Sensors

Abstract

To provide a sensor that can operate with an independent power source. [Solution] A sensor comprising a system including a first conductive portion and a second conductive portion, a medium, and a functional portion, wherein the first conductive portion and the functional portion are connected, the second conductive portion and the functional portion are connected, at least a portion of the first conductive portion and the second conductive portion are in contact with the medium, and the first conductive portion and the second conductive portion are not in contact with each other, and the sensor detects whether the internal impedance of the system satisfies a predetermined condition.

Description

[Technical field]

[0001] The present invention relates to a sensor that operates on an independent power source. [Background technology]

[0002] There are devices (i.e., batteries) that use two different metals as electrodes and are immersed in an electrolyte, causing an oxidation or reduction reaction at each electrode, creating a path for electrons to flow, such as a Voltaic cell or Daniell cell.

[0003] The liquid used as the electrolyte in the battery has the potential to have adverse effects on the human body and the environment, such as the risk of chemical burns, the risk of fire or explosion, or the generation of toxic gases, making it extremely difficult to handle the electrolyte. In addition, when commercializing the product, care must be taken to prevent leakage, which increases costs.

[0004] In recent years, energy harvesting technology, which converts minute energies such as visible light, heat, radio waves, or the decomposition of organic matter by microorganisms into electricity, has been attracting attention, and research is being conducted to put independent power sources into practical use using energy harvesting technology. Furthermore, in the IoT field, research is progressing on combining sensors with independent power sources to make it possible to obtain various information in various environments.

[0005] The use of solar power generation as an independent power source for devices such as sensors is being considered (see, for example, Patent Document 1), but it is easily affected by the time of day and weather, and may not provide a stable power supply. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-181278 A Summary of the Invention [Problem to be solved by the invention]

[0007] At least one object of the present invention is to provide a sensor that can operate from an independent power source. [Means for solving the problem]

[0008] According to the present invention, the above object can be achieved by [1] to

[14] . [1] A sensor including a system including a first conductive part and a second conductive part, a medium, and a functional part, the first conductive part and the functional part being connected, the second conductive part and the functional part being connected, at least a portion of the first conductive part and the second conductive part being in contact with the medium, and the first conductive part and the second conductive part being in non-contact with each other, the sensor detecting that an internal impedance of the system satisfies a predetermined condition; [2] A sensor including a system including a first conductive portion and a second conductive portion, a medium, and a functional portion, the first conductive portion and the functional portion being connected, the second conductive portion and the functional portion being connected, at least a portion of the first conductive portion and the second conductive portion being in contact with the medium, and the first conductive portion and the second conductive portion being in non-contact with each other, the sensor detecting when a predetermined voltage in the system satisfies a predetermined condition; [3] A sensor including a system comprising a first conductive part and a second conductive part, a medium, and a functional part, the first conductive part and the functional part being connected, the second conductive part and the functional part being connected, at least a part of the first conductive part and the second conductive part being in contact with the medium, and the first conductive part and the second conductive part being in non-contact with each other, the sensor detecting whether an amount of change per unit time of an internal impedance of the system satisfies a predetermined condition; [4] A sensor including a system including a first conductive portion and a second conductive portion, a medium, and a functional portion, the first conductive portion and the functional portion being connected, the second conductive portion and the functional portion being connected, at least a portion of the first conductive portion and the second conductive portion being in contact with the medium, and the first conductive portion and the second conductive portion being in non-contact with each other, the sensor detecting whether a change in a predetermined voltage in the system per unit time satisfies a predetermined condition; [5] The sensor according to any one of [1] to [4], wherein the functional unit includes a voltage step-up circuit or a voltage step-down circuit; [6] The sensor according to [2] or [4], wherein the functional unit includes a step-up circuit or a step-down circuit, and the predetermined voltage in the system is an input voltage or an output voltage of the step-up circuit or the step-down circuit; [7] The sensor according to any one of [1] to [6], wherein the functional unit has a conversion function for converting output impedance; [8] The sensor according to any one of [1] to [7], wherein the functional unit has a storage unit, and the storage unit has a function of storing electric charge supplied from the first conductive unit and / or the second conductive unit and discharging the stored electric charge in a time shorter than the time required for the storage; [9] The sensor according to any one of [1] to [8], wherein the functional unit has an output voltage conversion unit;

[10] The sensor according to any one of [1] to [9], wherein the input impedance of the functional unit has a nonlinear current-voltage characteristic;

[11] An apparatus for detecting whether an internal impedance of a system including a first conductive portion, a second conductive portion, and a functional portion, the first conductive portion and the functional portion being connected, the second conductive portion and the functional portion being connected, the first conductive portion and the second conductive portion being in non-contact with each other, and contacting a medium with the first conductive portion and the second conductive portion satisfies a predetermined condition;

[12] An apparatus comprising: a first conductive portion, a second conductive portion, and a functional portion, the first conductive portion and the functional portion being connected, the second conductive portion and the functional portion being connected, the first conductive portion and the second conductive portion being in non-contact with each other, and detecting that a predetermined voltage in a system configured by contacting a medium with the first conductive portion and the second conductive portion satisfies a predetermined condition;

