JP4849549B2 - Wireless sensor system, living body health management system - Google Patents

Description

  The present invention relates to a wireless sensor system and a living body health management system.

In recent years, with the evolution of wireless communication technology and transmission / reception devices, various systems using wireless have been used.
Using such a system, it is also possible to observe or monitor the ecology of various animals. As conventional methods for investigating the ecology of animals, there are known attempts to detect the estrus from the location of migratory birds using a GPS terminal and the walking frequency of cattle.

  Recently, interest in “food safety” has been rapidly increasing due to the occurrence of BSE in Japan and the avian influenza epidemic. For the health management of animals used for food, an offline biopsy method has been mainly developed. However, these methods cannot perform inspection quickly, are expensive, and cannot be widely used in general. Therefore, studies are underway to determine whether such animal health management can be performed by attaching a sensor to an animal and collecting information from the sensor wirelessly.

In a system in which such animal health management is performed using radio, as one of the problems, there is a need to secure the power supply of the sensor in a state where it is attached to the measurement target. Moreover, the measured value in the sensor is analog data, and it is necessary to convert it into digital data in order to transmit it wirelessly. Power is also consumed by the A / D converter for this purpose.
In such a wireless sensor, various ideas have been made so far to reduce power consumption and extend the period in which the sensor can be used as much as possible. (For example, refer to Patent Document 1).

JP 2006-98398 A

  However, in applications where the sensor is attached to a living body such as an animal, it is difficult to supply power from the outside or charge the battery, and the entire sensor including the power supply is reduced in size and weight Therefore, a large battery or the like cannot be provided. Therefore, it is necessary to further reduce power consumption in such applications.

  In the conventional wireless sensor technology, an ad hoc method is employed in which direct communication is performed between child devices without using a parent device. However, in ad hoc communication, since individual terminals communicate asynchronously, communication is not established unless each terminal is always in a receiving state, and it is difficult to suppress power consumption.

In general, the temperature data detected by the sensor is transmitted intermittently at regular intervals, but in order to improve the response to changes, it is necessary to perform measurement at finer time intervals and transmit the measurement data. As a result, power consumption must be increased. In addition, when temperature is detected and transmitted intermittently, the detected measurement data is transmitted regardless of whether there is a change in state, so it can be said that unnecessary data transmission is performed, and there is room for reducing power consumption. is there.
The present invention has been made based on such a technical problem, and an object thereof is to provide a wireless sensor system and the like that can save power.

The wireless sensor system of the present invention, which has been made to solve the above-described problems, measures a physical quantity, receives a plurality of sensors that wirelessly transmit a telegram including the measured measurement data, and receives a telegram from the sensor. A wireless sensor system including a controller that transmits a radio wave for supplying power to the sensor to a radio wave generation source and stops a radio wave transmitted from the radio wave generation source to a plurality of sensors. By doing so, a command for the sensor is included in the radio wave.
In this way, by sending a command to cause the sensor to perform a predetermined operation to the radio wave transmitted to supply power to the sensor, on the sensor side, according to the timing, length, etc., when the radio wave is stopped, The sensor side can recognize the received command. Here, on the sensor side, a configuration for receiving radio waves for power supply and a configuration for transmitting a telegram including measurement data may be provided. In other words, the command from the controller can be received with a configuration such as an antenna for receiving radio waves for power supply, so standby power is not required to receive the command, and power consumption can be suppressed. .

In the controller, any command may be included in the radio wave for supplying power.
For example, when sending a message to a controller with a plurality of sensors in a time zone assigned to each sensor in advance, the time zone assigned to send a message in each of the plurality of sensors. The command can be used to correct the time. In this way, if time correction is performed based on a command in each of a plurality of sensors, when a message is transmitted to the controller in a time zone that is individually allocated to each sensor in advance, it is from other sensors. It is possible to prevent the transmission of the message and the timing from interfering with each other.
By sending a message from the sensor to the controller in the time zone assigned to each sensor in advance, there is no need to request a message from the controller to the sensor. Standby power for receiving the power is also unnecessary.
Further, even when the controller side requests the sensor to transmit a message, the command for that purpose may be included in the radio wave for supplying power to the sensor.

  In addition, in the controller, the message transmitted from each of the plurality of sensors is verified, and when there is an error in the verified message, a command for requesting retransmission of the message to the sensor that transmitted the message is sent Can also be included in the radio waves.

Such a wireless sensor system may be used for any application, but is suitable for use in a system for managing the health of a living body such as an animal.
The present inventors attach a sensor for measuring physical quantities such as acceleration, inclination, temperature, blood flow, blood pressure, and pulse to a living body to be managed in order to manage the health of the living body, and the measurement transmitted from the sensor A technology has been developed to determine the health state of a living body by determining the behavioral state of the living body based on the data of the results.
In such a technique, a physical sensor, a communication device, and the like can be contained in an ultra-small chip by the MEMS technique. By attaching such a chip to a large number of management organisms, collecting data sequentially, and analyzing the data using a computer, it is possible to manage a large number of management organisms at once.
When the wireless sensor system of the present invention is applied to such a system, the configuration is as follows.
That is, a system for managing the health of a living body, a plurality of sensors that are respectively attached to a plurality of living bodies that perform management, measure a predetermined physical quantity, and wirelessly transmit a telegram including the measured measurement data; An abnormality occurs in the health status of the living body based on a controller that receives a message from the sensor, a radio wave source that transmits a radio wave for supplying power to the sensor, and measurement data included in the message received by the controller. And a controller that determines whether or not the radio wave is transmitted from the radio wave generation source to the plurality of sensors, so that the command for the sensor is included in the radio wave. It is a configuration.

