Terminal device and program

Abstract

To provide a terminal device in a network such as an IoT in a form that allows the efficient use of a solar battery.SOLUTION: Disclosed is a terminal device 20 in a network which is configured so as to work (21) with electric power obtained from a solar battery 10. The device monitors (22) output voltage obtained from the solar battery 10 and executes first processing in which, after intervals of data transmission onto the network are adjusted (28) so as to maintain the output voltage in the vicinity of the maximum operation voltage point of the solar battery, the data transmission (29) is executed.SELECTED DRAWING: Figure 3

Description

【Technical Field】 【0001】 The present invention relates to a terminal device and a program in a network such as IoT. 【Background Art】 【0002】 In order to efficiently obtain power generated from a solar cell, it is generally performed to use a dedicated MPPT (Maximum Power Point Tracking) control charge controller that charges the battery while finding the maximum power point of the solar cell using a hill climbing method or the like. FIG. 1 is a diagram illustrating the characteristics of a solar cell. As shown on the upper side, a current characteristic (I-V characteristic) as a function of an input voltage and a power characteristic (P-V characteristic) as a function of an input voltage exist in various states of the solar cell as shown on the lower side. 【0003】 In the system disclosed in Patent Document 1 (the name of the invention is "Photovoltaic power generation system and its control method"), by preparing in advance, as a database, the operating voltage of the solar cell corresponding to the solar radiation amount to the solar cell or the temperature of the solar cell as the state of the solar cell, the MPPT control can be omitted. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Laid-Open No. 2000-181555 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, in the prior art, in relation to a terminal used in a network such as IoT (Internet of Things), effectively using a solar cell has not been considered. 【0006】 In other words, as shown in Figure 2, an example of a conventional system configuration, where charging from solar panels to a rechargeable battery is controlled by an MPPT device and this battery is used as the power source for an IoT terminal, MPPT devices generally consume a lot of power, and there are no small-scale, low-power models available, making installation for IoT terminals difficult. In addition, the operation of the MPPT device itself consumes power from the solar panels, and there are also equipment costs associated with installing the MPPT device itself. 【0007】 Furthermore, while the method described in Patent Document 1 allows for the omission of an MPPT device by utilizing a pre-built database, it did not consider how to efficiently operate solar cells in relation to terminals within a network such as IoT. 【0008】 In view of the problems of the above-mentioned conventional technology, the present invention aims to provide a terminal device and program for IoT and other networks that can efficiently utilize solar cells. [Means for solving the problem] 【0009】 To achieve the above objective, the present invention provides a terminal device for a network, configured to operate using power obtained from a solar cell, and characterized in that it monitors the output voltage obtained from the solar cell, adjusts the interval for transmitting data to the network so as to maintain the output voltage near the maximum operating voltage point of the solar cell, and then performs a first process of transmitting the data. The present invention is also characterized in that it is a program corresponding to the terminal device. [Effects of the Invention] 【0010】 According to the present invention, by transmitting data at intervals that maintain the output voltage near the maximum operating voltage point of the solar cell, it becomes possible to efficiently utilize solar cells in terminal devices within a network. [Brief explanation of the drawing] 【0011】 [Figure 1] This is a diagram illustrating the characteristics of a solar cell. [Figure 2] This figure shows an example of a conventional system configuration. [Figure 3] This diagram shows the configuration of an IoT system according to one embodiment, and the functional blocks of each component. [Figure 4] Figure 3 is a schematic diagram illustrating the configuration of the IoT system. [Figure 5] This is a flowchart illustrating the operation of a terminal device according to one embodiment. [Figure 6] This figure shows a schematic example of the behavior of the output voltage of a solar cell, as realized by the flow shown in Figure 5. [Figure 7] This figure shows a schematic example of the behavior of the output voltage of a solar cell realized by the second embodiment, which is a modified version of the first embodiment