Sensor, sensor control method, and sensor network system

Abstract

The system quickly notifies users of failures in the sensor network that communicates between sensors. [Solution] A sensor that constitutes a sensor network for communication between sensors detects a communication failure in the sensor network between the sensor and the nearest sensor among the multiple sensors that constitute the sensor network. When a communication failure in the sensor network with the nearest sensor is detected, the sensor increases the output of the radio waves emitted from the sensor to search for a sensor other than the nearest sensor among the multiple sensors that constitute the sensor network, and transmits information to be notified to the user terminal to the discovered other sensor.

Description

Technical Field

[0001] The present disclosure relates to a sensor, a method for controlling a sensor, and a sensor network system, and more particularly to a sensor that performs wireless communication between a plurality of sensors, a method for controlling a sensor, and a sensor network system.

Background Art

[0002] When a major disaster occurs, damage information is delivered to each user terminal via the communication networks of each mobile phone carrier (communication carrier). In addition, there is disaster prevention radio as a means of transmitting disaster information in the region.

[0003] When a disaster occurs, residents, supporters, or rescuers confirm the damage situation by phone, through the Internet, or visually.

[0004] In recent years, a communication technology called wireless sensor networks (WSN), or simply sensor networks, is known.

[0005] Patent Document 1 discloses an example of a disaster prevention sensor network system. In the disaster prevention sensor network system described in Patent Document 1, a sensor detects disaster prevention information such as falling rocks or rising water levels in rivers, and provides the detected disaster prevention information to a user terminal via a network.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Telephone and internet use depend on the functionality of communication networks, but during disasters, it is anticipated that communication carriers' networks may become unusable due to base station failures, etc. Therefore, there is a need to restore sensor networks as quickly as possible so that residents, aid workers, and rescuers can obtain information about the extent of damage in the affected areas and other information relevant to the disaster.

[0008] This disclosure has been made in view of the above-mentioned issues, and its purpose is to enable the sensor network, which communicates between sensors, to be quickly restored after a communication failure occurs, by promptly notifying users of failures in the sensor network that communicates between sensors. [Means for solving the problem]

[0009] A sensor according to one aspect of the present disclosure is a sensor that constitutes a sensor network for communication between sensors, and comprises: detection means for detecting a communication failure in the sensor network between the sensor and the nearest sensor among a plurality of sensors constituting the sensor network; search means for a sensor other than the nearest sensor among the plurality of sensors constituting the sensor network by increasing the output of radio waves output from the sensor when a communication failure in the sensor network between the sensor and the nearest sensor is detected; and transmission means for transmitting information to be notified to a user terminal to the discovered other sensor.

[0010] A sensor network system according to one aspect of the present disclosure comprises a plurality of sensors according to one aspect of the present disclosure, and causes the sensors to search for surrounding sensors using radio waves, and causes the sensors to construct a sensor network between the sensors and the surrounding sensors discovered by radio waves. [Effects of the Invention]

[0011] According to one aspect of this disclosure, a failure in a sensor network communicating between sensors can be quickly notified to the user. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an example of a sensor network system according to one embodiment. [Figure 2] This is a flowchart showing the flow of how multiple sensors build a sensor network in a sensor network system according to one embodiment. [Figure 3] This is a flowchart showing the flow of fault / environmental information transfer between sensors in a sensor network system according to one embodiment. [Figure 4] Block diagram showing an example of the sensor configuration according to one embodiment. [Figure 5] This flowchart shows an example of the operation of a sensor according to one embodiment. [Figure 6] This figure shows an example of the hardware configuration of a sensor according to one embodiment. [Modes for carrying out the invention]

[0013] (Regarding sensor networks) Sensor networks, also known as wireless sensor networks (WSNs), are wireless network technologies that enable multiple sensors to be scattered throughout a space and work together to collect data on the environment and physical conditions. They are one of the core technologies used in fields such as M2M (Machine to Machine) and IoT (Internet of Things).

[0014] [Embodiment 1]

[0015] (Sensor network system 1) Referring to Figure 1, the configuration of the sensor network system 1 according to this embodiment will be described.