Here, the sensor to be used may have any configuration, but in order to reduce power consumption by suppressing the amount of measurement data and the frequency of data transmission, for example, an acceleration sensor or a temperature sensor having the following configuration is preferable. .
As an acceleration sensor, a deformable member that deforms according to acceleration, a piezoelectric material portion that is formed on the surface of the deformable member and generates an electric charge according to the deformation of the deformable member, and an electric charge generated at the piezoelectric material portion And a signal processing circuit that generates a signal when the obtained voltage is applied and the applied voltage exceeds a predetermined set voltage. A plurality of piezoelectric material portions are electrically connected in series to each other. Further, a plurality of signal processing circuits are provided, and are connected to at least two different piezoelectric material portions among the plurality of piezoelectric material portions connected in series. In each of the plurality of signal processing circuits, a voltage generated according to the number of piezoelectric material portions connected in series with the reference potential is applied from the piezoelectric material portion to which the signal processing circuit is connected. It has become so. Here, as the piezoelectric material portion, there may be a piezoelectric thin film, a piezoelectric thick film, and a piezoelectric material bulk bonded.
In such an acceleration sensor, when an acceleration is applied, the deformable member is deformed, and accordingly, the piezoelectric material portion generates a charge corresponding to the amount of deformation. Since a plurality of the piezoelectric material portions are electrically connected in series, the arrangement (order) from the ground side depends on the number of piezoelectric material portions connected in series with the reference potential. The generated voltage is different for each piezoelectric material part. When the voltage applied from the piezoelectric material portion to the signal processing circuit exceeds the set voltage, the signal processing circuit emits a signal. By recognizing the signal processing circuit that has emitted this signal, the degree of the applied acceleration is obtained. be able to. That is, the acceleration can be measured digitally based on signals emitted from a plurality of signal processing circuits.
In such an acceleration sensor, signals from a plurality of signal processing circuits can be output via an electrical connection, output via wireless communication, or stored in a memory circuit or the like. Etc. are possible.

  As a temperature sensor, the present inventors have focused on a temperature switch using a bimetal structure. The temperature switch using the bimetal structure has zero power consumption and the output is also an ON / OFF electrical switch, so it can be read directly as a digital signal. Can be minimal. However, since the bimetal temperature switch is a switch that operates at a specific temperature, it cannot be used for detecting a continuous temperature change within a wide temperature range.

Therefore, a bimetallic cantilever formed by laminating two types of materials having different linear expansion coefficients, an electric contact member facing the tip of the cantilever with a gap, and a voltage for applying a voltage to the cantilever or the electric contact member A plurality of sets of application circuits and detection circuits for detecting voltage fluctuations when the cantilever deformed in response to a temperature change comes into contact with or away from the electrical contact member, the length of the plurality of cantilevers or the tip of the cantilever It is preferable to use a temperature sensor characterized in that the gap between the portion and the electric contact member is formed to be different from each other.
In this way, when the length of the multiple cantilevers or the gap between the tip of the cantilever and the electrical contact member is made different between the multiple sets, when the bimetallic cantilever is deformed according to the temperature change The timing at which the tip of the cantilever and the electrical contact member come into contact with each other is different. The longer the cantilever is, the smaller the gap between the tip of the cantilever and the electrical contact member is, the smaller the temperature change is. In this way, when a temperature change corresponding to a temperature pitch determined according to a difference in cantilever length or a gap between the tip of the cantilever and the electrical contact member occurs between the groups, a plurality of groups The contact state between the cantilever and the electrical contact member changes, and the detection circuit can detect the contact (or separation) by voltage fluctuation. Thereby, temperature detection in a wide temperature range can be performed digitally by using a plurality of cantilevers.
Therefore, such a temperature sensor may further include a measurement control circuit that digitally measures the temperature based on signals emitted from a plurality of detection circuits.

By the way, it is preferable that the cantilever is formed of a conductive material at least on the side facing the electric contact member.
When the layer facing the electrical contact member of the cantilever is formed of a non-conductive material, the surface of the cantilever facing the electrical contact member is made of a conductive material and the cantilever is deformed in response to temperature deformation. It is preferable to provide a conducting member such as a wiring conducting to the electrical contact member.

  Further, the voltage application unit can be a capacitor fed from a power source. In such a configuration, it is not necessary to constantly apply a voltage, and the capacitor is discharged when the cantilever comes into contact with the electrical contact member, whereby the voltage change can be detected by the detection circuit. Then, when the capacitor is discharged, the power supply control circuit may perform power supply from the power source to the capacitor.

According to the present invention, a command is sent to a sensor using radio waves for supplying electric power, the time of each sensor is corrected to synchronize the timing at which data is transmitted from each sensor, or data transmission from each sensor is performed. A request for data retransmission was made when there was an error. As a result, the data from each sensor can be transmitted smoothly and reliably, and it is not necessary to spend standby power to receive these commands on each sensor side, thereby reducing power consumption.
In such a living body health management system, it is possible to extend the life of the sensor by suppressing power consumption. At this time, although there is no intention to limit the type of living body to be managed, it is particularly suitable for the purpose of performing health management especially on animals and the like whose behavior is difficult to control.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a diagram conceptually illustrating a bird flu monitoring system (biological health management system) 100 according to the present invention.
As shown in FIG. 1, one or more avian influenza monitoring systems 100 are installed to cover a sensor 120 attached to a bird (living body) managed in the management area 110 and the management area 110. A relay station (radio wave generation source) 130, a relay station controller (controller) 140 that centrally controls all the relay stations 130 installed in the management area 110, a transmission / reception device 150, a control device 160, and the like.

In this embodiment, the management area 110 is provided for raising birds such as a birdhouse. When the present invention is applied in addition to bird flu monitoring, the management area 110 may be an outdoor area such as a ranch, an indoor area such as a cowshed, or each animal in the zoo. It can be a building or a whole natural park. Furthermore, the configuration of the present invention can be applied even to a human subject.
In the management area 110, the sensor 120 and the relay station 130 communicate with each other wirelessly. Therefore, the management area 110 is an area where the relay station 130 can directly or indirectly acquire the signal from the sensor 120. Therefore, when the management area 110 is widened, the output of the wireless communication of the sensor 120 may be increased or the number of relay stations 130 may be increased. It is preferable that one relay station 130 can cover an area having a radius of several tens of meters. As a communication method between the sensor 120 and the relay station 130, there are standards such as IEEE 802.11x wireless LAN, PHS (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), and UWB. Considering the balance between power consumption and communication distance, ZigBee (registered trademark) can be said to be a suitable method at present. Of course, other methods may be used.