shown in Figure 5. [Figure 8] This figure shows a schematic example of the effects according to an embodiment of the present invention, compared to a schematic example of proportionality when the present invention is not applied. [Figure 9] This is a flowchart illustrating the operation (case distinctions) of the terminal device according to the third embodiment. [Figure 10] This figure shows an example of a typical computer hardware configuration. [Modes for carrying out the invention] 【0012】 Figure 3 is a diagram showing the configuration of an IoT system 100 according to one embodiment and the functional blocks of each component, and Figure 4 is a diagram schematically showing the configuration of the IoT system in Figure 3. As shown in Figure 3, the IoT system 100 comprises a solar cell system 10 including a power generation unit 11 and an output unit 12, a terminal device 20 including a receiving unit 21, an output voltage monitoring unit 22, a power storage unit 23, an environmental information acquisition unit 24 including a solar irradiance acquisition unit 25 and a temperature acquisition unit 26, a control unit 27 including a planning unit 28 and an IoT function unit 29, and a separate device 40. 【0013】 In one example, both terminal device 20 and other device 40 are configured as any single IoT terminal within the IoT network NW. In one example, the IoT network NW can be configured as a known ad-hoc network using BLE (Bluetooth® Low Energy) technology, etc., and in the absence of base stations or fixed networks, when each IoT terminal such as terminal device 20 or other device 40 sends data to a destination terminal that is beyond the range of its own radio waves, it can search for a relay terminal and transmit the data to the destination terminal in a bucket brigade manner via that relay terminal. In another example, the IoT network NW can also be configured as any other network configuration not limited to an ad-hoc network, such as wireless LAN, LPWA (Low Power Wide Area), 5G, etc., and it is also possible to configure it so that terminal device 20 can access a data server that manages IoT network data etc. via a base station. In the case of an ad-hoc network, other device 40 may be another terminal device that terminal device 20 accesses via short-range communication such as Bluetooth®, or it may be a base station that terminal device 20 accesses in the case of a wireless LAN or other network. Furthermore, the network NW may be any network whose use is not limited to IoT, but in the following explanation, it will be described as an IoT network NW or IoT system 100 as an example. 【0014】 The power generation unit 11 is configured as a solar cell panel (and its peripheral circuitry) and outputs power generated from ambient light to the output unit 12. The output unit 12 is configured as a power transmission circuit and constantly transmits the power generated by the power generation unit 11 to the receiving unit 21 of the terminal device 20. 【0015】 The receiving unit 21 is configured as a power receiving circuit and a power supply circuit for each circuit of the terminal device 20 and other hardware, and supplies the generated power of the solar cell obtained from the output unit 12 to the power storage unit 23, the control unit 27, and the environment information acquisition unit 24. The power supply process by the receiving unit 21 can be implemented according to the plan obtained from the planning unit 28. When the control unit 27 is in a stopped state and the plan from the planning unit 28 cannot be used, power supply may be performed according to a predetermined rule, such as supplying power from the receiving unit 21 when the power storage unit 23 can store power. 【0016】 Also, in the receiving unit 21, when obtaining the generated power of the solar cell from the output unit 12, after setting the output unit 12 to output at the maximum operating voltage Vmax so as to receive the power as close as possible to the maximum operating voltage Vmax, the power is received. The setting of the maximum operating voltage Vmax can receive a set value in the receiving unit 21 based on the illuminance at that time from the planning unit 28 and set the output unit 12 to output at the maximum operating voltage Vmax. 【0017】 The output voltage monitoring unit 22 constantly monitors the voltage obtained from the output unit 12 (corresponding to the generated voltage of the solar cell) and outputs the result to the planning unit 28. The power storage unit 23 is configured as a secondary battery such as a lithium ion battery (and its peripheral circuit), stores (charges) power by the power obtained from the receiving unit 21, and supplies the stored power as the operating power for each part of the terminal device 20. The power storage process and / or the power supply process in the power storage unit 23 can be executed according to the plan obtained from the planning unit 28. 