[0016] As shown in FIG. 1, the sensor network system 1 includes a user terminal 100 and a plurality of sensors A, B, C, and D. In the sensor network system 1, sensor networks AB, AC, BC, and CD connecting between sensors A to D, and a terminal / sensor network connecting the user terminal 100 and sensor B are configured. Sensors A to D are arranged around environments where signs of disasters can be recorded, such as rivers, mountain slopes, tunnels, buildings, etc., or monitoring targets such as buildings that may collapse. Note that the sensor network system 1 may further include other sensors E, F, or other sensors not shown in the figure.

[0017] Note that in the following description, "sensors A to D" has the meaning of either "all of sensors A, B, C, and D" or "each of sensors A, B, C, and D" depending on the context. Also, "sensor networks AB to CD" has the meaning of either "all of sensor networks AB, AC, BC, and CD" or "each of sensor networks AB, AC, BC, and CD" depending on the context.

[0018] During non-disaster times, a plurality of sensors A to D are arranged in an area (such as a water source, mountainous area, etc.) where there is a monitoring target. The plurality of sensors A to D have completed the initial setting of the communication connection so that they can communicate wirelessly with each other.

[0019] Sensors A to D detect environmental information such as the water level of a river, the moisture content of soil on a slope, the presence or absence of cracks in a tunnel or building, and transmit the detected environmental information to the nearest sensor. Also, sensors A to D monitor the communication status of sensor networks AB to CD and determine whether communication is possible between sensors A to D and the nearest sensor. If communication is not possible between sensors A to D and the nearest sensor, the sensor networks AB to CD are reconstructed between sensors that can communicate, and fault information regarding the faults of sensor networks AB to CD and environmental information detected by sensors A to D (hereinafter referred to as fault / environmental information) are transmitted and received.

[0020] The user terminal 100 is a general-purpose wireless communication terminal such as a mobile phone, smartphone, PC (Personal Computer), etc. The user terminal 100 receives failure / environment information from sensor A.

[0021] The sensor network AB~CD is used to transmit and receive failure / environment information between sensors A~D without relying on an existing general-purpose communication network. When communication with the nearest sensor becomes impossible for sensors A~D, they detect a communication failure in the sensor network AB~CD.

[0022] The terminal / sensor network is used for the user terminal 100 to receive failure / environment information from sensor A. The terminal / sensor network is a wireless communication network such as Wi-Fi (registered trademark), the wireless communication network of a communication carrier, Bluetooth (registered trademark) communication, or a wireless communication network similar to the sensor network AB~CD.

[0023] In a mesh communication network or an ad hoc communication network, even if the connection between adjacent nodes is broken, as long as there is a communication path through which connection can be made by detour, the connection between nodes can be ensured. However, if there is no communication path through which connection can be made by detour, communication between adjacent nodes becomes impossible.

[0024] Sensors A~D detect the communication status of the sensor network AB~CD in real time. When a disaster occurs and a sensor network AB~CD with communication failure is found due to a failure of the communication function of a sensor, etc., sensors A~D notify the user terminal 100 to that effect. As a result, the user can grasp the sensor network AB~CD with communication failure, and thus can identify the area where damage has occurred.

[0025] Furthermore, if a failure occurs in the sensor network AB-CD, making communication with the nearest sensor impossible, sensors A-D will search for another available sensor by transmitting radio waves. If no other available sensor is found, sensors A-D will increase the output of the radio waves they transmit to extend the search range and continue searching for another available sensor.

[0026] This makes it possible to restore the sensor network AB-CD among the communicable sensors A-D, as long as sensors A-D themselves are operational.

[0027] A mesh communication network, independent of carrier communication networks, is established between sensors A to D to transmit and receive the aforementioned fault / environmental information. Each of sensors A to D distributes fault / environmental information to the user terminal 100 in real time, either through this mesh communication network or using general-purpose communication such as Wi-Fi (registered trademark).

[0028] This allows users to obtain information about disasters. Furthermore, users can predict which areas have suffered what kind of damage, without having to go to the site, based on the failure status of sensor networks A through C.

[0029] If communication (M2M) is possible between sensors A to D via the sensor network AB to CD, sensors A to D will exchange fault / environmental information generated by each sensor. If sensors A to D can find fewer than a predetermined number of other sensors with which they can communicate, sensors A to D will issue a notification indicating that the sensor network AB to CD is vulnerable.

[0030] Next, we will explain an example of the detailed configuration of sensors A through D.