The sensor 120 is a system for monitoring the health state of a bird, which is a high-density integration of a sensor group that detects the posture, behavior, vital signs, and the like of a bird and a detection processing circuit, a communication circuit, a power source, and a power management device. It is a package.
Measurement data in the sensor 120 is transmitted wirelessly. The transmitted measurement data is received by the relay station 130 and further transferred to the relay station controller 140.
The relay station 130 and the relay station controller 140 can be connected by wireless or wired Ethernet (registered trademark). The relay station controller 140 controls not only the relay station 130 installed in the management area 110 but also the relay stations in the other management areas 112 and 114, and collects and transmits data of the sensors 120 received by these relay stations. Transfer to device 150. Further, in addition to collecting data from the relay station 130, the relay station controller 140 is assigned an identification mark such as an IP address to all the relay stations 130 installed in the management area 110, or from the control device 160. A function of mediating transmission of a command given to each sensor 120 can be added. In another embodiment, when a mesh network is formed by a plurality of relay stations 130, the relay station controller 140 may be configured to also control handover between the relay stations 130.
The transmission / reception device 150 transmits the measurement data of the sensor 120 to the control device 160 through Ethernet (registered trademark), the Internet, a telephone line, a wireless telephone network, or the like.

The control device 160 is a computer device in terms of hardware, and can be manufactured by installing software having necessary functions in a general-purpose computer. For this reason, many functions of the control device 160 are realized by the cooperation of hardware such as a CPU, memory, network adapter, and modem provided in a general computer and software.
The control device 160 monitors the occurrence of avian influenza by determining the measurement data transmitted from the sensor 120. If it is determined that the measurement data transmitted from the sensor 120 indicates the occurrence of avian influenza, the determination result, that is, information indicating that avian influenza has occurred, is output as an alarm, printed matter It is also possible to output by printing out, sending an e-mail to a destination input in advance, or the like. The control device 160 may be installed in the vicinity of the management area 110, but may be installed in a remote place that is completely separated.

  In the bird flu monitoring system 100, it is possible to monitor the behavior of many birds at low cost and online without interfering with the behavior of the bird by attaching the sensor 120 to the managed animal and wirelessly monitoring it. . This makes it possible to easily grasp the health status of birds to be managed, and to quickly detect emergencies such as the occurrence of infectious diseases.

Next, the configuration of the sensor 120 will be described with reference to FIG.
As shown in FIG. 2, the sensor 120 includes, for example, a physical quantity sensor 210 that measures a predetermined physical quantity on a thin film substrate, and a circuit that controls each unit so as to perform a predetermined operation as the sensor 120. A configured sensor control unit 220, a capacitor unit 230 that stores power necessary for the operation of the sensor 120, a communication control unit 240 for performing communication control for transmitting and receiving radio waves to and from the relay station 130, This is an ultra-small network sensor chip in which the antenna 250 is mounted on a thin-band (film-like) substrate.
Such a sensor 120 is miniaturized by making full use of the latest ultra-high density mounting technology and MEMS processing technology and narrowing down the sensor function. In one example, an ultra-small sensor chip is manufactured by a system-in-package in which a three-dimensional laminated chip (5 mm or less) is mounted in the middle 1 cm square region on a 3 cm square antenna FPC.

  The physical quantity sensor 210 is a physical quantity sensing chip that measures at least one of acceleration, inclination, temperature, blood flow, blood pressure, and pulse. In the present embodiment, as the physical quantity sensor 210, an acceleration sensor 210A and a temperature sensor 210T are provided.

  In the sensor 120 of the present embodiment, sensor information including acceleration information and temperature information detected by the acceleration sensor 210A and the temperature sensor 210T is not sequentially transmitted to the relay station 130, but the transmission frequency and the amount of transmission data are suppressed. Thus, the power consumption can be reduced.

  Specifically, the sensor control unit 220 includes an IC and a memory, and includes an event-driven circuit that performs predetermined processing when a signal is received from the physical quantity sensor 210. Here, as the predetermined process, there is a process of storing the contents of the signal received from the physical quantity sensor 210 in a memory.

  Further, in the present embodiment, the sensor 120 generates power by induced electromotive force by receiving the radio wave transmitted from the relay station 130 by the antenna 250 based on the control of the relay station controller 140, and this power is stored in the capacitor. The part 230 is stored. Therefore, the sensor control unit 220 includes an RF-DC conversion circuit that converts radio waves received by the antenna 250 into direct current, a charging circuit that stores electric power in the capacitor unit 230 by direct current converted by the RF-DC conversion circuit, It has. As described above, since the sensor 120 is an active sensor that is equipped with a power source and communicates with its own power, scanning by a reader is not required unlike RF-ID, and it is never easy to control its behavior. Suitable for bird management.

  The communication control unit 240 responsible for communication control exhibits a function as an ultra-small wireless communication device for transmitting a message including measurement data from the physical quantity sensor 210, and includes a control chip having a communication control circuit, An impedance matching circuit for matching the impedance of radio waves to be transmitted and received. Here, the control chip is configured to have a unique identifier. When transmitting sensor information from the physical quantity sensor 210, the control chip is configured to transmit the identifier together.

FIG. 3 is a diagram illustrating a configuration of an acceleration sensor 210 </ b> A for detecting acceleration in the physical quantity sensor 210.
As shown in FIG. 3, the acceleration sensor 210 </ b> A includes a deformation member 211 that deforms according to the acceleration applied to the acceleration sensor 210 </ b> A, a piezoelectric material unit 212 that generates an electric charge according to the deformation of the deformation member 211, and a piezoelectric material. And a signal processing circuit 213 to which a voltage obtained according to the amount of charge generated in the unit 212 is applied.