【0018】 The environmental information acquisition unit 24 periodically acquires the environmental information of the environment where the photovoltaic power generation equipment 10 is arranged, and outputs this environmental information to the planning unit 28. The sunshine amount acquisition unit 25 acquires the measurement result of a sunshine sensor arranged near the photovoltaic power generation equipment 10, or acquires the weather information of the location where the photovoltaic power generation equipment 10 is arranged from a separate weather information management server etc. on the network, thereby acquiring the information on the sunshine amount in the environment of the photovoltaic power generation equipment 10 as being included in the environmental information. The temperature acquisition unit 26 acquires the measurement result of a temperature sensor arranged near the photovoltaic power generation equipment 10, or acquires the temperature information (ambient temperature) of the location where the photovoltaic power generation equipment 10 is arranged from a separate weather information management server etc. on the network, thereby acquiring the information on the temperature in the environment of the photovoltaic power generation equipment 10 as being included in the environmental information. 【0019】 Based on at least a part of the output voltage of the photovoltaic cell monitored by the output voltage monitoring unit 22, the voltage of the secondary battery of the power storage unit 23 (a voltage that can be associated with the remaining charge amount of the secondary battery by referring to a predetermined map), and the environmental information acquired from the environmental information acquisition unit 24, the planning unit 28 formulates an operation plan for the terminal device 20, and operates the terminal device 20 in accordance with the operation plan. 【0020】 The targets planned by the planning unit 28 include the following (referred to as plans PL1 and PL2). ● Plan PL1... Setting of the transmission and reception frequency by the IoT function unit 29 as one of the specific processing contents of the control unit 27 (a processor such as a CPU). ● Plan PL2... How to allocate the electric power of the photovoltaic cell received by the reception unit 21 to the power storage of the power storage unit 23 (secondary battery), the processing of the control unit 27 (a processor such as a CPU), etc. 【0021】 The planning unit 28 also compares the illuminance and / or temperature in the environmental information acquired from the environmental information acquisition unit 24 with a predetermined map to determine the maximum power point of the solar cell (the point where the power P in the IV characteristic or PV characteristic in Figure 1 is maximum) when placed at that illuminance and / or temperature. The planning unit 28 notifies the receiving unit 21 of the maximum operating voltage Vmax corresponding to this maximum power point, and the planning PL1 and PL2 above enable the receiving unit 21 to set the output unit 12 to output generated power near this maximum operating voltage Vmax (as much as possible). 【0022】 Thus, the output unit 12 operates to output the maximum power Pmax at the maximum power point (maximum operating voltage Vmax, maximum power Pmax, and corresponding current I = Pmax / Vmax) corresponding to the illuminance and / or temperature where the solar cell is placed. If the receiving unit 21 receives this maximum power Pmax and the terminal device 20 continues to consume it all, a balanced state of supply and consumption of the maximum power Pmax will be maintained stably. On the other hand, in individual situations depending on the operation of the terminal device 20 and the illuminance, for example, when transmitting data, more power than the maximum power Pmax is consumed, and when in standby mode without transmitting data, less power consumption than the maximum power Pmax is sufficient. In such cases, the power output of the solar cell and the power reception by the receiving unit 21 will deviate somewhat from the maximum operating point set in the output unit 12. However, as will be explained in detail below, the planning unit 28 can optimize the operation by minimizing this deviation as much as possible. 【0023】 The IoT function unit 29 plays a predetermined role as an IoT terminal assigned to the terminal device 20 in the IoT system 100 for realizing a predetermined purpose, and is responsible for transmitting arbitrary information collected by the terminal device 20 according to the predetermined purpose (for example, in the case of agricultural IoT, environmental information such as weather information that can be obtained by the environmental information acquisition unit 24) to another terminal 40 in the IoT network NW. The IoT function unit 29 may also receive information transmitted from the other device 40. 