[0031] Sensors A through D have a sensing function to detect environmental information around their placement locations, a network fault detection function to detect faults in the sensor network AB through CD, and a timestamp function to add time information to the detected fault / environmental information. Furthermore, sensors A through D have a control function to control the output of radio waves.

[0032] The sensing function periodically detects environmental information around sensors A to D. The timestamp function adds information indicating the detection time to the fault / environmental information detected by sensors A to D. The timestamp function is used to determine duplication of fault / environmental information when sensors A to D receive fault / environmental information from the nearest sensor. The network fault detection function determines a fault in the sensor network if the sensor network AB to CD, to which sensors A to D are connected, becomes unable to communicate.

[0033] Furthermore, sensors A through D have internal storage. This internal storage stores fault / environmental information detected by sensors A through D, as well as fault / environmental information received by sensors A through D from other sensors.

[0034] Sensors A through D transmit fault / environmental information they generate to the nearest sensor via the sensor network. Sensors A through D also receive fault / environmental information transmitted from other sensors. The sensor network AB through CD, implemented using a communication method different from the carrier's wireless communication network (e.g., local 5G), is used for transmitting and receiving fault / environmental information.

[0035] Furthermore, the internal storage stores logs containing fault / environmental information detected by sensors A through D, with timestamps added. Sensors A through D update the logs in the internal storage based on fault / environmental information received from other sensors A through D.

[0036] Specifically, if the timestamp of a newly added log is newer than the timestamp of a log already stored in the internal storage of sensors A to D, sensors A to D will overwrite the old log with the new one. On the other hand, if the timestamp of a newly added log is older than the timestamp of a log already stored, sensors A to D will discard the log that was attempted to be added.

[0037] For example, if the fault / environmental information received by sensors A-D is newer than the fault / environmental information stored in the internal storage, sensors A-D will update the fault / environmental information stored in the internal storage with the fault / environmental information received by sensors A-D. On the other hand, if the fault / environmental information stored in the internal storage is newer than the fault / environmental information received by sensors A-D, sensors A-D will discard the received fault / environmental information.

[0038] Next, we will explain the operation of automatically establishing a sensor network AB-CD between sensors A-D when sensors A-D are activated, and the operation of sharing (sending and receiving) fault / environmental information detected by sensors A-D with other sensors.

[0039] In one example, fault / environmental information is transmitted from sensor C, received by sensor A via sensor B, and then transmitted to sensor A. In this case, the fault / environmental information log from sensor C is stored in the internal storage of sensors A and B.

[0040] The operation of sensors A to D when sensor networks AB to CD are constructed will be explained in "Flow of Sensors A to D Automatically Constructing the Sensor Network". Next, the operation of passing fault / environmental information between sensors A to D will be explained in "Flow of Fault / Environmental Information Transfer". At the same time, the operation in the event of a fault in sensor network BC will also be explained.

[0041] (A flow in which sensors A to D automatically build a sensor network AB to CD) Referring to Figure 2, the operational flow for constructing the sensor network AB-CD will be explained.

[0042] As shown in Figure 2, initially, the power to sensors A through D is turned on (S101).

[0043] Next, sensors A to D transmit radio waves to search for surrounding sensors (S102).

[0044] Sensors A to D receive responses from surrounding sensors that have received the radio waves (S103).

[0045] Sensors A through D wait for a certain period of time to check for responses from other sensors. If a predetermined number of sensors are not found after waiting for a certain period of time (No in S104), proceed to step S107.

[0046] When sensors A to D receive responses from a predetermined number of sensors (Yes in S104), they complete the construction of the sensor network AB to CD (S105) and stop searching for surrounding sensors (S106).

[0047] If a predetermined number of sensors are not found after waiting for a certain period of time (No in S104), it is determined whether the output of the radio waves transmitted by sensors A to D has reached a predetermined upper limit (S107). If the output of the radio waves transmitted by sensors A to D is less than the predetermined upper limit (No in S107), the output of the radio waves is increased, and the system returns to step S102 to resume searching for surrounding sensors. At this time, the user can arbitrarily decide how much to increase the output transmitted by sensors A to D.

[0048] On the other hand, if the output of the radio waves transmitted by sensors A to D exceeds a predetermined upper limit (Yes in S107), sensors A to D stop searching (S108) and issue a notification that there is a vulnerability in the sensor network AB to CD (S109).

