JP2010140270A - Sensing system, rfid tag, and sensing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a sensing system, which includes a reader-writer and an RFID tag, to obtain sensing data at a place where an electromagnetic wave from the reader-writer hardly reaches by stable radio communication. <P>SOLUTION: The sensing system includes a sensor 30, sensor 40, reader-writer 1, RFID tag 10 and RFID tag 20. Each sensor receives power supply through each power supply cable, and outputs sensing data through each communication cable. The reader-writer 1 includes a communicating part 2, the RFID tag 10 includes a storing part 14 for storing electromotive force caused by an electromagnetic wave transmitted from the communicating part 2, and feeding the power to each sensor, a control part 13 for acquiring the sensing data from each sensor, and a communicating part 12 for transmitting the obtained sensing data to the reader-writer, and the RFID tag 20 includes the same configuration as that of the RFID tag 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sensing system, an RFID tag, and a sensing device that acquire sensing data via an RFID tag.

  In recent years, an active RFID (Radio Frequency IDentification) tag with a built-in power supply, or a passive RFID tag that is activated using an electromotive force generated by an electromagnetic wave transmitted from an external reader / writer without a built-in power supply, has a built-in sensor. These RFID tags with sensors provided in advance send the sensing data (Sensing Data) such as the identification information and temperature of the product to the reader / writer by electromagnetic waves, so that the reader / writer acquires the sensing data without contact. This technology is used for logistics management and food production history management.

These conventional RFID tags with a sensor are installed in a range where electromagnetic waves reach with sufficient intensity from a movable reader / writer, and are used for sensing the installation range (for example, see Non-Patent Document 1).
“In the hands of consumers with fresh sake from Kuramoto,” [online], March 9, 2006, NTT DATA Corporation, [November 28, 2008 search], Internet <URL: http://www.nttdata.co.jp/release/2006/030900.html>

  However, for example, when sensing the underground using a conventional active RFID tag, the communication electromagnetic wave with the reader / writer on the ground is abruptly attenuated in the ground, so the communication with the RFID tag with a sensor in the ground is stable. There is a problem that sensing in the ground becomes difficult. In addition, when sensing the underground using a conventional passive RFID tag, for example, the electromagnetic force from the reader / writer on the ground is abruptly attenuated in the ground. Cannot be obtained from electromagnetic waves, which makes it difficult to sense underground.

  The present invention has been made in view of the above-described points. Sensing data including a reader / writer and an RFID tag in a place where an electromagnetic wave from the reader / writer is difficult to reach or a reader / writer user cannot access. Is obtained through stable wireless communication.

The present invention includes a sensor, an information terminal, and an RFID tag. The sensor is supplied with power through a power supply cable and outputs sensing data through a communication cable. The information terminal wirelessly communicates with electromagnetic waves. The RFID tag includes a first wireless communication unit that executes
A first power storage unit that stores an electromotive force generated by an electromagnetic wave transmitted from the first wireless communication unit of the information terminal and supplies power to the sensor via the power supply cable; and A sensing data acquisition unit for acquiring the sensing data from a sensor;
And a second wireless communication unit that performs wireless communication with the information terminal and transmits the acquired sensing data.

  The present invention also includes an information terminal, a sensing device, and a plurality of RFID tags. The information terminal includes a first wireless communication unit that performs wireless communication using electromagnetic waves, and the RFID tag includes the information tag. Sensing data acquisition for storing the electromotive force generated by the electromagnetic wave transmitted from the first wireless communication unit of the terminal, acquiring the sensing data via the communication cable, and the second power storage unit supplying power via the power supply cable A second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal, and an electromotive force data output unit that outputs data of an electromotive force generated in the second power storage unit, The sensing device includes a plurality of sensors connected to the plurality of RFID tags via the power supply cable and the communication cable, and outputs the sensing data. The electromotive force data acquisition unit that acquires the electromotive force data from the electromotive force data output unit included in the RFID tag, and the second power storage in which the maximum electromotive force is generated by comparing the size of the acquired electromotive force A third power storage unit that supplies power to the second power storage unit with power supplied from other than the second power storage unit in response to an instruction from the sensing device control unit. A sensing data output unit that outputs the sensing data to the sensing data acquisition unit included in the RFID tag including the second power storage unit.

  The present invention also includes an information terminal, a plurality of RFID tags, and a sensing device. The information terminal includes a first wireless communication unit that performs wireless communication using electromagnetic waves. The RFID tag includes the information terminal. A fourth power storage unit that stores an electromotive force generated by an electromagnetic wave transmitted from the first wireless communication unit of the terminal and feeds the stored electromotive force and power supplied via a power supply cable. A sensing data acquisition unit that acquires sensing data via a communication cable, a second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal, and the fourth power storage unit of the own RFID tag. An electromotive force data output unit for outputting generated electromotive force data to another RFID tag, and an electromotive force for acquiring electromotive force data generated in the fourth power storage unit included in the other RFID tag Compare the magnitude of the electromotive force based on the acquired electromotive force data with the data acquisition unit, and output a sensing data notification request when the fourth power storage unit of the own RFID tag shows the maximum electromotive force An RFID tag control unit that controls the fourth power storage unit of its own RFID tag to supply power to the fourth power storage unit when the fourth power storage unit of another RFID tag exhibits the maximum electromotive force; The sensing device is connected to the plurality of RFID tags via the power supply cable and the communication cable, and is supplied with power from the sensor that outputs the sensing data and the fourth power storage unit, A sensing device comprising: a fifth power storage unit that supplies power to the sensor; and a sensing data output unit that outputs the sensing data in response to the sensing data notification request. Is Gushisutemu.