【0024】 Figure 5 is a flowchart of the operation of the terminal device 20 according to one embodiment (mainly operations related to the control unit 27). When starting the flowchart, the system compares the illuminance, based on at least the illuminance information among the environmental information acquired from the planning unit 28, with a preset threshold to determine whether the illuminance in the environment where the solar cell equipment 10 is located is low or high. If it is determined to be low, flowchart F51 is executed; if it is determined to be high, flowchart F52 is executed. 【0025】 When flow F51 is started, in step S51 the planning unit 28 determines whether the current time corresponds to a data transmission trigger (transmission timing, for example, every 10 minutes) set in the IoT function unit 29 to another device 40. If it does, the unit proceeds to step S52; otherwise, it remains in step S51 and waits until the timing arrives. 【0026】 In step S52, the planning unit 28 determines whether the output voltage V(t) of the solar cell, monitored by the output voltage monitoring unit 52 up to the current time t, has risen to the maximum operating point voltage value Vmax and is above it at the current time t (i.e., V(t) > Vmax). If the determination is positive, the process proceeds to step S53; otherwise, it proceeds to step S55. In step S55, (unlike when proceeding to step S53,) data is not transmitted from the IoT function unit 29 to the other device 40 at the current time t, and the process returns to step S51. (Therefore, even if the transmission timing in step S51 is set to, for example, every 10 minutes, if the output voltage V(t) at the current time t is insufficient, the resulting data transmission may occur every 20 or 30 minutes.) 【0027】 In step S53, the planning unit 28 instructs the IoT function unit 29 to transmit data to another device 40. Following this instruction, data transmission is performed using the output voltage of the solar cell received by the receiving unit 21, after which the process proceeds to step S54. In step S54, the output voltage monitoring unit 22 confirms that the output voltage of the solar cell has decreased due to the use of power for the data transmission, and the process returns to step S51. (Note that step S54 is not a spontaneous processing step in the terminal device 20, but rather a confirmation that the output voltage decreases as a result of the processing in step S53.) 【0028】 On the other hand, when flow F52 starts in Figure 5, in step S61 the planning unit 28 is constantly monitoring the output voltage of the solar cell obtained from the output voltage monitoring unit 22, and then the process proceeds to step S62. 【0029】 In step S62, the planning unit 28 determines whether the output voltage V(t) of the solar cell, which is monitored by the output voltage monitoring unit 52 up to the current time t, has risen to a value Vmax+ΔV, which is the maximum operating point voltage value Vmax plus a predetermined value ΔV>0, and whether it is above this value at the current time t (i.e., V(t)>Vmax+ΔV). If the determination is positive, the unit proceeds to step S63; otherwise, the unit proceeds to step S65. In step S65, (unlike when proceeding to step S63,) the unit returns to step S61 without transmitting data from the IoT function unit 29 to the other device 40 at the current time t. 【0030】 In step S63, the planning unit 28 instructs the IoT function unit 29 to transmit data to another device 40. Following this instruction, data transmission is performed using the output voltage of the solar cell received by the receiving unit 21, after which the process proceeds to step S64. In step S64, the output voltage monitoring unit 22 confirms that the output voltage of the solar cell has decreased due to the use of power for the data transmission, and the process returns to step S61. (Note that step S64 is not a spontaneous processing step in the terminal device 20, but rather a confirmation that the output voltage decreases as a result of the processing in step S63.) 【0031】 Figure 6 is a schematic example of the behavior of the output voltage of the solar cell (the behavior obtained as a result of continuous monitoring by the output voltage monitoring unit 22) realized by the flow described in Figure 5. While flow F51 is continuously applied, the behavior is as shown in graph example EX61, and while flow F52 is continuously applied, the behavior is as shown in graph example EX62. 【0032】 In graph example EX61, the application of flow F51 allows the output voltage to not drop too low from the maximum operating point voltage, even when ambient light levels are relatively low. This enables the power generated from the solar cell to be utilized as efficiently as possible, while simultaneously allowing the terminal device 20 to intermittently perform its assigned role of data transmission as frequently as possible. 