[0049] This completes the operational flow for constructing the sensor network AB-CD.

[0050] In existing Wi-Fi and Bluetooth mesh communication networks, radio waves are continuously transmitted at a constant output. On the other hand, sensors A to D in this embodiment 1 gradually increase the output of the radio waves they transmit, as long as the output of the radio waves transmitted by sensors A to D does not fall below a predetermined upper limit, and continue searching for other sensors in the surrounding area until a predetermined number of other sensors capable of communication are found. This makes it possible to construct a redundant sensor network while minimizing power consumption.

[0051] (Flowchart for transferring fault / environmental information) Referring to Figure 3, the operation flow for the transfer of fault / environmental information between sensors A to D will be explained. Here, an example of sending and receiving fault / environmental information between sensor C and sensors A and B will be explained.

[0052] Sensor C acquires or generates fault / environmental information (S201).

[0053] Sensor C adds a timestamp to the acquired or generated fault / environmental information (S202).

[0054] Next, sensor C detects the nearest sensor B using radio waves (S203). Sensor C transmits fault / environmental information to the detected sensor B. In this example, the fault / environmental information held by sensor C is transmitted from sensor C to sensor B via the sensor network BC.

[0055] If a failure occurs in the sensor network BC due to a malfunction in the communication function of sensor B, and sensor C is unable to communicate with sensor B, sensor C will gradually increase its radio wave output while attempting to find another sensor. However, if sensor C cannot find another sensor even when its radio wave output reaches the predetermined upper limit (No in S203), sensor C will stop transmitting fault / environmental information (S204A).

[0056] On the other hand, if sensor A, which is different from sensor B, is detected before the radio wave output of sensor C reaches its upper limit (Yes in S203), sensor C transmits fault / environmental information to sensor A (S204B).

[0057] Sensor A receives fault / environmental information transmitted from Sensor C (S205).

[0058] After step S205, sensor A or sensor B (hereinafter referred to as "sensor A or B") checks the timestamp attached to the fault / environment information received from sensor C. If the timestamp of the received fault / environment information is older than the timestamp stored in sensor A or B's internal storage (Yes in S206), sensor A or B discards the received fault / environment information (S207A).

[0059] On the other hand, if the timestamp of the fault / environment information received by sensor A or B is newer than the timestamp stored in sensor A or B's internal storage (No in S206), sensor A or B overwrites the fault / environment information stored in sensor A or B's internal storage with the fault / environment information received from sensor C (S207B).

[0060] This concludes the flow for transferring fault / environmental information between sensors.

[0061] In this way, even if there is a failure in the sensor network BC, the failure / environmental information acquired or generated by sensor C can be shared with sensor A, which can communicate with sensor C, and the user can learn from sensor A via the terminal / sensor network that a failure has occurred in the sensor network BC.

[0062] (Effects of this embodiment) According to the configuration of this embodiment, the sensor network system 1 causes sensors A to D to search for surrounding sensors using radio waves, and establishes sensor networks AB to CD between sensors A to D and the surrounding sensors discovered by radio waves. Sensors A to D detect a communication failure in the sensor network between sensors A to D and the sensor closest to them among the multiple sensors that make up sensor networks AB to CD. When sensors A to D detect a communication failure in the sensor network with the nearest sensor, they increase the output of the radio waves emitted from sensors A to D to search for a sensor other than the nearest sensor among the multiple sensors that make up sensor networks AB to CD. Then, sensors A to D transmit fault / environmental information to the other sensor that is discovered, which is then notified to the user terminal 100.

[0063] If there is no communication failure in the sensor network between sensors A-D and the nearest sensor from sensors A-D, sensors A-D transmit fault / environmental information to the nearest sensor. On the other hand, if there is a communication failure in the sensor network between sensors A-D and the nearest sensor from sensors A-D, sensors A-D transmit fault / environmental information to a sensor other than the nearest sensor. The nearest sensor or the other sensor notifies the user terminal 100 of the fault / environmental information. This allows the user to know the extent of damage at the location where sensors A-D are placed and the communication failure in the sensor network AB-CD.

[0064] Therefore, users will be able to quickly recover from communication failures in the sensor network AB to CD.

[0065] [Embodiment 2] In this second embodiment, we will describe an example of the functions of sensors A to D described in the first embodiment.