[13] An apparatus for detecting whether a change per unit time in an internal impedance of a system including a first conductive portion, a second conductive portion, and a functional portion, the first conductive portion and the functional portion being connected, the second conductive portion and the functional portion being connected, the first conductive portion and the second conductive portion being in non-contact with each other, and a medium being brought into contact with the first conductive portion and the second conductive portion satisfies a predetermined condition;

[14] A device comprising a first conductive part, a second conductive part, and a functional part, the first conductive part and the functional part being connected, the second conductive part and the functional part being connected, the first conductive part and the second conductive part being non-contact with each other, and detecting whether a change per unit time of a specified voltage in a system configured by contacting a medium with the first conductive part and the second conductive part satisfies a specified condition. Effect of the Invention

[0009] According to the present invention, it is possible to provide a sensor that can operate with an independent power source. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a system configuration according to an embodiment of the present invention; [Diagram 2] 2 is a block diagram showing a configuration of a power conversion unit according to an embodiment of the present invention; FIG. [Diagram 3] FIG. 1 illustrates a system according to an embodiment of the present invention. [Figure 4] 1 is a diagram showing the relationship between time and current I when a transistor in a system is switched ON / OFF according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following description of the effects of the embodiment of the present invention is one aspect of the effects of the embodiment of the present invention, and is not limited to the description herein.

[0012] Fig. 1 is a block diagram showing a configuration of a system according to an embodiment of the present invention. As shown in Fig. 1(A) and (D), the system is composed of a first conductive part 1, a second conductive part 2, a functional part 3, and a medium 4. The first conductive part 1 and the functional part 3, and the functional part 3 and the second conductive part 2 are electrically connected to each other. "Electrically connected" means, for example, connected to be electrically conductive by a conductor or the like.

[0013] A part or the whole of the first conductive part 1 and the second conductive part 2 are in contact with the medium 4. The first conductive part 1 and the second conductive part 2 are not in contact with each other. "Non-contact" refers to, for example, a state in which the first conductive part 1 and the second conductive part 2 are not in direct contact with each other.

[0014] The distance between the position where the first conductive part 1 contacts the medium 4 and the position where the second conductive part 2 contacts the medium 4 is preferably 1 cm or more, more preferably 10 cm or more, even more preferably 100 cm or more, and particularly preferably 1000 cm (10 m) or more.

[0015] Both the first conductive part 1 and the second conductive part 2 are preferably conductive. Here, examples of materials for the first conductive part 1 and the second conductive part 2 include metals, conductive polymers, and carbon. The shapes of the first conductive part 1 and the second conductive part 2 are not particularly limited. The shapes of the first conductive part 1 and the second conductive part 2 may be rectangular parallelepiped, cylindrical (rod-like), pyramidal, conical, plate-like, or string-like, and are not limited to any particular shape.

[0016] The metal used for the first conductive portion 1 and the second conductive portion 2 can be appropriately selected from, for example, silver, copper, gold, aluminum, magnesium, zinc, nickel, platinum, tin, titanium, stainless steel, zinc oxide, magnesium oxide, or oxides of the above-mentioned metals. A predetermined metal may be coated with a metal different from the predetermined metal or a material having other conductivity.

[0017] The first conductive part 1 and the second conductive part 2 may be made of different materials or the same material. For example, a cylindrical stainless steel bar may be used for the first conductive part 1, and a cylindrical zinc bar may be used for the second conductive part 2. In this case, the first conductive part 1 and the second conductive part 2 are connected to the functional part 3 or the step-up circuit or step-down circuit by conductors.

[0018] When the polarization resistance of at least one of the first conductive section 1 and the second conductive section 2 is measured by an AC impedance method, the measured value is preferably 100Ω or more.

[0019] Here, the conductive part where the current starts is defined as the first conductive part 1, and the conductive part where the current ends is defined as the second conductive part 2. Which conductive part functions as the first conductive part 1 is determined by the material of the conductive part or the environment surrounding the conductive part (e.g., temperature, humidity, air pressure, pH, etc.). A chemical reaction takes place at the interface between the first conductive part 1 or the second conductive part 2 and the medium 4, generating free electrons in the conductive part.

[0020] For example, when different metals are used for the first conductive section 1 and the second conductive section 2, the one using the metal with a lower standard electrode potential becomes the first conductive section 1, and the one using the metal with a higher standard electrode potential becomes the second conductive section 2. In this case, electrons move from the second conductive section 2 to the functional section 3, and electrons move from the functional section 3 to the first conductive section 1. That is, a current is generated from the first conductive section 1 side to the second conductive section 2 side via the functional section 3. For example, in the second conductive section 2, the metal constituting the conductive section dissolves as cations into the medium 4, generating free electrons, and in the first conductive section 1, the cations in the water of the medium 4 react with the electrons to be electrically neutralized.