【0033】 In graph example EX62, the application of flow F52 allows for the most efficient use of power generated from solar cells when the ambient illuminance is relatively high, by preventing the output voltage from rising too high above the maximum operating point voltage. Furthermore, by utilizing the abundant power generated from solar cells available due to the relatively high illuminance, it becomes possible to intermittently perform the data transmission processing, which is the role assigned to the terminal device 20, at a high frequency. 【0034】 In the flow chart of Figure 5, the maximum operating point voltage Vmax can be obtained in the planning unit 28 by comparing the environmental information with predetermined map information representing the function, either as a function Vmax(L(t)) of the amount of sunlight L(t) at the current time t obtained from the environmental information acquisition unit 24, or as a function Vmax(L(t),T(t)) which also includes the temperature T(t) at the current time t, also obtained in the same manner. 【0035】 Figure 7 is a schematic example of the behavior of the output voltage of a solar cell (behavior obtained as a result of constant monitoring by the output voltage monitoring unit 22) realized by a modified version (referred to as the second embodiment) of the embodiment of Figure 5 (referred to as the first embodiment). Example EX71 in Figure 7 is the same as Example EX61 in Figure 6 and represents the behavior in the case of low illuminance. On the other hand, Examples EX72 and EX73 in Figure 7 correspond to the case of high illuminance in Example EX61 in Figure 6, but this is further divided into two stages, with the lower end of the high illuminance being referred to as medium illuminance, and the behavior of Example EX72 is realized as the same behavior as Example EX62 in Figure 5. On the other hand, as a new behavior in the second embodiment, the behavior on the higher end of the high illuminance is shown as Example EX73. 【0036】 In the first embodiment shown in Figures 5 and 6, it was assumed that the solar cell output power obtained by the receiving unit 21 was used entirely for the operation of the terminal device 20 (that the solar cell supplied all of the operating power for the terminal device 20) while the energy storage unit 23 was not charged at all times. On the other hand, in the second embodiment shown in Figure 7, the energy storage unit 23 is also charged when it is determined that the amount of sunlight is particularly high. Specifically, in example EX62 of Figure 6, data transmission is performed at a high frequency when the amount of sunlight is high, and the energy storage unit 23 is not charged. In example EX72 of Figure 7, the same as example EX62, whereas in example EX73, unlike example EX62, data transmission is performed at a high frequency and the energy storage unit 23 is also charged because the amount of sunlight is significantly high. 【0037】 The second embodiment of FIG. 7 can be realized as follows as a modification of the first embodiment by providing a first threshold value TH1 and a second threshold value TH2 (TH2 > TH1) for the amount of sunlight exposure. ● First case... When the amount of sunlight exposure < TH1, perform the control of Example EX71 (the same as Example EX61). ● Second case... When TH1 ≤ amount of sunlight exposure < TH2, perform the control of Example EX72 (the same as Example EX62). ● Third case... When the amount of sunlight exposure ≥ TH2, perform the control of Example EX73. 【0038】 The classification between the second case and the third case is performed as additional processing when the step S62 of the flow F52 in FIG. 5 is a positive determination. When it corresponds to the second case, only data transmission is performed in step S63, and the charging of the power storage unit 23 is not performed. When it corresponds to the third case, data transmission is performed in step S63, and the charging of the power storage unit 23 is also performed. 【0039】 As described above, according to each embodiment of the present invention, regarding the terminal device 20 in the IoT system 100 that operates receiving power supply from the solar cell, it is possible to achieve both ensuring the power generation efficiency of the solar cell and ensuring the operation efficiency of the terminal device 20. 