[0066] (Configuration of sensor 20) Figure 4 is a block diagram showing the configuration of the sensor 20 according to this second embodiment. As shown in Figure 4, the sensor 20 includes a detection unit 21, a search unit 22, and a transmission unit 23.

[0067] Sensor 20 is one of the sensors that make up a sensor network that communicates with other sensors.

[0068] The detection unit 21 detects a communication failure in the sensor network between sensor 20 and the sensor closest to sensor 20, among the multiple sensors that make up the sensor network. The detection unit 21 is an example of a detection means.

[0069] For example, the detection unit 21 detects that communication between sensor 20 and the nearest sensor is impossible. In such a case, the detection unit 21 notifies the search unit 22 that it has detected a communication failure in the sensor network.

[0070] When the search unit 22 detects a communication failure in the sensor network between sensor 20 and the nearest sensor, it increases the output of the radio waves emitted from sensor 20 to search for a sensor other than the nearest sensor among the multiple sensors that make up the sensor network. The search unit 22 is an example of a search means.

[0071] For example, the search unit 22 is notified by the detection unit 21 that a communication failure in the sensor network has been detected. At this time, the search unit 22 increases the output of the radio waves emitted from sensor 20 to a predetermined upper limit until a sensor other than the closest sensor to sensor 20 is found. If, even after increasing the output of the radio waves emitted from sensor 20 to a predetermined upper limit, another sensor cannot be found, the search unit 22 has the transmission unit 23 notify the user terminal 100 (Figure 1) that there is a vulnerability in the sensor network.

[0072] The transmitting unit 23 transmits information to the user terminal 100 to another sensor that has been detected. The transmitting unit 23 is an example of a transmission means.

[0073] For example, the transmitting unit 23 transmits fault / environmental information to another sensor indicating that a communication failure has occurred in the sensor network between sensor 20 and the nearest sensor from sensor 20. The transmitting unit 23 also adds a timestamp to the fault / environmental information transmitted to the other sensor. However, if the search unit 22 cannot find another sensor even when the output of the radio waves emitted from sensor 20 is increased to the upper limit, the transmitting unit 23 stops or cancels transmitting the fault / environmental information.

[0074] (Operation of sensor 20) Figure 5 is a flowchart showing the operation of the sensor 20 according to this second embodiment.

[0075] As shown in Figure 5, first, the detection unit 21 detects a communication failure in the sensor network between sensor 20 and the sensor closest to sensor 20, among the multiple sensors that make up the sensor network (S201).

[0076] Next, if the search unit 22 detects a communication failure in the sensor network between sensor 20 and the nearest sensor, it increases the output of the radio waves emitted from sensor 20 to search for a sensor other than the nearest sensor among the multiple sensors that make up the sensor network (S202).

[0077] Finally, the transmission unit 23 transmits fault / environmental information to another detected sensor, which will then be notified to the user terminal 100 (Figure 1) (S203).

[0078] This concludes the operation of the sensor 20 according to this second embodiment.

[0079] (Effects of this embodiment) According to the configuration of this embodiment, the detection unit 21 detects a communication failure in the sensor network between sensor 20 and the sensor closest to sensor 20, among the multiple sensors that constitute the sensor network. When a communication failure in the sensor network between sensor 20 and the closest sensor is detected, the search unit 22 increases the output of the radio waves emitted from sensor 20 to search for a sensor other than the closest one among the multiple sensors that constitute the sensor network. The transmission unit 23 transmits fault / environmental information to the discovered sensor, which is then notified to the user terminal 100.

[0080] If there is no communication failure in the sensor network between sensor 20 and the nearest sensor, the transmission unit 23 transmits fault / environmental information from sensor 20 to the nearest sensor. On the other hand, if there is a communication failure in the sensor network with the nearest sensor, the transmission unit 23 transmits fault / environmental information from sensor 20 to a sensor other than the nearest sensor. The nearest sensor or the other sensor then notifies the user terminal 100 of the fault / environmental information.

[0081] This allows users to know the extent of damage at the location where the sensors 20 are placed and whether there is a communication failure in the sensor network. As a result, users can quickly restore the sensor network after a communication failure.

