring device according to one aspect of the present invention includes a plurality of electrodes, at least a part of which is provided in soil, a sensor for detecting moisture, and a signal output from the sensor. a measuring unit that measures the potential of at least two of the plurality of electrodes and measures the concentration or physical properties of the substance to be measured contained in the soil based on the measured potential. .

According to this configuration, it is possible to detect moisture due to rainfall and apply a voltage between at least two of the plurality of electrodes. In such a case, the substance to be measured dissolved in the water falling on the soil moves between the electrodes. Therefore, the measured potentials of the two electrodes are values corresponding to the concentration of the substance to be measured. Therefore, it is possible to stably measure the concentration or physical properties of the substance to be measured even in soil with a low moisture content.

In the measuring device according to the above aspect, the plurality of electrodes has 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 may be the first electrode and the second electrode.

According to this configuration, it is possible to detect moisture due to rainfall and apply a voltage between the first electrode and the second electrode. In such a case, the substance to be measured dissolved in the water falling on the soil moves between the electrodes. Therefore, the measured potential of the first electrode and the potential of the second electrode are values corresponding to the concentration of the substance to be measured. Therefore, it is possible to stably measure the concentration or physical properties of the substance to be measured even in soil with a low moisture content.

In the measuring device according to the above aspect, the substance to be measured is moved in the direction in which the first electrode is present by applying a voltage between the first electrode and the second electrode. and a filter through which the substance to be measured can pass.

According to this configuration, it is possible to prevent sand and mud flowing with rain from coming into contact with the first electrode. Therefore, durability of the first electrode can be improved. Also, the influence of sand or mud adhering to the first electrode on the measurement accuracy is reduced.

The measuring device according to the one aspect described above may further include a power supply that supplies power to the measuring unit.

According to this configuration, the measuring device can operate without being connected to a power supply outside the measuring device. Therefore, even if the area of the soil is so large that it is difficult to connect to a power source outside the measuring device, it is possible to measure the concentration or physical properties of the substance to be measured.

In the measuring device according to the aspect described above, the plurality of electrodes may include a plurality of electrode sets each including a pair of electrodes.

According to this configuration, when the plurality of electrode sets are arranged at different depths inside the soil, the relationship between the temporal change in the concentration or physical properties of the substance to be measured and the depth in the soil can be obtained. Therefore, leaching of the substance to be measured from the soil due to environmental changes such as rainfall can be measured in detail.

In the measuring device according to the above aspect, the measuring section may change the potential measurement interval based on the signal output from the sensor.

According to this configuration, it is possible to drive the measuring device according to an event of environmental change such as rainfall, and measure the concentration or physical properties of the substance to be measured. Alternatively, the measurement frequency of the measurement device can be increased in response to environmental change events such as rainfall. Therefore, it is possible to measure the influence of environmental changes on the concentration or physical properties of the substance to be measured in soil. Also, if the configuration further includes a power supply, the power consumption of the power supply can also be reduced.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a technique capable of stably measuring the concentration or physical properties of a substance to be measured in soil even when the water content is low.

FIG. 1 illustrates an overview of a measuring device according to an embodiment. FIG. 2 illustrates an outline of a flow chart of the measurement operation of the measurement device according to the embodiment. FIG. 3 illustrates an outline of a measuring device according to a first modified example. FIG. 4 illustrates an outline of a flow chart of the measurement operation of the measurement device according to the first modification. FIG. 5 illustrates an outline of a measuring device according to a second modified example.

[Embodiment]
FIG. 1 illustrates an overview of a measuring device 1 according to this embodiment. FIG. 1A is an example of an external perspective view of the measuring device 1. FIG. FIG. 1B is an example of a side view of the measuring device 1. FIG. The measuring device 1 has a portable size and is arranged to be inserted into the soil 11 . Then, the concentration of the substance contained in the soil 11 that responds immediately to the growth of crops is measured. A substance that immediately responds to the growth of agricultural crops is, for example, nitrate nitrogen (an example of the “measurement target substance” of the present disclosure).

More specifically, the measurement device 1 has an electrode set consisting of a pair of working electrodes 2 and a reference electrode 3 . Therefore, part of the soil 11 exists between the working electrode 2 and the reference electrode 3 . Here, the water content of the soil 11 is less than 20%, for example. The working electrode 2 is a so-called ion-selective electrode, the surface of which is covered with a sensitive membrane. The sensitive film is a film capable of selectively trapping nitrate nitrogen. The sensitive film is, for example, a lacquer matrix liquid film or a PVC (polyvinyl chloride) matrix liquid film. The reference electrode 3 is, for example, a silver silver chloride electrode immersed in KCL (potassium chloride). In addition, the working electrode 2 is an example of the "first electrode" of the present disclosure. Moreover, the reference electrode 3 is an example of the "second electrode" of the present disclosure.