【0040】 Figure 8 shows the effects of an embodiment of the present invention as schematic example EX91, compared to a proportional example EX92 in which the present invention is not applied. In proportional example EX92, because scheduling control as in the embodiment of the present invention is not performed, data is transmitted too frequently when the amount of sunlight is low, causing the output voltage of the solar cell to drop significantly below the maximum operating point voltage. This results in a waiting period for the voltage to recover to the maximum operating point voltage, leading to uneven data transmission intervals and inefficient use of the solar cell's power. In contrast, in schematic example EX91 of the embodiment of the present invention, for example, according to the first embodiment, data is transmitted as frequently as possible when the illuminance is low, without dropping too far below the maximum operating point, and when the illuminance is high, data is transmitted at a high frequency without exceeding the maximum operating point too much. This makes it possible to efficiently utilize the solar cell's power while efficiently fulfilling the role of the IoT system 100. 【0041】 The following sections will explain various supplementary examples, alternative examples, and additional examples. 【0042】 (1) According to embodiments of the present invention, the IoT system 100 can be efficiently operated using solar cells, which are a form of green energy, as a power source. This contributes to reducing the emission of carbon dioxide, which is a cause of global warming, and thus contributes to Goal 13 of the United Nations Sustainable Development Goals (SDGs), "Take urgent action to combat climate change and its impacts." 【0043】 (2) Figure 9 is a flowchart of the operation of the terminal device 20 according to the third embodiment (mainly the power control case distinction among the operations related to the control unit 27). The third embodiment, like the first and second embodiments, efficiently realizes the functions of the IoT system 100 using solar cells as much as possible, and the third embodiment takes into account the time of day and other factors for the power control case distinction. That is, power utilization can be optimized by rule-based case distinction as shown in Figure 9, using information on the maximum operating point corresponding to the illuminance (and temperature) of the environment in which the solar cells are placed, and information on the predetermined power consumption of the terminal device 20 in various states of the terminal device 20 (a state determined by distinguishing whether it is transmitting data or in standby mode without transmitting data, and whether it is charging the energy storage unit 23 in parallel with this data transmission / non-transmission). 【0044】 The flow in Figure 9 is executed during the daytime, not at night, when solar power is available. When the flow is started, step S81 determines whether it is unnecessary for the terminal device 20 to transmit data to another device 40 at set intervals in the predetermined role assigned to it in the IoT system 100. If the determination is negative, the process proceeds to step S86; if it is positive, the process proceeds to step S82. In step S86, the maximum operating voltage is not maintained, and data is transmitted periodically at the set intervals, and the storage unit 23 is also set to be charged. Step S86 is a case where the utilization of power from the solar cell is not necessarily optimized by prioritizing the pre-set scheduling (i.e., selectively disabling the efficiency improvements according to the present invention). 【0045】 If the process proceeds to step S82 or beyond, power efficiency is ensured, even if it means deviating somewhat from the pre-set schedule. In step S82, it is determined whether the current amount of sunlight is equal to or greater than the first threshold TH1. If the result is negative (sunlight amount is "low"), the process proceeds to step S83; if the result is positive (sunlight amount is "medium" or "high"), the process proceeds to step S87. 【0046】 In step S83, it is determined whether the current time is close to evening based on whether the current time falls within a predetermined time period set as evening. If the answer is yes (it is evening), the process proceeds to step S84, where the energy storage unit 23 is charged to maintain the maximum operating voltage, and data transmission processing is performed with a reduced data transmission interval. If the answer is no (it is daytime), the process proceeds to step S85, where data transmission is performed with a reduced data transmission interval to maintain the maximum operating voltage, and the energy storage unit 23 is not charged. 【0047】 The difference between steps S84 and S85 is whether or not the energy storage unit 23 is charged. In step S84, the energy storage unit 23 is charged in advance in the evening to prepare for nighttime when power from the solar cells is unavailable. As a result, the data transmission frequency is lower than in step S85. 【0048】 In step S87, it is determined whether the current amount of sunlight is equal to or greater than the second threshold TH2 (as mentioned above, TH2 > TH1). If the result is negative (sunlight amount is "medium"), the process proceeds to step S88; if the result is positive (sunlight amount is "high"), the process proceeds to step S90. In step S90, since there is abundant sunlight, the energy storage unit 23 is charged while maintaining the maximum operating voltage, and data is transmitted periodically (periodically without breaking the pre-set schedule). 