  Here, as the deformable member 211, for example, a cantilever type composed of a cantilever 211a and a weight 211b can be used. In the cantilever-type deformable member 211, when acceleration is applied, the cantilever 211a to which the mass of the weight 211b is added is bent and deformed with a deformation amount corresponding to the applied acceleration. Such a deformable member 211 is not limited to a cantilever type but may be another type such as a diaphragm type. Other types include, for example, a structure in which a weight is supported by a plurality of cantilevers (see Journal of Micromechanics and Microengineering, vol. 10, (2000) 322-328).

The piezoelectric material part 212 is made of a piezoelectric thin film formed on the surface of the deformable member 211. As a material for forming such a piezoelectric thin film, in addition to a PZT (lead zirconate titanate) material, a well-known piezoelectric material such as BaTiO ₃ , ZnO, AlN, quartz, PVDF (polyvinylidene fluoride), or the like can be used. It is. When the deformable member 211 is deformed according to the applied acceleration, the piezoelectric material part 212 generates electric charges according to the deformation amount. That is, the larger the applied acceleration, the larger the electric charge is generated in the piezoelectric material part 212. The voltage obtained in the piezoelectric material portion 212 is determined by the generated charge and the load capacity in the piezoelectric material portion 212.
Here, if the cantilever 211a is formed of, for example, a Si-based material, the piezoelectric material portion 212 may be formed by forming a thin film made of a predetermined piezoelectric material on the surface, and the cantilever 211a itself is made of a piezoelectric material. It is also possible to form the cantilever 211a itself as the piezoelectric material portion 212.
In addition to the piezoelectric thin film, the piezoelectric material portion 212 can employ a piezoelectric thick film, a material that bulk-bonds a piezoelectric body, or the like.

  A plurality of deformable members 211 having such a piezoelectric material part 212 are provided in the acceleration sensor 210A such that the piezoelectric material parts 212 are electrically connected in series, and one end side thereof is electrically grounded. .

The signal processing circuit 213 is a MoS (Metal Oxide Semiconductor) transistor having a circuit configuration as shown in FIG. This signal processing circuit 213 can be provided in an IC constituting the sensor control unit 220.
As shown in FIG. 3, a plurality of such signal processing circuits 213 are connected to different deformation members 211 with respect to the deformation members 211 connected in series. Here, the signal processing circuit 213 may be smaller than the number of the deformable members 211 connected in series, or may be connected to all the deformable members 211. In the present embodiment, for example, 40 deformable members 211 are provided in series, and a signal processing circuit 213 is connected to four deformable members 211 at positions previously extracted and selected.

A voltage from the piezoelectric material part 212 of the deformable member 211 to which the signal processing circuit 213 is connected is applied to the gate of the signal processing circuit 213. Here, since the piezoelectric material part 212 of the deformable member 211 is connected in series, the signal processing circuit 213 connected to the nth deformable member 211 from the ground side has a potential difference from the reference potential as the ground side. To the sum (n × V) of the voltages V generated in the n piezoelectric material portions 212 are applied.
Here, in each signal processing circuit 213, the voltage at which the transistor is turned ON is set in advance. That is, when the applied voltage exceeds the set voltage, the signal processing circuit 213 is turned on.
In the sensor control unit 220 to which the signal processing circuit 213 is connected, when the signal from the signal processing circuit 213 is switched from OFF to ON, or from ON to OFF, the switching from OFF to ON, or from ON to OFF, and Time information is stored in a memory, and the stored information is transmitted to the control device 160 via the relay station 130 at a predetermined timing.

  When acceleration acts on the acceleration sensor 210 </ b> A, the individual deformation members 211 are similarly deformed, and thus the same voltage is applied from each piezoelectric material part 212. At this time, in the signal processing circuit 213 connected to the deformable member 211 close to the ground side, since the number of piezoelectric material portions 212 connected from the ground side is small, the applied voltage is also small. On the other hand, in the signal processing circuit 213 connected to the deformable member 211 separated from the ground side, the number of piezoelectric material portions 212 connected from the ground side is large, so that the applied voltage increases.

  With such a configuration, the applied voltage varies depending on the applied acceleration, and therefore the acceleration can be digitally determined by recognizing which signal processing circuit 213 is turned on. That is, each signal processing circuit 213 has a function like a switch.

For example, studies by the present inventors have shown that the acceleration caused by bird movement is 0.05 g during sleep, 0.2 g cocoon, 0.5 g during meals, and 1 g during tremors.
Assuming that the sensitivity of the piezoelectric material portion 212 provided on the deformable member 211 is 1.1 mV / g, for example, when the sensor 120 is attached to a bird, the piezoelectric material portions 212 of the individual deformable members 211 are moved by the respective operations described above. As shown in Table 1, the output voltage of 0.055 mV, 0.22 mV, 0.55 mV, and 1.1 mV is output.

In the acceleration sensor 210A, for example, 40 deformation members 211 including the piezoelectric material portion 212 are connected in series, and n = 3rd, 10th, 15th, and 40th deformation from the ground side. When the signal processing circuit 213 is provided in the member 211, the voltage applied according to the bird's movement is as shown in Table 1.
When the voltage that is turned on in each signal processing circuit 213 is set to 2 mV, the signal processing circuit 213 that is turned on according to the operation of the bird is as shown in Table 1. That is, only the signal processing circuit 213 _{(n = 40)} attached to the n = 40th deformable member 211 is turned ON during sleep. The signal processing circuits 213 _{(n = 15)} and 213 _{(n = 40)} attached to the _{n = 15} , _40th deformable member 211 are turned on at the time of drought, and the n = 10, ₁₅ , _40th deformable member 211 is turned on at the meal. The signal processing circuits 213 _{(n = 10)} , 213 _{(n = 15)} , and 213 _{(n = 40)} attached to are turned on. When the body shakes, all signal processing circuits 213 _{(n = 3)} , 213 _{(n = 10)} , 213 _{(n = 15)} , 213 attached to the _{n = 3} , ₁₀ , ₁₅ , 40th deformable member 211 _{(N = 40)} is turned ON.

