JP6004095B2 - Wireless sensor system - Google Patents

Description

  The present invention includes a resonance tag that generates and wirelessly transmits a resonance signal corresponding to a physical quantity of a measured part, and a reader module that receives the resonance signal and measures the physical quantity of the measured part from the frequency of the resonance signal. The present invention relates to a wireless sensor system.

  2. Description of the Related Art Conventionally, various wireless sensor systems that detect the physical quantity of a measurement target part using radio have been devised. For example, the wireless sensor system described in Patent Document 1 includes an RFID tag and a remote detection device.

  The RFID tag includes a resonator, and a reverberation signal is generated when the resonator is excited by a transmission signal from a remote detection device. The frequency of the reverberation signal is a frequency corresponding to the temperature of the measurement target part where the RFID tag is arranged. The remote detection device detects the temperature of the part to be measured by receiving the reverberation signal and performing frequency analysis.

  In such a wireless sensor system, a plurality of RFID tags may be used. In this case, when a transmission signal for excitation is transmitted to a plurality of RFID tags at the same time, each RFID tag transmits a reverberation signal. When the reverberation signal of each RFID tag has the same frequency, the remote detection device cannot identify the reverberation signal transmitted from which RFID tag.

  Therefore, in the wireless sensor system described in Patent Document 1, the frequency of the reverberation signal is different for each RFID tag.

JP 2011-180799 A

  However, in the wireless sensor system described in Patent Document 1, since the frequency must be different for each RFID tag, the frequency band for communication becomes wider as the number of RFID tags increases. In order to cope with such a frequency band, an antenna having a high gain in a wide frequency band and a plurality of antennas for covering a wide frequency band must be prepared. As a result, the remote sensing device becomes large or expensive, and practical use is not easy.

  Therefore, an object of the present invention is to provide a wireless sensor system that can individually receive a reverberation signal from an RFID tag (resonance tag) without being affected by the number of RFID tags (resonance tags).

  The wireless sensor system of the present invention includes a resonance tag and a reader module. The resonance tag includes a resonator whose resonance frequency changes according to a surrounding physical quantity and an RFID. The reader module includes a measurement signal receiving unit, a measurement unit, and an RFID communication control unit. The measurement signal transmission / reception unit transmits an excitation signal for exciting the resonator and receives a reverberation signal based on the excitation signal. The measurement unit measures a physical quantity based on the reverberation signal obtained by the measurement signal transmission / reception unit. The RFID communication control unit communicates with the RFID. The RFID communication control unit transmits an enabling command for enabling the resonator to the RFID. When the RFID obtains an activation command, the RFID activates resonance by the excitation signal of the resonator.

  In this configuration, the resonators of all the resonance tags can be invalidated in a steady state, and the resonators of the resonance tags from which the reverberation signal is acquired can be validated at the measurement timing. Thereby, only the reverberation signal from the resonator of the resonance tag from which the reverberation signal is to be acquired can be received by the reader module.

  The wireless sensor system of the present invention preferably has the following configuration. The RFID communication control unit transmits an invalidation command for invalidating the resonator to the RFID when the resonator is valid. When the RFID acquires the invalidation command, the RFID invalidates the resonance caused by the excitation signal of the resonator.

  In this configuration, the resonator of the resonance tag that was the measurement target can be invalidated at a designated timing. This prevents the resonator from being enabled unnecessarily long.

  The wireless sensor system of the present invention preferably has the following configuration. The RFID includes a switch circuit connected in parallel to the resonator. The switch circuit is in an open state when enabled and in a conductive state when disabled.

  In this configuration, switching between enabling and disabling of the resonator can be realized with a simple circuit configuration.

  The wireless sensor system of the present invention preferably has the following configuration. The RFID includes a storage unit that stores an operation program of the reader module. The RFID communication control unit acquires an operation program and sets operations of the RFID communication control unit, the measurement signal transmission / reception unit, and the measurement unit.

  In this configuration, the reader module is operated by the operation program stored in the RFID of the resonance tag. Therefore, a general-purpose reader module can be realized for various types of resonance tags.