【0049】 In step S88, it is determined whether the current time is close to evening based on whether the current time falls within a predetermined time period set as evening. If the answer is yes (it is evening), the process proceeds to step S89, where the energy storage unit 23 is charged to maintain the maximum operating voltage, and data transmission processing is performed at a reduced data transmission interval. If the answer is no (it is daytime), the process proceeds to step S91, where data is transmitted periodically (periodically without breaking a predetermined schedule) to maintain a voltage near the maximum operating voltage, and the energy storage unit 23 is not charged. 【0050】 The difference between steps S89 and S91 is whether or not the energy storage unit 23 is charged, and whether or not it follows a pre-set schedule. In step S89, the energy storage unit 23 is charged in advance in the evening to prepare for nighttime when solar power is unavailable. As a result, the data transmission frequency is lower than in step S91. 【0051】 (3) <Hardware Configuration> Figure 10 shows an example of a hardware configuration in a typical computer. The terminal device 20 can be realized as one or more computer devices 70 having such a configuration. When the terminal device 20 is realized with two or more computer devices 70, information necessary for processing may be sent and received via a network. The computer device 70 includes a CPU (Central Processing Unit) 71 that executes predetermined instructions, a GPU (Graphics Processing Unit) 72 as a dedicated processor that executes some or all of the execution instructions of the CPU 71 on behalf of or in cooperation with the CPU 71, RAM 73 as main memory that provides a work area to the CPU 71 (and GPU 72), ROM 74 as auxiliary memory, a communication interface 75, a display 76, an input interface 77 that accepts user input via a mouse, keyboard, touch panel, etc., sensors 81 that can constitute the sensors of the environmental information acquisition unit 24 and a bus BS for sending and receiving data between them, and power supply-related circuits 82 that can constitute a receiving unit 21, an output voltage monitoring unit 22, and a power storage unit 23. 【0052】 The control unit 27 of the terminal device 20 can be implemented by a CPU 71 and / or GPU 72 that read and execute predetermined programs corresponding to the functions of each part from ROM 74. Both the CPU 71 and GPU 72 are types of arithmetic units (processors). Furthermore, when display-related processing is performed, the display 76 may operate in conjunction, and when communication-related processing related to data transmission and reception is performed, the communication interface 75 may also operate in conjunction. [Explanation of Symbols] 【0053】 100…IoT system, 10…Solar cell equipment, 20…Terminal device, 40…Other device 11...Power generation unit, 12...Output unit, 21...Receiver unit, 22...Output voltage monitoring unit, 23...Energy storage unit, 24...Environmental information acquisition unit, 25...Sunshine information acquisition unit, 26...Temperature acquisition unit, 27...Control unit, 28...Planning unit, 29...IoT function unit

Claims

[Claim 1] A terminal device in a network, configured to operate using power obtained from a solar cell, The first process of transmitting data is performed after monitoring the output voltage obtained from the solar cell and adjusting the interval for transmitting data to the network so that the output voltage is maintained near the maximum operating voltage point of the solar cell. The terminal device is equipped with a rechargeable battery and is configured to be able to charge the rechargeable battery with power obtained from the solar cell. When the amount of sunlight on the solar cell is obtained and it is determined that the amount of sunlight is moderate, In the first process, the interval for data transmission is adjusted to such a frequency that the output voltage does not exceed the maximum operating voltage point of the solar cell by a predetermined amount, and then the data transmission is performed. The amount of sunlight on the solar cell is obtained, and if it is determined that the amount of sunlight is greater than the moderate level, The terminal device is characterized in that, in the first process, the interval for data transmission is adjusted to a frequency such that the output voltage does not exceed the maximum operating voltage point of the solar cell by a predetermined amount, and then data transmission is performed, and the rechargeable battery is charged with power obtained from the solar cell. [Claim 2] A program characterized by causing a computer to function as the terminal device described in claim 1.