In this way, in the acceleration sensor 210A, the acceleration level can be obtained digitally according to the number of signal processing circuits 213 that are turned on. For example, as shown in Table 1, when the signal processing circuit 213 _{(n = 40)} is turned on, level 1 is set, and the signal processing circuits 213 _{(n = 15)} and 213 _{(n = 40)} are turned on. In the case of level 2, the signal processing circuit 213 _{(n = 10)} , 213 _{(n = 15)} , 213 _{(n = 40)} is turned on, and in level 3, the signal processing circuit 213 _{(n = 3)} , 213 _{( When n = 10)} , 213 _{(n = 15)} , and 213 _{(n = 40)} are turned on, the level 4 can be set.

FIG. 4 shows the voltage applied to each signal processing circuit 213 when the behavior of a bird is, for example, 15 minutes for a shark, 10 minutes for a meal, 30 minutes for sleep, and 5 minutes for a tremor. It shows the displacement over time. In this way, when trembling, which is an operation that can determine that an abnormality has occurred in the state of the bird, signal processing circuits 213 _{(n = 3)} , 213 _{(n = 10)} , 213 _{(n = 15) )} 213 _{(n = 40)} is turned ON, and the sensor control unit 220 can determine that the acceleration level is level 4.
In the sensor 120, sensor information is transmitted when the temperature detected by the temperature sensor 210T deviates from a preset range and is a value at which it can be determined that an abnormality has occurred in the state of the bird. Yes. That is, when the acceleration level is level 4 in the sensor control unit 220, the sensor 120 transmits a signal indicating that the detected acceleration level is level 4.
When receiving a signal indicating that the acceleration level is level 4 from the sensor 120, the control device 160 can determine that an abnormality has occurred in the physical condition of the bird in the management area 110.
In this case, all of the signal processing circuits 213 _{(n = 3)} , 213 _{(n = 10)} , 213 _{(n = 15)} , and 213 _{(n = 40)} may be monitored. However, in the sensor control unit 220, You may make it monitor the signal processing circuit 213 _{(n = 3)} turned ON only in the case of a tremor.

In such an acceleration sensor 210A, the piezoelectric material portion 212 made of a piezoelectric material directly generates electric charges due to the applied acceleration, so that power consumption during standby is almost zero.
Further, by providing the piezoelectric material portion 212 provided in the deformable member 211 in series, it is possible to increase the amount of power generated when acceleration is applied, so that the acceleration sensor 210A can be highly sensitive.
Furthermore, such an acceleration sensor 210A can be formed in a small size by the MEMS technology, and by reducing power consumption, it is possible to eliminate the battery and reduce the weight.
Here, of course, the sensitivity in the piezoelectric material part 212 and the number of deformation members 211 mentioned above, the set voltage that is turned on in the signal processing circuit 213, and the like are merely examples, and can be changed as appropriate. By changing the number of deformable members 211 provided with the piezoelectric material portions 212 provided in series, the connection position of the signal processing circuit 213, the set voltage in the signal processing circuit 213, and the like, various accelerations can be obtained in addition to birds. It becomes possible to measure. Also at this time, the individual deformable member 211, the piezoelectric material part 212, and the signal processing circuit 213 themselves can be used in common, so it is only necessary to change the design according to the use, and the device configuration has high versatility and applicability. It can be said that there is.

FIG. 5 is a diagram showing a configuration of a temperature sensor 210T for detecting the temperature in the physical quantity sensor 210. As shown in FIG.
As shown in FIG. 5, the temperature sensor 210T includes a plurality of bimetal cantilever sensors 221.
In the bimetal cantilever sensor 221, a lever (cantilever) 222 made of a bimetal material in a state where a high linear expansion coefficient material 222a and a low linear expansion coefficient material 222b are joined or laminated, and only a base end portion 222c thereof is fixed to the base 223. Thus, the structure is supported in a cantilever shape. An electrical contact member 224 made of a conductive material is disposed with a predetermined gap so as to face the lever 222.

As the high linear expansion coefficient material 222a constituting the lever 222, for example, Al (α = 23.1E-6 / ° C.), Au (α = 14.2E-6 / ° C.), Ni (α = 13.4E−) 6 / ° C.) can be used. Examples of the low linear expansion material 222b include W (α = 4.5E-6 / ° C.), Mo (α = 5.5E-6 / ° C.), and Invar alloy (α = 0.1E-6 / ° C.). Silicon (α = 2.5E-6 / ° C.), silicon oxide (α = 0.5E-6 / ° C.), silicon nitride (α = 3E-6 / ° C.), or the like can be used.
The lever 222 made of such a bimetal material is bent and deformed around the base end portion 222c according to a change in temperature due to the difference in linear expansion coefficient between the high linear expansion coefficient material 222a and the low linear expansion coefficient material 222b. When the distal end portion 222d moves in a direction approaching or separating from the electrical contact member 224 and reaches a predetermined temperature, the distal end portion 222d comes into contact with the electrical contact member 224.
Here, in the measurement at a temperature higher than room temperature, the low linear expansion coefficient material 222b is usually provided so as to face the electrical contact member 224, and constitutes an electrical contact with respect to the electrical contact member 224. For this reason, the low linear expansion coefficient material 222b needs to be formed of a conductive material. When a material other than metal is used as the low linear expansion coefficient material 222b, it is necessary to add a conductive member such as a wiring made of a conductive material to the surface of the lever 222 on the low linear expansion coefficient material 222b side.

In the bimetal cantilever sensor 221 provided in plurality, the lengths of the levers 222 are different from each other. If the high linear expansion coefficient material 222a and the low linear expansion coefficient material 222b constituting the lever 222 are common between the bimetal cantilever sensors 221, the lever 222 should be at the same distance from the base end portion 222c. For example, it bends and deforms with the same radius of curvature according to the temperature change. At this time, since the lengths of the levers 222 are different between the bimetal cantilever sensors 221, the longer the lever 222, the larger the displacement of the tip end portion 222d. Therefore, as the bimetallic cantilever sensor 221 having the longer lever 222, the tip end portion 222d contacts the electrical contact member 224 at an earlier timing. That is, in each bimetal cantilever sensor 221, the timing at which the tip end portion 222d contacts the electrical contact member 224, that is, the temperature, is determined according to the length of the lever 222.
Here, as will be described in detail later, the difference in the length of the lever 222 between the bimetal cantilever sensors 221 is determined by the measurement pitch when the temperature is measured digitally, in other words, the minimum unit of measurement. Accordingly, the length of the lever 222 between the bimetal cantilever sensors 221 is preferably provided at a constant dimensional pitch. The length of the lever 222 may be constant, and the gap between the lever 222 and the electrical contact member 224 may be different among the plurality of bimetal cantilever sensors 221.