  According to this invention, the reverberation signal from the resonance tag can be individually received, and the physical quantity such as the temperature of the measurement target part can be reliably measured.

1 is a configuration diagram of a wireless sensor system according to a first embodiment of the present invention. It is a block diagram of the resonance tag which concerns on the 1st Embodiment of this invention. It is a flowchart of the wireless sensor system which concerns on the 1st Embodiment of this invention. It is a figure which shows the case where a human body temperature is measured using the wireless sensor system which concerns on the 1st Embodiment of this invention. It is a block diagram of the wireless sensor system which concerns on the 2nd Embodiment of this invention. It is a flowchart of the wireless sensor system which concerns on the 2nd Embodiment of this invention.

  A wireless sensor system according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a wireless sensor system according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of the resonance tag according to the first embodiment of the present invention.

  The wireless sensor system 10 includes a resonance tag 20 and a reader module 30. The resonance tag 20 is attached to the part to be measured. The reader module 30 has a shape that can be carried by a measurer, for example.

  As illustrated in FIGS. 1 and 2, the resonance tag 20 includes an RFID 21, an RFID communication antenna 22, a resonator 23, and a resonator antenna 24. The reader module 30 includes an RFID communication control unit 31, an RFID communication antenna 32, a measurement signal transmission / reception unit 33, a measurement signal antenna 34, a measurement unit 35, and a display unit 36.

(Configuration of resonance tag 20)
The RFID 21 includes a control unit 211 and a resonance operation control unit 212.

  The controller 211 controls wireless communication with the outside using the RFID communication antenna 22. The control unit 211 communicates with the RFID communication control unit 31 of the reader module 31 via the RFID communication antenna 22 and the RFID communication antenna 32 of the reader module 31. Specifically, the control unit 211 receives the operation control signal Sc from the RFID communication control unit 31. The operation control signal is an enabling command Sce or an invalidating command Sci. The control unit 211 transmits the RFID identification information Sinf of the RFID 21 to the RFID communication control unit 31. The control unit 211 analyzes the operation control signal Sc and controls the operation of the resonance operation control unit 212.

  The resonance operation control unit 212 activates or deactivates the resonator 23 in response to the operation control from the control unit 211. Specifically, as shown in FIG. 2, the resonance operation control unit 212 is a switch circuit, and is connected in parallel to the resonator 23. The resonance operation control unit 212 including such a switch circuit is opened or turned on by operation control.

  The resonator 23 is an element whose resonance frequency changes according to the sensed temperature. For example, the resonator 23 is made of a crystal resonator. When the resonator 23 receives the excitation signal SpL via the resonator antenna 24, the resonator 23 resonates at a resonance frequency corresponding to the sensed temperature and generates a reverberation signal Sfp. Therefore, since the resonance tag 20 is attached to the measurement target, the resonator 23 resonates at a resonance frequency corresponding to the temperature of the measurement target, and generates a reverberation signal Sfp. That is, the frequency of the reverberation signal Sfp depends on the temperature of the part to be measured. Note that the resonator 23 may be an element whose resonance frequency changes according to a surrounding physical quantity such as magnetism or strain, not the sensed temperature.

  With such a configuration, the resonance tag 20 has the resonator 23 enabled by the operation control signal, and generates the reverberation signal Sfp when it receives the excitation signal SpL and transmits it from the resonator antenna 24 to the outside. To do. On the other hand, if the resonator 23 is disabled, the resonance tag 20 cannot generate the reverberation signal Sfp even if it receives the excitation signal SpL. Therefore, the resonance tag 20 does not transmit any signal from the resonator antenna 24 to the outside.

(Configuration of reader module 30)
The RFID communication control unit 31 communicates with the control unit 211 of the RFID 21 of the resonance tag 20 via the RFID communication antenna 32 and the RFID communication antenna 22 of the resonance tag 20. Specifically, the RFID communication control unit 31 transmits an operation control signal Sc to the control unit 211 of the RFID 21. The RFID communication control unit 31 receives and demodulates the RFID identification information Sinf from the control unit 211 of the RFID 21. By this process, the RFID 21 in communication, that is, the resonance tag 20 is identified.