[0082] [Other Embodiments] In the above embodiment 1, sensors A to D are used to construct a sensor network AB to CD. However, instead of sensors A to D, a low-power wireless device having equivalent functionality to sensors A to D may be used to construct the communication network.

[0083] Furthermore, by combining the information generated by sensors A through D, it may be possible to predict the scale of a disaster or detect signs of a disaster.

[0084] (Example of the hardware configuration of sensor 20) Each component of the sensor 20 described in Embodiment 2 above represents a functional unit block. Some or all of these components are realized by an information processing device as shown in Figure 6. Figure 6 is a block diagram showing an example of the hardware configuration of the information processing device.

[0085] As shown in Figure 6, the computer 110 comprises a CPU (Central Processing Unit) 111, main memory 112, storage device 113, input interface 114, display controller 115, data reader / writer 116, and communication interface 117. Each of these components is connected to each other via a bus 121 to enable data communication. In addition to the CPU 111, or in place of the CPU 111, the computer 110 may also include a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array).

[0086] The CPU 111 loads the program (code) in this embodiment, stored in the storage device 113, into the main memory 112 and performs various calculations by executing them in a predetermined order. The main memory 112 is typically a volatile storage device such as DRAM (Dynamic Random Access Memory). The program in this embodiment is provided stored on a computer-readable recording medium 120. The program in this embodiment may also be distributed over the internet connected via the communication interface 117.

[0087] Specific examples of the storage device 113 include hard disk drives and semiconductor storage devices such as flash memory. The input interface 114 mediates data transmission between the CPU 111 and input devices 118 such as a keyboard and mouse. The display controller 115 is connected to the display device 119 and controls the display on the display device 119.

[0088] The data reader / writer 116 mediates data transmission between the CPU 111 and the recording medium 120, reads programs from the recording medium 120, and writes processing results from the computer 110 to the recording medium 120. The communication interface 117 mediates data transmission between the CPU 111 and other computers.

[0089] Specific examples of the recording medium 120 include general-purpose semiconductor memory devices such as CF (Compact Flash®) and SD (Secure Digital), magnetic recording media such as Flexible Disks, and optical recording media such as CD-ROMs (Compact Disk Read Only Memory).

[0090] (Note) Some or all of the above embodiments may also be described as follows, but are not limited to the following:

[0091] (Note 1) A sensor that constitutes a sensor network that communicates with other sensors, A detection means for detecting a communication failure in the sensor network between one of the multiple sensors constituting the sensor network and the sensor closest to it, When a communication failure in the sensor network between the sensor and the nearest sensor is detected, the search means increases the output of the radio waves emitted from the sensor to search for a sensor other than the nearest sensor among the plurality of sensors constituting the sensor network. A transmission means for transmitting information to be notified to the user terminal to the other sensor that was discovered, A sensor equipped with this feature.

[0092] (Note 2) If a communication failure is detected in the sensor network between the aforementioned sensor and the nearest sensor, the transmitting means transmits information indicating that a communication failure has occurred in the sensor network to the other sensor. The sensor described in Appendix 1, characterized by the features described herein.

[0093] (Note 3) The search means increases the output of the radio waves emitted from the sensor to a predetermined upper limit until the other sensor is found. The sensor described in Appendix 1, characterized by the features described herein.

[0094] (Note 4) If the search means cannot find the other sensor even when the output of the radio waves emitted from the sensor is increased to the upper limit, the transmitting means stops transmitting the information. The sensor described in Appendix 3, characterized by the features described herein.

[0095] (Note 5) The transmitting means adds a timestamp to the information to be transmitted to the other sensor. The sensor described in Appendix 1, characterized by the features described herein.

[0096] (Note 6) If the timestamp of the information received from the sensor is older than the information stored in the nearest sensor or the other sensor, the nearest sensor or the other sensor discards the received information. The sensor described in Appendix 5, characterized by the features described herein.

[0097] (Note 7) A method for controlling sensors that constitute a sensor network for communication between sensors, Among the multiple sensors constituting the sensor network, a communication failure in the sensor network between the sensor and the sensor closest to it is detected. If a communication failure is detected in the sensor network between the aforementioned sensor and the nearest sensor, the output of the radio waves emitted from the aforementioned sensor is increased to search for a sensor other than the nearest sensor among the multiple sensors that constitute the sensor network. The information to be notified to the user terminal is transmitted to the other sensor that was discovered. Sensor control method.