In each bimetal cantilever sensor 221, a voltage is applied to the electrical contact member 224, and the lever 222 side is grounded.
A signal processing circuit 225 is connected to each bimetal cantilever sensor 221. In the signal processing circuit 225, the voltage stored in the capacitor (voltage application unit) 225a is applied to the electrical contact member 224. In the bimetal cantilever sensor 221, when the lever 222 is deformed due to a temperature change and is brought into conduction by contacting the electrical contact member 224, the voltage changes. This is detected by a detection circuit 225b comprising an F / F (Flip Flop) circuit. Detect with. When the voltage detected by the detection circuit 225b fluctuates, the output signal from the detection circuit 225b switches from OFF to ON or from ON to OFF.
Further, in the sensor control unit 220, when it is detected that the output signal from the detection circuit 225b has switched from OFF to ON, after a certain waiting time has elapsed (because the ON state continues when the temperature becomes high). The power supply control signal for supplying power from the power source to the capacitor 225a discharged by conduction between the lever 222 and the electrical contact member 224 for a certain time is output to the power source.
Such a signal processing circuit 225 can be formed in an IC constituting the sensor control unit 220.

In the temperature sensor 210T having such a configuration, a plurality of sets of bimetal cantilever sensors 221 are provided, and the lengths of the levers 222 are different in a plurality of stages. Thus, for example, when the temperature rises and reaches a predetermined temperature determined by the length of the lever 222 of each bimetal cantilever sensor 221, the lever 222 comes into contact with the electrical contact member 224 and the signal processing circuit 225 detects from the detection circuit 225b. Output signal is turned ON. Thereby, in the sensor control unit 220, for example, when the temperature rises continuously, the output signals of ON are sequentially output from the signal processing circuits 225 of each set in the order of the length of the lever 222. On the other hand, if the temperature decreases, the lever 222 that has been in contact with the electrical contact member 224 moves away from the electrical contact member 224, and the output signal from the detection circuit 225b is turned off. For this reason, in the sensor control unit 220, for example, when the temperature continuously decreases, output signals of OFF are sequentially output from the signal processing circuits 225 of each set in the order of the shortness of the lever 222.
Here, in the sensor control unit 220, when the signal from the detection circuit 225b is switched from OFF to ON, or from ON to OFF, the switching from OFF to ON or from ON to OFF and the time information thereof are stored in the memory. The stored information is transmitted to the control device 160 via the relay station 130 at a predetermined timing.

With such a configuration, the temperature change can be measured digitally by detecting the contact of the plurality of bimetallic levers 222 having different lengths to the electrical contact member 224 using a signal from the detection circuit 225b. It becomes possible. At this time, by appropriately setting the length difference of the levers 222 among the plurality of levers 222, it is possible to minimize the power consumption without detecting the temperature with the minimum unit / accuracy more than necessary. It can be. As long as the temperature change amount does not exceed a certain level, the lever 222 does not contact the electrical contact member 224 and no ON signal is output. Thereby, naturally, the power for outputting the signal can also be suppressed. Further, the data obtained as a result of the measurement in this way is the temperature and time information when the temperature change occurs. That is, if the temperature change is small, the amount of data transmitted wirelessly can be suppressed, which also leads to power saving.
Even during standby, power is stored in the capacitor 225a, and power is supplied to the capacitor 225a when the lever 222 comes into contact with the electrical contact member 224 and discharges. Can be suppressed. Furthermore, since the voltage fluctuation generated when the lever 222 contacts / separates from the electrical contact member 224 becomes the output signal from the detection circuit 225b as it is, a digital signal can be directly output, and an AD converter is unnecessary. .

Such a temperature sensor 210T can be formed by MEMS technology.
As shown in FIG. 6, a silicon oxide film 261 serving as a sacrificial layer is deposited on a silicon substrate 260, and Ni (Young's modulus 200 GPa) having a thickness of 0.5 μm is formed thereon as a high linear expansion coefficient material 222a. , Linear expansion coefficient 13.4E-6 / ° C.) The film 262 is formed by sputtering or vapor deposition. Further, a W (Young's modulus: 345 GPa, linear expansion coefficient: 4.5E-6 / ° C.) film 263 having a thickness of 0.5 μm is formed as a low linear expansion coefficient material 222b by sputtering or vapor deposition. Form. These films can be processed with an accuracy of μm level using photolithography and etching. 21 levers 222 having a length of 195 μm to 215 μm are manufactured by changing the length by 1 μm. By using photolithography and etching, a plurality of levers 222 having different lengths can be manufactured simultaneously.

Next, etching is performed with an HF aqueous solution to remove the silicon oxide film 261 at a lower portion of the lever 222 having the bimetal structure, so that the lever 222 can be freely operated. Since W and Ni do not dissolve in HF, the lever 222 can be left selectively.
A glass plate 264 having a recess 264a having a depth of 5 μm is joined to the upper surface of the lever 222, and an electrical contact member 224 is joined to the inside thereof. The glass plate 264 and the electrical contact member 224 may be obtained by joining two layers of an insulating spacer having a thickness of 5 μm and a substrate on which an electrode is formed.
The bimetal lever 222 is bent toward the electrical contact member 224 when the temperature rises because the W film 263 made of the low linear expansion coefficient material 222b faces the electrical contact member 224. Here, one end of a bimetal prepared by superposing two layers of material A (thickness ta, Young's modulus Ea, linear expansion coefficient αa) and material B (thickness tb, Young's modulus Eb, linear expansion coefficient αb) is fixed. When the cantilever structure has a length L, the displacement y due to the temperature change ΔT at the other end is expressed by the following equation. From this equation, the temperature difference that produces a displacement of 5 μm at the tip 222 d of the lever 222 can be calculated.