The measuring device 1 also has a measuring unit 4 . The measurement unit 4 is provided in the atmosphere outside the soil above the working electrode 2 and the reference electrode 3 . The measuring section 4 is electrically connected to the working electrode 2 and the reference electrode 3, respectively, and the connecting portions are protected by the case 5. As shown in FIG. The measuring unit 4 is also electrically connected to a power source outside the measuring device 1 (not shown). Incidentally, the diameter of the case 5 is, for example, 2 cm or less. Also, the measuring unit 4 is an example of the “measuring unit” of the present disclosure.

The measurement unit 4 is provided with a processor such as a CPU, a storage device such as a RAM and a ROM, and the like. Various programs and the like are stored in the storage device. Then, the stored program is loaded into the working area of the main memory and executed. Then, through execution of the program, a voltage is applied between the working electrode 2 and the reference electrode 3, the potentials of the working electrode 2 and the reference electrode 3 are measured, and the potential difference between the working electrode 2 and the reference electrode 3 is used as nitric acid. It is possible to realize each function that meets a predetermined purpose by controlling each component that performs the calculation of the nitrogen concentration.

The measuring device 1 also has a rain sensor 6 . The rain sensor 6 is, for example, an optical sensor. Moreover, the rain sensor 6 is provided on the measurement part 4 so that it may be exposed to the atmosphere. The rain sensor 6 is electrically connected to the measuring section 4 . The rain sensor 6 may be replaced by a sensor capable of detecting water by another method. The rain sensor 6 is an example of the "sensor" of the present disclosure.

[Example of operation]
Next, an outline of the measurement operation of the measurement device 1 will be illustrated. FIG. 2 illustrates an outline of a flow chart of the measurement operation of the measurement device 1. As shown in FIG.

(S01)
In step S<b>01 , the measurement unit 4 determines whether or not it is raining based on the output from the rain sensor 6 .

(S02)
In step S<b>02 , voltage is applied between the working electrode 2 and the reference electrode 3 when the measurement unit 4 determines in step S<b>01 that it is raining. The voltage is applied such that the working electrode 2 is the anode and the reference electrode 3 is the cathode. Then, since 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, it moves toward the working electrode 2, which is the anode. Nitrate nitrogen is captured by the sensitive film covering the outer surface of the working electrode 2 .

(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 the reference potential difference to calculate the concentration of nitrate nitrogen contained in the soil 11 relative to the reference concentration of nitrate nitrogen. 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.

[Action/effect]
According to the measuring device 1 as described above, the concentration of nitrate nitrogen can be measured in a state in which the amount of water in the soil 11 has increased by detecting moisture due to rainfall and starting to measure the concentration of nitrate nitrogen. becomes. The concentration of nitrate nitrogen can be stably measured even in soil 11 having a low volumetric water content. Therefore, the concentration of nitrate nitrogen can be precisely controlled in real time, and the yield and quality of agricultural products can be improved.

[Modification 1]
FIG. 3 illustrates an overview of a measuring device 1A according to a first modified example. A measuring device 1A according to the first modification has the same configuration as the measuring device 1 according to the embodiment. Furthermore, the measuring device 1 has an independent power supply 12 . The independent power source 12 is provided, for example, between the measuring section 4A and the rain sensor 6A. And the independent power supply 12 supplies electric power to the measurement part 4A and the rain sensor 6A.

The measuring device 1A also has a filter 7 covering the working electrode 2A. The filter 7 prevents sand, mud, etc. contained in the soil 11 from adhering to the working electrode 2A, while allowing nitrate nitrogen to pass through.

[Example of operation]
Next, an outline of the measurement operation of the measurement device 1A is illustrated. FIG. 4 exemplifies an outline of a flow chart of the measurement operation of the measurement device 1A.

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

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

(S3)
In step S3, if the measurement mode is determined to be the normal mode in step S2, the measurement unit 4A changes the measurement mode to the rain mode with short measurement intervals.

(S4)
In step S4, if the measurement mode is determined to be the rain mode in step S2, the measurement unit 4A maintains the rain mode as the measurement mode.

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

(S6)
In step S6, if the measurement mode is determined to be the normal mode in step S5, the measurement section 4A maintains the normal mode as the measurement mode.

(S7)
In step S7, if the measurement mode is determined to be the rain mode in step S5, the measurement unit 4A changes the measurement mode to the normal mode, which has a longer measurement interval and can suppress battery 12 consumption.

(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 in each measurement mode. The voltage is applied such that the working electrode 2A serves as an anode and the reference electrode 3A serves as a cathode. Then, nitrate nitrogen present between the working electrode 2A and the reference electrode 3A and bound to water moves toward the working electrode 2A. Nitrate nitrogen is captured by the sensitive film covering the outer surface of the working electrode 2A.