[0021] The level of standard electrode potential is determined by comparing the relative values ​​(relative values) of the standard electrode potentials of substances, not by comparing the absolute values ​​of the standard electrode potentials. For example, when comparing substance A with a standard electrode potential of -5 V and substance B with a standard electrode potential of +2 V, the standard electrode potential of substance A is low and the standard electrode potential of substance B is high.

[0022] On the other hand, even when the same metal is used for the conductive parts, depending on the conditions of the environment surrounding the conductive parts, such as temperature, humidity, air pressure, and pH, one of the conductive parts will function as the first conductive part 1 and the other conductive part will function as the second conductive part 2, generating a current. Therefore, if the conditions of the ambient temperature, humidity, air pressure, pH, etc. of the two conductive parts change, what has functioned as the first conductive part may start to function as the second conductive part, and what has functioned as the second conductive part may start to function as the first conductive part.

[0023] The electromotive force generated from the first conductive portion 1 and the second conductive portion 2 is preferably 0.9 V or less, more preferably 0.35 V or less, and even more preferably 0.25 V or less. In addition, the electromotive force generated from the first conductive portion 1 and the second conductive portion 2 is preferably 5 mV or more.

[0024] The functional unit 3 refers to, for example, a unit that executes a predetermined function by passing electricity through it. The functional unit 3 may include a power consumption unit that consumes power to perform a predetermined function, a power storage unit that stores electricity generated in a conductive unit, an output voltage conversion unit that converts the output voltage like a boost circuit or a step-down circuit, a control unit such as a microcomputer that controls the circuit, a communication unit that can wirelessly communicate with other devices, etc.

[0025] The power consumption unit may be, for example, a light source such as an incandescent light bulb or a light emitting diode, a heating element that generates heat, a sound generating element that generates sound, or a transmitter that generates a signal. The power storage unit may be included in a step-up circuit or a step-down circuit. A control unit such as a microcomputer controls the circuit to release the electricity stored in the power storage unit under predetermined conditions. The released electricity is consumed by the power consumption unit. In addition, the control unit such as a microcomputer also consumes power, albeit in a small amount, so that the stored electricity can be controlled to be released while ensuring the power required to start the control unit.

[0026] The functional unit 3 may include any one of a power consumption unit, a power storage unit, an output voltage conversion unit, a communication unit, and a control unit, and may be configured by combining any two or more of a power consumption unit, a power storage unit, an output voltage conversion unit, a communication unit, and a control unit. The functional unit 3 may be configured by integrally configuring any two or more of a power consumption unit, a power storage unit, an output voltage conversion unit, a communication unit, and a control unit, or may be configured by electrically connecting any one of a power consumption unit, a power storage unit, an output voltage conversion unit, a communication unit, and a control unit separately.

[0027] The input impedance of the functional unit 3 is preferably 1 kΩ or more, and more preferably 10 kΩ or more. The input impedance of the functional unit 3 preferably has a nonlinear current-voltage characteristic (IV characteristic). The nonlinear current-voltage characteristic refers to, for example, a case where, in a voltage change when a current is applied to the functional unit 3, the voltage value increases as the current value increases, but as the current value increases, the increase in the voltage value required to increase the current value increases, and the voltage is not proportional to the current. In other words, the current value increases as the voltage value applied to the functional unit 3 increases, but as the voltage value increases, the degree to which the current value increases by increasing the voltage value decreases, and the current value is not proportional to the voltage value. When the input impedance of the functional unit 3 has a nonlinear current-voltage characteristic, the electromotive force generated between the first conductive unit 1 and the second conductive unit 2 is easily maintained.

[0028] It is preferable that the functional unit 3 has a function of converting the output impedance, so that the influence of the functional unit 3 on the input signal can be controlled.

[0029] The functional unit 3 also has a power storage unit, which stores the charge supplied from the first conductive unit and / or the second conductive unit. The control unit controls the discharge of the stored charge in a shorter time than the time required to store the charge.

[0030] The lower limit of the operating voltage of the functional unit 3 is preferably 0.9 V or less, more preferably 0.35 V or less, and even more preferably 20 mV or less.

[0031] The medium 4 may be in any of the forms of gas, liquid, and solid. The medium 4 may be in the form of a sol or gel. The medium 4 is not particularly limited as long as it can cause a chemical reaction at the interface with the first conductive part 1 or the second conductive part 2. The medium 4 may contain an electrolyte. It is preferable to use a medium 4 that does not have electrical conductivity. The gas is not particularly limited as long as it is a gas when configuring the present system, and examples of the gas include oxygen, carbon dioxide, nitrogen, hydrogen, and methane. When a gas is used as the medium 4, only a single type of gas may be used, or a mixture of multiple types of these gases may be used.

[0032] The liquid used as the medium 4 is not particularly limited as long as it is liquid when configuring this system, but for example, not only water but also highly polar organic solvents, low polar organic solvents, or non-polar organic solvents can be used. The liquid used as the medium 4 can also be a mixture of water and a highly polar organic solvent, a mixture of two or more different organic solvents, or an emulsion. The water can be not only pure water but also water containing an electrolyte.