FIG. 7 shows a calculation result when the lever 222 has a length of 195 to 215 μm in the temperature sensor 210T having the above-described configuration using Equation 1.
When the lever 222 without bending at room temperature (20 ° C.) is manufactured, when the temperature difference shown in FIG. 7 occurs, the lever 222 and the electrical contact member 224 come into contact with each other and the switch is turned on. For example, the lever 215 μm in length is switched on at a temperature difference of 16.51 ° C. (actual temperature 36.51 ° C.) with respect to room temperature. The 21 levers 222 having different lengths can cover the actual temperature range of 36.51 ° C to 40.07 ° C at intervals of about 0.2 ° C. This corresponds to a response from normal human heat to heat generation, and by using this temperature sensor 210T, it becomes possible to measure the human body temperature with an accuracy (measurement pitch) of 0.2 ° C.
When the sensor 120 is used for another living body, the same design may be performed in the measurement temperature range corresponding to the type of the living body.

  Thus, the temperature sensor 210T can be reduced in size and weight by forming the temperature sensor 210T by the MEMS technology. In addition, the levers 222 and the like having different lengths can be formed in a lump, so that mass production is possible at a low cost. The sensor 120 provided with such a temperature sensor 210T can be reduced in size and weight, and can save power.

Now, as described above, such a sensor 120 generates electric power by induced electromotive force by receiving a radio wave transmitted from the relay station 130 by the antenna 250, and stores this electric power in the capacitor unit 230. ing. A telegram including the measurement data in the sensor 120 using the power stored in the capacitor unit 230 is transmitted wirelessly and received by the relay station 130. Here, in the sensor 120, the communication control unit 240 creates a message including information such as an identifier given to the control chip of the sensor 120 together with the measurement data to be transmitted, and transmits it to the relay station 130.
Further, the frequency of the radio wave transmitted from the relay station 130 for supplying power to the sensor 120 and the radio wave transmitted from the sensor 120 to the relay station 130 for transferring a message including measurement data are different from each other. Is set to

Here, in one relay station 130, power supply by radio waves and reception of a message including measurement data can be performed with respect to a plurality of sensors 120 existing within a range in which the relay station 130 can perform wireless communication. ing.
And from each sensor 120, the message | telegram containing measurement data is transmitted to the relay station 130 in the predetermined order and timing allocated to each sensor 120 beforehand. Here, it is conceivable to perform communication for requesting data transmission from each relay station 130 to each sensor 120. However, in this case, each sensor 120 receives communication from the relay station 130. Standby power is required. Therefore, by transmitting a message containing measurement data from each sensor 120 at a predetermined timing, the standby power can be suppressed. In order to do this, it is necessary to perform time correction in each sensor 120 to suppress an error in data transmission timing so that communication with one relay station 130 does not interfere among a plurality of sensors 120.
Therefore, in the present invention, the relay station controller 140 uses the radio wave transmitted from the relay station 130 to each sensor 120 for power supply, and transmits a command for time correction in each sensor 120. To do. That is, as shown in FIG. 8, in the relay station controller 140, the radio waves transmitted from the relay station 130 to the individual sensors 120 for power supply are stopped as a command at regular intervals. . For example, every time radio waves are transmitted for one hour, radio wave transmission is stopped for 0.01 seconds.

The sensor 120 receives the radio wave transmitted from the relay station 130 to supply power to the sensor 120 by the antenna 250. The sensor control unit 220 receives the time of the internal clock function when the radio wave is stopped. Correction is made.
By correcting the time in this way, even when a large number of sensors 120 are used, it is possible to avoid duplication of data transmission timing among the plurality of sensors 120, and the individual sensors 120 in a predetermined order and timing. A message including measurement data can be transmitted from the relay station 130 to the relay station 130. Thereby, in the sensor 120, the measurement data may be transmitted to the relay station 130 at a predetermined timing based on the clock function built in itself, and the standby power can be suppressed.

In each sensor 120, when a message including measurement data measured by the acceleration sensor 210A or the temperature sensor 210T is transmitted to the relay station 130, the transmission timing is a predetermined timing assigned to each sensor 120 as described above. At the timing of
FIG. 8 is a chart showing the timing at which a message including measurement data is transmitted to the relay station 130 in one sensor 120. As shown in FIG. 8, the sensors 120 are allocated such that a time zone Ts for transmitting a telegram including measurement data to the relay station 130 is in a predetermined order and timing. Time zones other than the time zone Ts are allocated to the other sensors 120.
In the time zone Ts allocated to the sensor 120, the start time T1 and the end time T2 are managed by the clock function of the sensor 120 as described above. Here, the time zone Ts is set to a length that can secure an error of the built-in clock that can occur even if time correction is performed, and a time for retransmitting data when transmission of a message including measurement data fails. It is preferable to do this.

The relay station controller 140 has a function of checking a message including measurement data transmitted from each sensor 120 and determining whether an error has occurred. When an error has occurred in the received electronic message, the relay station controller 140 transmits a command for requesting retransmission to the sensor 120 that transmitted the electronic message via the relay station 130. .
The command for requesting re-transmission of the message to the sensor 120 is included in the radio wave for supplying power transmitted from the relay station 130 to each sensor 120. For this purpose, under the control of the relay station controller 140, the radio wave for supplying the power transmitted from the relay station 130 to the sensor 120 that needs to retransmit the message within the range of the time zone Ts is stopped for a certain period of time. It is.
In the sensor 120, when the radio wave transmitted from the relay station 130 to the sensor 120 and received by the antenna 250 stops within the time zone Ts, the sensor control unit 220 measures the measurement data. A message containing is sent again.