(S9)
In step S9, the measuring 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 calculates the concentration of nitrate nitrogen contained in the soil 11 relative to the reference concentration of nitrate nitrogen by comparing the calculated potential difference and the reference potential difference. 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.

[Action/effect]
According to the measuring apparatus 1A as described above, the measuring apparatus 1A can operate without being connected to a power supply outside the measuring apparatus 1A. Therefore, it is possible to measure the concentration of nitrate nitrogen even in a large area of soil 11 that has a low volumetric water content and is difficult to supply power from an external power source.

Further, according to the measuring device 1A as described above, when moisture due to rainfall or the like is detected, the frequency of nitrate nitrogen concentration measurement is increased, and conversely, when moisture is not detected, nitrate nitrogen concentration measurement is performed. reducing the frequency of Therefore, by adjusting the measurement interval of the measuring device 1A according to the event of environmental change such as rainfall, the power consumption of the independent power supply 12 can be reduced, and the event of environmental change such as rainfall can increase the concentration of nitrate nitrogen in the soil 11. You can measure the impact on

Moreover, according to the measuring device 1A as described above, the working electrode 2A is covered with the filter 7, thereby preventing sand and mud that flow with rain from coming into contact with the working electrode 2A. Therefore, the durability of the working electrode 2A can be improved. In addition, the influence of sand or mud adhering to the working electrode 2A on the measurement accuracy is reduced.

[Modification 2]
FIG. 5 illustrates an overview of a measuring device 1B according to a second modified example. A measuring device 1B according to the second modification has two electrode sets each including a pair of working electrode and a reference electrode. That is, the measuring 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 outside soil 11 in the middle of the depth direction. In addition, the working electrode 2C and the reference electrode 3C are arranged deeper in the soil 11 than the working electrode 2B and the reference electrode 3B.

[Action/effect]
According to the measuring device 1B as described above, by providing the working electrode 2B and the reference electrode 3B, and the working electrode 2C and the reference electrode 3C at different depths in the soil 11, the concentration of nitrate nitrogen changes with time and A relationship with depth in the soil 11 is obtained. Therefore, leaching of nitrate nitrogen from the soil 11 due to environmental change events such as rainfall can be measured in more detail.

[Other Modifications]
In the measuring device 1A according to the first modified example, the form of changing the frequency of concentration measurement of nitrate nitrogen when moisture due to rainfall or the like is detected is not limited to the example described above. For example, when moisture is not detected, the concentration of nitrate nitrogen may not be measured, and when moisture is detected, the concentration of nitrate nitrogen may be measured at predetermined intervals. Even with such a measuring device, it is possible to measure the influence of environmental change events such as rainfall on the nitrate nitrogen concentration and the like of the soil 11 while reducing the power consumption of the self-sustaining power supply 12 . Also, the measurement interval can be adjusted as appropriate.

Also, in the above embodiment, an example of measuring the concentration of nitrate nitrogen was shown, but the concentration of other substances may be measured. In such cases, the sensitive membrane is changed to a membrane that selectively traps other substances. Also, physical properties such as the diffusion coefficient of nitrate nitrogen may be measured using potential difference information between the working electrode 2 and the reference electrode 3 . Alternatively, the concentration or physical properties of nitrate nitrogen may be measured using only the potential information of the working electrode 2 . Moreover, the measuring device 1 does not have to be of a portable size.

The items described in the embodiments and modifications disclosed above can be combined.

1, 1A, 1B: measuring devices 2, 2A, 2B, 2C: working electrodes 3, 3A, 3B, 3C: reference electrodes 4, 4A: measuring units 5, 5B: cases 6, 6A: rain sensor 7: filter 11 : Soil 12 : Independent power source

Claims (6)

A measuring device comprising a sensor for detecting moisture,
a plurality of electrodes, at least a portion of the electrodes being provided in the soil;
a sensor for detecting moisture;
Based on the signal output from the sensor, the potential of at least any two of the plurality of electrodes is measured, and based on the measured potential, the concentration or physical properties of the substance to be measured contained in the soil. a measuring unit that measures
measuring device. The plurality of electrodes have an electrode set consisting of a pair of first electrode and 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. the substance to be measured moves in the direction in which the first electrode exists by applying a voltage between the first electrode and the second electrode;
Further comprising a filter provided to cover the first electrode and through which the substance to be measured can pass;
The measuring device according to claim 2. Further comprising a power supply that supplies power to the measurement unit,
The measuring device according to claim 2. The plurality of electrodes includes a plurality of electrode sets each consisting of a pair of electrodes,
The measuring device according to claim 2. The measurement unit changes the measurement interval of the potential based on the signal output from the sensor.
The measuring device according to claim 4.

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