[0033] Of the electrolytes contained in the water, the concentration of cations may be 1 mol / L or less, 0.6 mol / L or less, 0.1 mol / L or less, 0.01 mol / L or less, 0.001 mol / L or less, or even 0.0001 mol / L or less.

[0034] Examples of organic solvents with high polarity include lower alcohols such as methanol and ethanol, lower carboxylic acids such as formic acid and acetic acid, acetone, tetrahydrofuran, and dimethyl sulfoxide. Examples of organic solvents with low polarity include higher alcohols such as hexanol and octanol, and higher carboxylic acids such as hexanoic acid and octanoic acid. Examples of non-polar organic solvents include aliphatic hydrocarbons such as hexane, octane, and nonane, and aromatic compounds such as benzene, toluene, and xylene. When a liquid is used as the medium 4, only a single type of liquid may be used, or a mixture of multiple types of these liquids may be used.

[0035] The solid used as the medium 4 is not particularly limited as long as it is solid when configuring the present system, and may be, for example, wood, metal, ceramics, concrete, etc. In addition to these, the solid used as the medium 4 may be, for example, a powdered or granular solid such as sand or soil, or a stack of multiple stones or rocks. When sand, soil, or stacked stones or rocks is used as the medium 4, minute voids are generated in the medium 4, but even if such voids exist, it is sufficient that the medium 4 is physically connected.

[0036] A single medium 4 can be constructed by physically connecting media 4 having different compositions and properties.

[0037] The resistance value between the first conductive portion 1 and the second conductive portion 2 of the medium 4 is preferably 1 kΩ or more, and more preferably 10 kΩ or more.

[0038] The medium 4 preferably contains moisture. The moisture content of the medium 4, such as sand or soil, is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. The moisture content of the medium 4 is preferably 200% by mass or less. Here, the moisture content refers to the weight of the moisture divided by the sum of the weight of the moisture and the solid content.

[0039] 1(A), a system according to an embodiment of the present invention is composed of a first conductive part 1, a second conductive part 2, a functional part 3, and a medium 4. The medium 4 is in contact with both the first conductive part 1 and the second conductive part, and the functional part 3 is electrically connected to the first conductive part 1 and the second conductive part 2.

[0040] In the system according to the embodiment of the present invention, as shown in FIG. 1(D), a plurality of first conductive portions 1a, 1b,...,1n (n is an integer of 2 or more) may be electrically connected in parallel. Also, a plurality of second conductive portions 2a, 2b,...,2m (m is an integer of 2 or more) may be electrically connected in parallel. Note that a plurality of first conductive portions 1a, 1b,...,1n may be electrically connected in series. Furthermore, a plurality of second conductive portions 2a, 2b,...,2m may be electrically connected in series.

[0041] 1(A) and 1(D) may be combined, but the combination is not limited as long as the effects of the present invention are achieved.

[0042] Fig. 2 is a block diagram showing a configuration of a power conversion unit according to an embodiment of the present invention. Fig. 2(A) is a circuit diagram of a boost circuit according to an embodiment of the present invention. The boost circuit or the step-down circuit is an example of a functional unit 3, and includes a power storage unit.

[0043] As shown in the figure, an inductor L, a diode D, a transistor Tr, and a capacitor C are electrically connected. For example, an input terminal A1 is connected to a first conductive unit 1, and an input terminal A2 is connected to a second conductive unit 2. An output terminal B1 and an output terminal B2 are connected to a power consumption unit, a control unit, and the like. The control unit may be connected between the boost circuit and the first conductive unit 1 and the second conductive unit 2 so as to be in parallel with the boost circuit.

[0044] When the transistor Tr is ON, the input voltage V IN When the input voltage V is applied, electrical energy is stored in the inductor L. INis the potential difference between the connection points P1 and P2. When the transistor Tr is OFF, the input voltage V IN The electrical energy from is added to the energy stored in inductor L and output through diode D. As a result, the input voltage V IN The output voltage V OUT The boost circuit operates on the input voltage V IN The input voltage V of the boost circuit is assumed to be lower than a predetermined voltage, and the boost control may not be performed at a voltage higher than the predetermined voltage. IN is preferably 5 mV or more. The ON / OFF of the transistor Tr is controlled by a control unit.

[0045] 2(B) is a circuit diagram of a step-down circuit according to an embodiment of the present invention. As shown in the figure, a transistor Tr, an inductor L, a diode D, and a capacitor C are electrically connected. For example, an input terminal A1 is connected to a first conductive unit 1, and an input terminal A2 is connected to a second conductive unit 2. An output terminal B1 and an output terminal B2 are connected to a power consumption unit, a control unit, and the like. Note that the control unit may be connected between the step-down circuit and the first conductive unit 1 and the second conductive unit 2 so as to be in parallel with the step-down circuit.