[0098] (Note 8) The system includes multiple sensors as described in any one of the items 1 to 6 of the appendix, The aforementioned sensor is instructed to search for surrounding sensors using radio waves. A sensor network is constructed between the aforementioned sensor and the surrounding sensors detected by radio waves. Sensor network system.

[0099] (Note 9) Until a predetermined number or more of the aforementioned surrounding sensors are detected, the sensors increase the output of their radio waves up to a predetermined upper limit. The sensor network system described in Appendix 8, characterized by the features described herein.

[0100] (Note 10) If the radio wave output is increased to the upper limit, but it is not possible to detect a predetermined number or more of the surrounding sensors, the sensor will notify that there is a vulnerability in the sensor network. The sensor network system described in Appendix 9, characterized by the features described herein.

[0101] Furthermore, some or all of the configurations described in Appendices 2 to 6, which are dependent on Appendice 1 above, may also be dependent on Appendice 8 in the same manner as in Appendices 2 to 6. Moreover, within the scope that does not deviate from each of the embodiments described above, some or all of the configurations described as appendices may also be dependent on various hardware, software, various recording means for recording software, or systems.

[0102] The present disclosure has been described above with reference to several embodiments. However, the present disclosure is not limited to the embodiments described above. Each embodiment can be combined with other embodiments as appropriate. Furthermore, various modifications to the configuration and details of the above embodiments can be made that will be understood by those skilled in the art within the scope of the present disclosure. [Industrial applicability]

[0103] This disclosure can be used, for example, in a sensor network system constructed by multiple sensors and a sensor network between those sensors. [Explanation of Symbols]

[0104] 1. Sensor Network System A-D Sensors 20 sensors 21 Detection unit 22 Search Department 23 Transmitter 100 user terminals

Claims

1. A sensor that constitutes a sensor network that communicates with other sensors, A detection means for detecting a communication failure in the sensor network between a sensor and the sensor closest to it, among the multiple sensors constituting the sensor network. When a communication failure in the sensor network between the sensor and the nearest sensor is detected, the search means increases the output of the radio waves emitted from the sensor to search for a sensor other than the nearest sensor among the plurality of sensors constituting the sensor network. A transmission means for transmitting information to be notified to the user terminal to the other sensor that was discovered, A sensor equipped with this feature.

2. If a communication failure is detected in the sensor network between the aforementioned sensor and the nearest sensor, the transmitting means transmits information indicating that a communication failure has occurred in the sensor network to the other sensor. The sensor according to feature 1.

3. The search means increases the output of the radio waves emitted from the sensor to a predetermined upper limit until the other sensor is found. The sensor according to feature 1.

4. If the search means cannot find the other sensor even when the output of the radio waves emitted from the sensor is increased to the upper limit, the transmitting means stops transmitting the information. The sensor according to feature 3.

5. The transmitting means adds a timestamp to the information to be transmitted to the other sensor. The sensor according to feature 1.

6. If the timestamp of the information received from the sensor is older than the information stored in the nearest sensor or the other sensor, the nearest sensor or the other sensor discards the received information. The sensor according to feature 5.

7. A method for controlling sensors that constitute a sensor network for communication between sensors, Among the multiple sensors constituting the sensor network, a communication failure in the sensor network between the sensor and the sensor closest to it is detected. If a communication failure is detected in the sensor network between the aforementioned sensor and the nearest sensor, the output of the radio waves emitted from the aforementioned sensor is increased to search for a sensor other than the nearest sensor among the multiple sensors that constitute the sensor network. The information to be notified to the user terminal is transmitted to the other sensor that was discovered. Sensor control method.

8. User terminal and A plurality of sensors according to any one of claims 1 to 6, The aforementioned sensor is instructed to search for surrounding sensors using radio waves. A sensor network is constructed between the aforementioned sensor and the surrounding sensors detected by radio waves. Sensor network system.

9. Until a predetermined number or more of the aforementioned surrounding sensors are detected, the sensors increase the output of their radio waves up to a predetermined upper limit. The sensor network system according to claim 8, characterized in that it is as described above.

10. If the radio wave output is increased to the upper limit, but it is not possible to detect a predetermined number or more of the surrounding sensors, the sensor will notify that there is a vulnerability in the sensor network. The sensor network system according to feature 9.

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