  The RFID communication control unit 31 outputs transmission information of the operation control signal Sc to the measurement signal transmission / reception unit 33. The RFID communication control unit 31 outputs the acquired RFID identification information Sinf to the measurement signal transmission / reception unit 33.

  The measurement signal transmitting / receiving unit 33 generates the excitation signal SpL at a preset time interval and transmits it from the measurement antenna 34. The measurement signal transmitting / receiving unit 33 may generate the excitation signal SpL after detecting that the operation control signal Sc of the validation command Sce has been received. Thus, if the excitation signal SpL is generated and transmitted after receiving the detection of the validation command Sce, unnecessary transmission of the excitation signal SpL can be suppressed.

  When receiving the reverberation signal Sfp via the measurement antenna 34, the measurement signal transmission / reception unit 33 performs frequency analysis of the reverberation signal Sfp and acquires the frequency fp of the reverberation signal Sfp. The measurement signal transmitting / receiving unit 33 outputs the frequency fp of the reverberation signal Sfp to the measurement unit 35. The measurement signal transmission / reception unit 33 associates the RFID identification information Sinf with the frequency fp and outputs it to the measurement unit 35.

  The measuring unit 35 stores a relationship table between the frequency fp and the temperature T in advance. When obtaining the frequency fp, the measuring unit 35 refers to the relationship table and calculates the temperature T. At this time, the measurement unit 25 can determine a relation table based on the RFID identification information Sinf, and can calculate the temperature T from the determined relation table.

  The display unit 36 acquires and displays the temperature T calculated by the measurement unit 35. At this time, the display unit 36 may display the RFID identification information Sinf together with the temperature T. The display unit 36 can be omitted as necessary. In this case, an output terminal that outputs the temperature T and RFID identification information Sinf to the outside may be provided.

  The wireless sensor system 10 having such a configuration measures the temperature T of the measurement target part according to the following flow. FIG. 3 is a flowchart of the wireless sensor system according to the first embodiment of the present invention.

  The resonance tag 20 is attached to the part to be measured. In this state, the switch circuit which is the resonance operation control unit 212 is in a conductive state, and the resonator 23 is in an invalid state (S101).

  The reader module 30 is activated (S201). In a state where the reader module 30 is brought close to the resonance tag 20, a measurement start operation input is performed on the reader module 30. In response to the measurement start operation input, the reader module 30 transmits an validation command Sce (operation control signal Sc) (S202). Communication between the reader module 30 and the resonance tag 20 at this time is performed by, for example, so-called short-range non-contact communication.

  The resonance tag 20 maintains the invalid state until the validation command Sce is received (S102: NO). When the resonance tag 20 receives the validation command Sce (S102: YES), the resonance tag 20 switches the resonator 23 to the valid state (S103). Specifically, the switch circuit which is the resonance operation control unit 212 is opened.

  At this time, the resonance tag 20 transmits the RFID identification information Sinf to the reader module 30. The reader module 30 receives and demodulates the RFID identification information Sinf (S203).

  The reader module 30 generates and transmits an excitation signal SpL (S204). The resonator 23 of the resonance tag 10 receives the excitation signal SpL, resonates, and generates a reverberation signal Sfp (S103).

  The reader module 30 receives the reverberation signal Sfp (S205). The reader module 30 analyzes the frequency fp of the reverberation signal Sfp and measures the temperature T from the frequency fp (S206).

  The reader module 30 transmits an invalidation command Sci (operation control signal Sc) (S207).

  The resonance tag 20 maintains the valid state until the invalidation command Sci is received (S104: NO). When the resonance tag 20 receives the invalidation command Sci (S104: YES), the resonance tag 20 switches the resonator 23 to an invalid state (S105). Specifically, the switch circuit which is the resonance operation control unit 212 is turned on.