[0046] When the transistor Tr is ON, electrical energy is stored in the inductor L. The input voltage V IN is the connection point P 11 and connection point P 12 is the potential difference between the output voltage V OUT is the connection point P 13 and connection point P 14 In this case, the input voltage V IN is the output voltage V OUT When the transistor Tr is turned off, the connection point P 15 The potential at the connection point P 14 Since the potential of the output voltage V OUT The step-down circuit operates by reducing the input voltage V INis higher than a predetermined voltage, and the step-down control may not be performed at a voltage lower than the predetermined voltage. The ON / OFF of the transistor Tr is controlled by the control unit.

[0047] Next, a method for measuring the internal impedance of the system of the present invention will be described. Fig. 3 is a diagram showing a system according to an embodiment of the present invention. The potential difference between the first conductive part 1 and the second conductive part 2 is V 1 IN The potential difference between connection point P1 and connection point P2 is defined as V 2 IN The potential difference between the connection points P5 and P6 can be defined as V 1 OUT The potential difference between the connection points P3 and P4 is defined as V 2 OUT When power is generated by the system of the present invention, an electromotive force V 1 IN This causes a current I to flow in the direction between connection point P1 and connection point P5.

[0048] 3, the first conductive unit 1 is connected to a boost circuit at a connection point P1, and the second conductive unit 2 is connected to a connection point P2. In the boost circuit, an inductor L, a diode D, a transistor Tr, and a capacitor C are electrically connected.

[0049] FIG. 4 is a diagram showing the relationship between time and current I when a transistor in a system is switched ON / OFF according to an embodiment of the present invention. Here, V 1 OUT and V 2 IN The relationship between the current I flowing through the inductor L and the inductance L1 is expressed as follows: 1 OUT -V 2 IN When the transistor Tr is ON, V 1 OUT = 0, so equation (2): V 2IN = L1 × dI / dt. In this case, dI / dt is a positive value, and the current I increases with time. On the other hand, when the transistor Tr is OFF, V 1 OUT >V 2 IN Therefore, equation (1):V 1 OUT -V 2 IN =-L1×dI / dt, we can see that dI / dt is a negative value. In this case, the current I decreases over time. The transistor Tr is periodically turned on and off.

[0050] Here, if the first conductive part 1, the second conductive part 2, and the medium 4 are regarded as a type of battery, the electromotive force V 1 IN In this case, if the internal impedance caused by the medium 4 is defined as Z, the relationship between the input voltage and the internal impedance is given by equation (3): 1 IN =Z×I+V 2 IN It can be expressed as:

[0051] In addition, while the transistor Tr is OFF (hereinafter, T OFF During this period, a current I charges a capacitor C with a charge Q. OFF During this period, if the voltage increase at the connection point P3 is ΔV and the capacitance of the capacitor C is C1, then equation (4): Q=∫Idt=C1×ΔV holds.

[0052] From equations (2) and (3), V 1 IN = L1 × dI / dt + Z × I. By solving this equation, with A as the integral constant, we obtain equation (5): I(t) = V 1 IN / Z+A×e (-Z / L1×t)If the time when the transistor Tr switches from OFF to ON is t=0, as is clear from FIG. 4, the current I is zero at t=0. Therefore, by substituting t=0 and I=0 into equation (5), we obtain A=-V 1 IN / Z relationship holds. This A=-V 1 IN Substituting / Z into equation (5), we get equation (6): I(t) = V 1 IN / Z×(1-e (-Z / L1×t) ) can be derived. on The current I during this period (called the ON period) can be calculated using equation (6). If the transistor Tr is turned on for a sufficient period, the maximum value of the current I is V 1 IN / Z.

[0053] T on The period ends and T off The current I at the start of the period (i.e., when the time T1 has elapsed since the transistor Tr was switched from OFF to ON) can be calculated by substituting t=T1 into equation (6). This is because, as can be seen from FIG. 4, the current I has continuity. (1-e (-Z / L1×T1) ) = K (constant), the current I at t = T1 is I(T1) = V 1 IN / Z×(1-e (-Z / L1×T1) )=K×V 1 IN / Z. Note that K satisfies the relationship 0≦K<1, and when the value of Z / L1×T1 becomes sufficiently large, K can approximate 1.

[0054] Next, using equations (1) and (3), we obtain equation (7): L1×dI / dt+Z×I=V 1 IN -V 1 OUT Furthermore, from equation (4), V 2 OUT is ∫Idt / C1+V start Here, Vstart is T off is the voltage across the capacitor C at the beginning of the period (t=T1) and is a constant. The threshold voltage of the diode D is V f Then, equation (8):V 1 OUT =V 2 OUT +V f =∫Idt / C1+V start +V f =∫Idt / C1+V´ out Here, we can derive V' out =V start +V f is a constant.

[0055] Furthermore, from equations (7) and (8), equation (9): ∫Idt / C1+Z×I+L1×dI / dt=V 1 IN -V´ out By solving the differential equation (9), T off The current I during the period t is expressed as the capacitance of the capacitor C1, the internal impedance Z, the inductance L1, and the V 1 IN , V´ out , K. T off If the start time of the period is t=0, the initial value I(0) of the current I at that time is I(0)=K×V 1 IN / Z. off When the period ends (that is, when the time T2 has elapsed since the transistor Tr was switched from ON to OFF and the current I became zero), I(T2) = 0. The capacitance of the capacitor C1, the inductance L1, and V' out is a constant, and if I(0) and T2 are measured, V 1 IN and Z values ​​can be calculated respectively.