  In this way, if there is an error in data transmission from each sensor 120, the error can be corrected and reliable data collection can be performed. In addition, when there is an error, a radio wave for supplying power to the sensor 120 is used, and by stopping the radio wave, a command for requesting retransmission of data is transmitted to the sensor 120. On the sensor 120 side, it is not necessary to enter a reception standby state in order to receive a command for a data re-transmission request, and standby power can be suppressed.

The acceleration sensor 210A and the temperature sensor 210T described above have a configuration like a digital switch, and can directly output a measurement result as digital data. In addition, an output indicating that a change has occurred is performed only when the change is greater than a certain amount.
FIG. 9A is an example of measurement data transmitted from the sensor 120 to the relay station 130. Here, FIG. 9B is an example of measurement data transmitted from the sensor 120 to the relay station 130 when the conventional sensor, that is, measurement data is transmitted at regular intervals. As shown in FIG. 9B, conventionally, measurement data such as measured temperature and acceleration are transmitted together with time information at regular intervals. Assuming that each data amount indicating time, temperature, and acceleration is 1 byte and measured every minute, the amount of data transmitted by one measurement is 3 bytes, and the amount of data transmitted in 10 minutes is 3 × 10 = 30 bytes.
On the other hand, in the case of the sensor 120, switch numbers may be given in advance to the individual signal processing circuits 213 and detection circuits 225b that function as switches in the acceleration sensor 210A and the temperature sensor 210T, for example, as shown in FIG. For example, as shown in FIG. 9A, the measurement data transmitted from the sensor 120 to the relay station 130 need only be information indicating a switch number that has changed more than a certain amount and time information at which the change has occurred. In other words, if no change has occurred, the ON / OFF state of the signal processing circuit 213 and the detection circuit 225b is not switched, so there is no need to transmit data. In the example corresponding to FIG. 9B, as shown in FIG. 9A, the data to be transmitted is only 2 bytes × 6 = 12 bytes in 10 minutes.
By doing so, the amount of data transmitted wirelessly can be suppressed, which also leads to power saving.

The preferred embodiments of the present invention have been described above by way of examples. However, the present invention can take various embodiments in addition to the embodiments described herein without departing from the scope thereof. Needless to say.
For example, the sensor 120 can be used for purposes other than monitoring the occurrence of avian influenza. In that case, the size, the type of sensor, the output of the communication device, etc. may be specially designed according to the use, such as for aquaculture, pastoral, and wild animals. If used for other purposes, the sensor 120 may be provided with a battery instead of supplying power by radio waves. Of course, the battery can be charged at an appropriate timing.
The present invention can be applied not only to the aquaculture industry, but also to other livestock farming and health monitoring of wild animals, and prevents large-scale transmission of infectious diseases via wild animals. It can also be used to construct a simple network.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

It is a conceptual diagram of the bird flu monitoring system in this Embodiment. It is a figure which shows the structure of a sensor. It is a figure which shows the specific structure of an acceleration sensor. It is a figure which shows the specific example of the voltage change in an acceleration sensor. It is a figure which shows the specific structure of a temperature sensor. It is an example of a structure in the case of manufacturing a temperature sensor by MEMS technology. It is a figure which shows the relationship between the length of a cantilever and an operating temperature difference. It is a figure which shows the transmission timing of the electromagnetic wave for supplying electric power to a sensor, and the timing which transmits the message | telegram containing measurement data from a sensor. (A) is an example of transmission data in the sensor in the present embodiment, (b) is an example of transmission data in the conventional sensor, and (c) is a diagram showing an example of switch assignment in the sensor of the present embodiment. is there.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Bird flu monitoring system (biological health management system), 120 ... Sensor, 130 ... Relay station (radio wave generation source), 140 ... Relay station controller (controller), 150 ... Transmission / reception device, 160 ... Control device, 210 ... Physical quantity 210A ... acceleration sensor 210T ... temperature sensor 211 ... deformable member 211a ... cantilever 211b ... weight 212 ... piezoelectric material part 213 ... signal processing circuit 220 ... sensor control part 221 ... bimetal cantilever sensor 222 ... Lever (cantilever), 222a ... High linear expansion coefficient material, 222b ... Low linear expansion coefficient material, 222c ... Base end, 222d ... Tip, 224 ... Electrical contact member, 225 ... Signal processing circuit, 225a ... Capacitor (voltage) Application unit), 225b ... detection circuit, 240 ... communication control unit, 250 ... Container

Claims (3)

A wireless sensor system comprising a plurality of sensors that measure a physical quantity and wirelessly transmit a telegram including measured measurement data, and a controller that receives the telegram from the sensor ,
The controller transmits a radio wave for supplying power to the sensor to a radio wave generation source, and stops the radio waves transmitted from the radio wave generation source to the plurality of sensors, thereby causing a command to the sensor. In the wireless sensor system that includes the radio wave ,
The plurality of sensors perform transmission of the message to the controller in a time zone assigned to each of the sensors in advance,
The wireless sensor system, wherein the controller includes, in the radio wave, a command for correcting the time of the time zone assigned to each of the plurality of sensors. The controller verifies the message transmitted from each of the plurality of sensors,
When there is an error in the telegram of verification, the radio of claim 1 in which a command requesting the retransmission of the message to the sensor that transmitted the message, characterized in that included in the radio wave Type sensor system. A system for managing the health of a living body,
A plurality of sensors that are respectively attached to a plurality of living bodies that perform management and measure a predetermined physical quantity, and wirelessly transmit a telegram including the measured measurement data,
A controller that receives the telegram from the sensor;
A radio wave source that transmits radio waves for supplying power to the sensor;
A determination device that determines whether an abnormality has occurred in the health state of the living body based on the measurement data included in the electronic message received by the controller;
In the wireless biological health management system , the controller includes a command for the sensor in the radio wave by stopping the radio wave transmitted from the radio wave generation source to the plurality of sensors.
The plurality of sensors perform transmission of the message to the controller in a time zone assigned to each of the sensors in advance ,
The wireless biological management system, wherein the controller includes, in the radio wave, a command for performing time correction of the time zone allocated to each of the plurality of sensors .