  By performing such configuration and processing, the reverberation signal Sfp can be generated only by the resonance tag 10 that is the measurement target. For example, even if there are a plurality of resonance tags within a range where the excitation signal SpL of the reader module 30 can reach, only the resonance tag 10 whose resonator is enabled by RFID communication generates the reverberation signal Sfp that responds to the excitation signal SpL. Can be generated. As a result, the reverberation signals Sfp from a plurality of resonance tags can be individually acquired without changing the frequency for each resonance tag. Therefore, it is possible to reliably measure a physical quantity such as a desired temperature of the measured part.

  Further, if the configuration and processing of this embodiment are used, the activation and invalidation of the resonator can be controlled by opening and conducting the switch circuit. Thereby, the resonance tag which has the above-mentioned operation effect can be realized with a simple configuration.

  In this embodiment, since the resonance tag 20 can be reduced in size, the wireless sensor system 10 can be used as follows. FIG. 4 is a diagram showing a case where the body temperature of a person is measured using the wireless sensor system according to the first embodiment of the present invention. However, FIG. 4 shows an example in which only two resonance tags 20 exist for the sake of explanation.

  As shown in FIG. 4, the RFID communication antenna 22 and the resonance antenna 24 are each realized by forming a coil electrode on a flexible thin flexible substrate (for example, paper and PET). ing. A resonator 23 is disposed at the end of the long portion 26 of the flexible substrate.

  When measuring the body temperature of a person, first, the resonator 23 of the resonance tag 20 is attached to the armpit 901 of the person 900 that is the test body, that is, the axilla 901. Next, the long portion 26 is wound around the upper arm 900A of the person 900 to fix the resonance tag 20 to the upper arm 900A. Thereby, the wireless sensor system 10 measures the deep body temperature of the person 900.

  When winding the long portion 26 around the upper arm 900A, the winding direction is adjusted so that the surface on which the coil electrode for realizing the RFID communication antenna 22 and the resonance antenna 24 is formed is outside (outside the upper arm 900A). To do. Thereby, RFID communication and transmission / reception of the excitation signal SpL and the reverberation signal Sfp can be performed between the reader module 30 and the resonance tag 20.

  In the example shown in FIG. 4, the reader module 30 activates only the resonator 23 of the resonance tag 20 attached to the person 900 with the enable command Sce, and invalidates the resonator 23 of the resonance tag 20 attached to the person 910. Yes. Therefore, the reader module 30 does not need to change the frequency for each resonance tag 20 even when the two resonance tags 20 exist within the range where the excitation signal SpL can reach, and the reverberation signal is transmitted only from the resonance tag 20 attached to the person 900. Sfp can be acquired.

  Next, a wireless sensor system according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a configuration diagram of a wireless sensor system according to the second embodiment of the present invention.

  The wireless sensor system 10A according to the present embodiment includes a resonance tag 20A and a reader module 30A. The resonance tag 20A includes an RFID 21A, an RFID communication antenna 22, a resonator 23, and a resonator antenna 24. The configuration of the RFID 21A is different from the RFID 21 according to the first embodiment, and the other configuration of the resonance tag 20A is the same as that of the resonance tag 20 according to the first embodiment. The reader module 30A includes an RFID communication control unit 31A, an RFID communication antenna 32, a measurement signal transmitting / receiving unit 33, a measurement signal antenna 34, a measurement unit 35A, and a display unit 36. The configuration of the RFID communication control unit 31A and the measurement unit 35A is different from the RFID communication control unit 31 and the measurement unit 35 according to the first embodiment, and the other configuration of the reader module 30A is the reader module 30 according to the first embodiment. Is the same. Therefore, only different parts will be described.

  The RFID 21A includes a control unit 211, a resonance operation control unit 212, and a storage unit 213. The basic configurations of the control unit 211 and the resonance operation control unit 212 are the same as those of the RFID 21 according to the first embodiment.

  The storage unit 213 stores a reader module operation program. The reader module operation program is, for example, a program for performing communication processing unique to the RFID 21A. The program also includes a relationship table that represents the resonance frequency of the resonator of the resonance tag 20A and the temperature characteristics of the resonance frequency.