[0056] Z can be calculated in a simple way, unlike the method described above. off During this period, V 1 OUT V 2 INSince the voltage is about 10 times larger than that of V, dI / dt is also large. In this case, ∫Idt in equation (4) corresponds to the area of ​​triangle S in Figure 4. Therefore, from equation (4), we obtain equation (9): ∫Idt = K × V 1 IN / Z×T2 / 2=C1×ΔV. Here, T on If the time is long enough, K can be approximated as ≒ 1. Therefore, by substituting K = 1 into equation (9), we obtain equation (10):V 1 IN / Z×T2 / 2=C1×ΔV is derived. C1 is a constant, and T off ΔV, T at the point when the period is long enough (when the current I is at its minimum value) off V at the point when the period is long enough (when the current I reaches its minimum value) 1 IN , T2(V 1 OUT V 2 IN Z can be calculated from the time when the temperature becomes equal to T off After a sufficiently long period of time (when current I has been consumed), V 1 IN =V 2 IN Therefore, V 2 IN By measuring V 1 IN can be identified.

[0057] The internal impedance Z is calculated by the control unit.

[0058] (First embodiment of the sensor) The sensor according to the first embodiment of the present invention is a sensor utilizing the above-mentioned system. IN Or the output voltage V OUT Here, the predetermined condition is the internal impedance Z or the input voltage V IN Or the output voltage V OUTThe input voltage V that is the subject of a predetermined condition can be appropriately designed so that it exceeds a predetermined threshold, is equal to or greater than a predetermined threshold, is smaller than a predetermined threshold, or is equal to or less than a predetermined threshold. IN For example, T off Take a sufficiently long period and measure the input voltage V at the point when the current I becomes zero. 2 IN and the output voltage V OUT For example, T off Take a sufficiently long period and measure the output voltage V when the current I becomes zero. 2 OUT Also, the input voltage V IN For example, T off The input voltage V at the start of the period 2 IN and the output voltage V OUT For example, T off The output voltage V at the start of the period 2 OUT T off The input voltage V when the period begins 2 IN As is clear from equation (3), the value depends on the impedance Z. Conversely, this input voltage V 2 IN By measuring the impedance Z, it is possible to grasp the fluctuation of the input voltage. off The input voltage V when the period begins 2 IN is valid as measurement data. Internal impedance Z or input voltage V IN Or the output voltage V OUT If the predetermined condition is satisfied, a signal is sent from the communication unit to another computer device under the control of the control unit.

[0059] For example, the sensor of the present invention can be used with water from a river, a pond, the sea, a dam, or the like as a medium. The sensor is installed so that the longitudinal direction of the first conductive part 1 and the second conductive part 2 is perpendicular to the water surface. As the height of the water surface changes, the internal impedance or the input voltage V INOr the output voltage V OUT However, when a predetermined condition is satisfied, a signal is sent to the other computer device. When the other computer device receives the signal, information notifying that the water surface height has exceeded a threshold is displayed on the display screen of the other computer device, or is output as a voice by the other computer device. In this way, by using the sensor of the present invention, it becomes possible for the other computer device to grasp that the water surface height has risen and that danger is approaching around the installation position of the sensor.

[0060] In the first embodiment, the sensor detects the change in the water surface height. However, even if there is a change in the water quality (pH or composition) at the installation position of the sensor, the internal impedance or input voltage V IN Or the output voltage V OUT In the first embodiment, the use of water from a river, a pond, the sea, a dam, or the like as a medium has been described, but the sensor of the present invention can also use something other than water, such as soil, as a medium.

[0061] (Second embodiment of the sensor) The sensor according to the second embodiment of the present invention is a sensor utilizing the above-mentioned system. IN Or the output voltage V OUT A sensor that detects whether the change in the input voltage V per unit time satisfies a certain condition. IN Or the output voltage V OUT The change amount per unit time of the internal impedance or input voltage V can be appropriately designed to exceed a predetermined threshold, be equal to or greater than a predetermined threshold, be smaller than a predetermined threshold, or be equal to or less than a predetermined threshold. IN Or the output voltage V OUT When the amount of change per unit time satisfies a predetermined condition, a signal is sent from the communication unit to another computer device under the control of the control unit.

[0062] For example, the sensor of the present invention can be used with water from a river, a pond, the sea, a dam, or the like as a medium. The sensor is installed so that the longitudinal direction of the first conductive part 1 and the second conductive part 2 is perpendicular to the water surface. As the height of the water surface changes, the internal impedance or the input voltage V IN Or the output voltage V OUT When the amount of change per unit time of satisfies a predetermined condition, a signal is sent to the other computer device. When the other computer device receives the signal, information notifying that the water surface height has suddenly risen (or that the water surface height has suddenly dropped) is displayed on the display screen of the other computer device, or is output as sound by the other computer device. In this way, by using the sensor of the present invention, it becomes possible for the other computer device to grasp that the water surface height has suddenly risen and that danger is approaching around the installation position of the sensor.

[0063] In the second embodiment, the use of water from a river, pond, ocean, dam, etc. as the medium was described, but the sensor of the present invention can also use something other than water, such as soil, as the medium.

[0064] In the embodiments of the present invention, a "system" refers to, for example, a system including elements necessary to achieve the effects of the present invention. More specifically, the system also includes circuits and devices. A "conductive part" may be, for example, a conductive member, and may be made of any material. A "functional part" refers, for example, to a part that performs a predetermined function by passing a current through it. The function may be to convert electricity into energy such as light or heat, or to control a circuit.

[0065] In the embodiment of the present invention, the term "electrolyte" refers to, for example, an electrically conductive solution obtained by dissolving an ionic substance in a polar solvent. The term "boosting circuit" refers to, for example, a circuit that boosts an input voltage and outputs it. The term "step-down circuit" refers to, for example, a circuit that steps down an input voltage and outputs it. The term "conductive polymer" refers to, for example, a polymeric compound that has electrical conductivity. The term "carbon" refers to, for example, carbon fiber that has electrical conductivity. The term "integrally constituted" refers to, for example, joining different objects together, and more specifically, examples of joining by chemical and / or physical forces include adhesion with an adhesive, mechanical joining using other members, welding, crimping, etc.

[0066] [Example] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0067] Example 1 The following tests were performed at room temperature and normal pressure. A circuit including a first conductive part 1, a second conductive part 2, a functional part 3, and a medium 4, as shown in FIG. 1(A), was used. A plate-shaped member (0.5 mm thick, 10 cm x 15 cm) made of stainless steel (austenitic, SUS304 series) was used as the first conductive part 1, and a plate-shaped member (0.5 mm thick, 10 cm x 15 cm) made of galvanized steel sheet (iron) was used as the second conductive part 2, and the first conductive part 1, the second conductive part 2, and the functional part 3 were each connected with a copper conductor. The functional part 3 includes a power consumption part, an output voltage conversion part, a communication part, and a control part. In addition, the input impedance of the functional part 3 was 1 kΩ or more, and the functional part 3 had a nonlinear current-voltage characteristic. The power consumption part was an LED light bulb that lights up when a current of 2 mA or more flows. The output voltage conversion part was a boost circuit as shown in FIG. 2(A), and the system was configured.

[0068] The first conductive part 1 was connected to the input terminal A1 of the boost circuit of the output voltage conversion part, and the output terminal B1 of the boost circuit was connected to the LED bulb. Furthermore, the second conductive part 2 was connected to the input terminal A2 of the boost circuit, and the output terminal B2 of the boost circuit was connected to the terminal opposite to the terminal connected to the output terminal B1 of the LED bulb.

[0069] A system was constructed by pouring pure water (high-purity purified water, temperature 25°C: medium 4, manufactured by Furukawa Chemical Industries Co., Ltd.) to a height of 7.5 cm into an acrylic container (cube with outer diameter 15 cm x 15 cm x 15 cm, inner diameter 14.5 cm) and immersing the first conductive part 1 and the second conductive part 2. The first conductive part 1 and the second conductive part 2 were not in contact with each other, the distance between the first conductive part 1 and the second conductive part 2 was 12 cm, and the first conductive part 1 and the second conductive part 2 were installed so that their plate-like flat surfaces were parallel to each other.

[0070] The voltage between the first conductive part 1 and the second conductive part 2 of the constructed system was measured (measurement 1). For the measurement, an Agilent Technologies 34401A multimeter was used. The results are shown in Table 1. In the system shown in Example 1, the LED bulb repeatedly blinked every 270 to 330 seconds. In other words, it was confirmed that electricity was generated from the first conductive part 1 and / or the second conductive part 2.

[0071] Next, the first conductive part 1 and the second conductive part 2 were immersed in pure water (high-purity purified water, temperature 25 degrees: medium 4, manufactured by Furukawa Chemical Industries Co., Ltd.) to a height of 7.5 cm in an acrylic container (cube with outer diameter 15 cm x 15 cm x 15 cm, inner diameter 14.5 cm), and the first conductive part 1 and the second conductive part 2 were immersed in the pure water. The first conductive part 1 and the second conductive part 2 were not in contact with each other, the distance between the first conductive part 1 and the second conductive part 2 was 12 cm, and the plate-like planes of the first conductive part 1 and the second conductive part 2 were installed so as to be parallel. In addition, the first conductive part 1 and the second conductive part 2 were not electrically connected to each other. Then, the voltage between the first conductive part 1 and the second conductive part 2 was measured using a 34401A multimeter (measurement 2). Furthermore, in this state, the resistance value of the medium 4 between the first conductive part 1 and the second conductive part 2 was measured (measurement 3).

[0072] Example 2 Measurements 1 to 3 were carried out in the same manner as in Example 1, except that the medium 4 was changed to soil (Prothleaf Corporation, soil for foliage plants). The results are shown in Table 1. In the system shown in Example 2, the LED bulb repeatedly blinked at approximately equal intervals of 21 to 23 seconds. In other words, it was confirmed that electricity was generated from the first conductive part 1 and / or the second conductive part 2.