  When receiving the program read command Scr from the RFID communication control unit 31A of the reader module 30A, the RFID 21A reads the operation program from the storage unit 213 and converts it into a radio signal. The RFID 21A outputs the operation program Spro converted into a radio signal to the RFID communication unit 31A. In addition, if the communication protocol of the read command Scr and the operation program Spro converted into a radio signal is a general-purpose protocol that does not depend on the type of RFID, the communication of the read command Scr and the operation program Spro converted into a radio signal can be reliably performed. Can be executed.

  The RFID communication control unit 31A transmits a read command Scr, receives the operation program Spro converted into a radio signal, and demodulates the operation program. The RFID communication control unit 31A sets the operation of the RFID communication control unit 31A itself and the operation of the measurement unit 35A from the demodulated operation program. The operation setting of the RFID communication control unit 31A itself is, for example, a communication protocol setting for the RFID 21A thereafter. The operation setting of the measurement unit 35A is a setting of a relation table for calculating the temperature T from the frequency fp corresponding to the resonator 23 attached to the resonance tag 20A.

  The measurement unit 35A measures the temperature T based on the setting by the operation program. Specifically, the measurement unit 35A calculates the temperature T from the relationship table set by the operation program and the frequency fp analyzed by the measurement signal transmission / reception unit 33.

  FIG. 6 is a flowchart of the wireless sensor system according to the second embodiment of the present invention. The flow of the wireless sensor system 10A of the present embodiment is the same as the flowchart of the wireless sensor system according to the first embodiment after the process of transmitting the validation command Sce. In addition, the same step numbers are given to the same processing portions as those in the flowchart of the wireless sensor system according to the first embodiment, and the description of the same processing portions is omitted.

  The reader module 30A is activated (S201). In a state where the reader module 30A is brought close to the resonance tag 20A, a read command Scr is transmitted to the resonance tag 20A (S221).

  When the resonance tag 20A receives the read command Scr (S121), the resonance tag 20A transmits the operation program Spro to the reader module 30A (S122). When receiving the operation program Spro (S222), the reader module 30A demodulates and develops the operation program Spro (S223). In the following, measurement processing is performed as in the first embodiment.

  By using such a configuration and processing, the reader module can reliably communicate for each resonance tag even if the communication specifications and the like are different for each resonance tag. That is, the reader module can be generalized. In addition, by including the relation table in the operation program Spro, the physical quantity can be accurately measured regardless of which resonance tag is used.

10, 10A: Wireless sensor system 20, 20A: Resonance tags 21, 21A: RFID
211: Control unit 212: Resonance operation control unit 213: Storage unit 22: RFID communication antenna 23: Resonator 24: Resonator antenna 30, 30A: Reader module 31: RFID communication control unit 32: RFID communication antenna 33: Measurement signal transmitter / receiver 34: measurement antenna 35, 35A: measurement unit 36: display unit

Claims (4)

A resonance tag including a resonator and an RFID whose resonance frequency changes according to a surrounding physical quantity; and
A measurement signal transmission / reception unit that transmits an excitation signal for exciting the resonator and receives a reverberation signal based on the excitation signal, and a measurement unit that measures a physical quantity based on the reverberation signal obtained by the measurement signal transmission / reception unit A reader module including an RFID communication control unit that communicates with the RFID;
With
The RFID communication control unit transmits an enabling command for enabling the resonator to the RFID,
When the RFID receives the activation command, the RFID activates resonance by the excitation signal of the resonator. The RFID communication control unit transmits an invalidation command for invalidating the resonator to the RFID when the resonator is activated,
The wireless sensor system according to claim 1, wherein when the RFID receives the invalidation command, the RFID invalidates resonance due to the excitation signal of the resonator. The RFID is
A switch circuit connected in parallel to the resonator;
The switch circuit is in an open state when enabled, and in a conductive state when disabled.
The wireless sensor system according to claim 1 or 2. The RFID is
A storage unit for storing an operation program of the reader module;
The RFID communication control unit acquires the operation program and sets the operation of the RFID communication control unit, the measurement signal transmission / reception unit, and the measurement unit.
The wireless sensor system according to any one of claims 1 to 3.

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