[0073] Example 3 Measurements 1 to 3 were carried out in the same manner as in Example 1, except that a cloth soaked in an aqueous solution of 5 g of salt (Hakata Salt, manufactured by Hakata Salt Co., Ltd.) dissolved in 50 g of pure water (the same as in Example 1) was attached to the surfaces of the first conductive part 1 and the second conductive part 2 that come into contact with the medium 4, and the medium 4 was changed to sand (silica sand manufactured by Toyo Materan Co., Ltd., with a grain size peak (weight ratio) of about 0.9 mm). The results are shown in Table 1. In the system shown in Example 2, the LED bulb repeatedly blinked every 80 to 100 seconds. In other words, it was confirmed that electricity was generated from the first conductive part 1 and / or the second conductive part 2.

[0074] [Table 1]

[0075] Example 4 In Example 1, pure water was poured into the acrylic container up to a height of 7.5 cm, and pure water was added to the container up to a height of 10 cm. By adding pure water, the change in the internal impedance of the system described above was confirmed. In addition, by adding pure water, T off The input voltage V when the period begins 2 IN The change in internal impedance was calculated using the method described above.

[0076] Example 5 In Example 1, pure water was poured into the acrylic container up to a height of 7.5 cm, and pure water was then added over a period of 5 minutes up to a height of 10 cm. It was confirmed that the amount of change per unit time in the internal impedance of the above-mentioned system changed. It was also confirmed that the amount of change per unit time in the input voltage changed as pure water was added. The internal impedance was calculated using the calculation method described above. The input voltage was T off The input voltage V when the period begins 2 IN It is. [Explanation of symbols]

[0077] 1 first conductive part, 2 second conductive part, 3 functional part, 4 medium, 5 insulating part

Claims

1. A first conductive portion and a second conductive portion; The media and Functional section and Equipped with the first conductive portion and the functional portion are connected to each other, the second conductive portion and the functional portion are connected to each other, At least a portion of the first conductive portion and the second conductive portion contacts the medium; the first conductive portion and the second conductive portion are not in contact with each other, the first conductive portion and the second conductive portion are made of different materials, the medium is water containing an electrolyte having a cation concentration of 0.01 mol / L or less, sand or soil containing moisture, or concrete; A sensor comprising a system for generating electricity by contacting at least a portion of a first conductive portion and a second conductive portion with the medium, A sensor that detects when a certain voltage in a system meets a certain condition.

2. The sensor according to claim 1 , wherein the functional unit comprises a voltage step-up circuit or a voltage step-down circuit.

3. The functional unit includes a step-up circuit or a step-down circuit, 3. The sensor according to claim 1, wherein the predetermined voltage in the system is an input voltage or an output voltage of a step-up circuit or a step-down circuit.

4. The sensor according to any one of claims 1 to 3, wherein the functional portion has a conversion function for converting output impedance.

5. The functional unit has a power storage unit, the charge storage section stores the charge supplied from the first conductive section and / or the second conductive section; 5. The sensor according to claim 1, having a function of discharging the accumulated charge in a shorter time than the time required for the accumulation.

6. The sensor according to any one of claims 1 to 5, wherein the functional portion has an output voltage conversion portion.

7. 7. The sensor according to claim 1, wherein the input impedance of the functional part has a nonlinear current-voltage characteristic.

8. The sensor according to any one of claims 1 to 7, wherein the medium is soil containing moisture.

9. The functional unit has a communication unit, The sensor according to any one of claims 1 to 8, wherein the communication unit has a function of transmitting a signal to another computer device when the sensor detects that a predetermined voltage in the system satisfies a predetermined condition.

10. A first conductive portion and a second conductive portion; Functional section and Equipped with the first conductive portion and the functional portion are connected to each other, the second conductive portion and the functional portion are connected to each other, the first conductive portion and the second conductive portion are not in contact with each other, the first conductive portion and the second conductive portion are made of different materials, The method includes contacting a medium with the first conductive part and the second conductive part, and detecting whether a predetermined voltage in the power generating system satisfies a predetermined condition; An apparatus, wherein the medium is water containing an electrolyte having a cation concentration of 0.01 mol / L or less, sand or soil containing moisture, or concrete.

11. A first conductive portion and a second conductive portion; The media and Functional section and Equipped with the first conductive portion and the functional portion are connected to each other, the second conductive portion and the functional portion are connected to each other, At least a portion of the first conductive portion and the second conductive portion contacts the medium; the first conductive portion and the second conductive portion are not in contact with each other, the first conductive portion and the second conductive portion are made of different materials, the medium is water containing an electrolyte having a cation concentration of 0.01 mol / L or less, sand or soil containing moisture, or concrete; The method includes detecting whether a predetermined voltage in a system generated by contacting at least a portion of a first conductive portion and a second conductive portion with the medium satisfies a predetermined condition.

Images