  The present invention also stores an RFID tag power storage unit that stores an electromotive force generated by an electromagnetic wave transmitted from a first wireless communication unit of an information terminal and supplies power via a power supply cable, and obtains sensing data via a communication cable. A sensing data acquisition unit, a second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal, an electromotive force data output unit that outputs data of an electromotive force generated in the RFID tag power storage unit, An RFID tag comprising:

  The present invention compares the magnitude of the acquired electromotive force with the sensor that outputs sensing data, the electromotive force data acquisition unit that acquires electromotive force data from a plurality of RFID tags, and the maximum electromotive force is generated. A sensing device control unit that instructs to supply power to the RFID tag power storage unit, and a sensing device power supply that supplies power supplied from other than the RFID tag power storage unit to the RFID tag power storage unit in response to an instruction from the sensing device control unit A sensing data output unit that outputs the sensing data to the RFID tag including the RFID tag power storage unit.

  The present invention also stores an electromotive force generated by an electromagnetic wave transmitted from the first wireless communication unit of the information terminal, and supplies the stored electromotive force and the power supplied via a power supply cable. An RFID tag power storage unit, a sensing data acquisition unit that acquires sensing data via a communication cable, a second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal, and the RFID tag of its own RFID tag An electromotive force data output unit that outputs data of electromotive force generated in the power storage unit to another RFID tag, and an electromotive force data acquisition unit that acquires data of electromotive force generated in the RFID tag power storage unit included in the other RFID tag And when the magnitude of the electromotive force is compared based on the acquired electromotive force data, and the RFID tag power storage unit of the own RFID tag shows the maximum electromotive force RFID that outputs a sensing data notification request and controls the RFID tag power storage unit of its own RFID tag to supply power to the RFID tag power storage unit when the RFID tag power storage unit of another RFID tag shows the maximum electromotive force And a tag control unit.

  According to the present invention, one or more passive RFID tags are disposed at a distance where electromagnetic waves from a reader / writer reach with sufficient strength, and are connected by the passive RFID tag, a communication cable, and a power supply cable, and are separated from each other. Since the sensing is performed using one or more sensors installed in the mobile phone, stable wireless communication can be ensured by bringing the reader / writer close to the passive RFID tag and receiving strong electromagnetic waves. Moreover, it becomes a sensing system which can sense a wide range using one or more sensors installed in a distant place. Here, if wireless communication is performed from a plurality of RFID tags, multiple communication paths are provided, so that communication with the reader / writer can be performed more reliably.

  In addition, since one or more passive RFID tags feed the electromotive force generated by electromagnetic waves transmitted from the reader / writer to one or more sensors installed at remote locations via cables, the built-in power supply was used. The sensing system can perform sensing for a long time compared to the conventional active RFID tag.

  In addition, an RFID tag that is expected to be able to communicate stably with the reader / writer among a plurality of RFID tags is selected, and only the selected RFID tag performs wireless communication with the reader / writer and is not selected. RFID tags that do not perform wireless communication feed their own power to RFID tags that are performing wireless communication. Therefore, power is efficiently collected by collecting power in necessary blocks, and stable communication is performed. It becomes a sensing system that can.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
A first embodiment for carrying out the present invention will be described. FIG. 1 is a block diagram of a sensing system including an RFID tag according to the first embodiment of the present invention. The sensing system includes a reader / writer 1, an RFID tag 10, an RFID tag 20, a sensor 30, and a sensor 40. For example, it is assumed that the reader / writer 1 is disposed on the ground, the RFID tag 10 and the RFID tag 20 are installed on the ground surface, and the sensor 30 and the sensor 40 are embedded in the ground. In addition, the number of each block with which the said sensing system is provided does not need to be restricted to the number shown by FIG.

  The reader / writer 1 is an information terminal, and reads sensing data output from the sensor 30 and the sensor 40 by wirelessly communicating with each RFID tag. Further, the reader / writer 1 transmits electromagnetic waves to each RFID tag, and the RFID tag that has received the electromagnetic waves generates an electromotive force by itself, thereby supplying power to the RFID tag and the sensor connected to the RFID tag. Supply. The reader / writer 1 includes an antenna 4, a communication unit 2, and a control unit 3.

  The antenna 4 transmits electromagnetic waves to the antenna 11 and the antenna 21 in accordance with the drive from the communication unit 2. The antenna 4 receives electromagnetic waves from the antenna 11 of the RFID tag 10 and the antenna 21 of the RFID tag 20, and outputs a signal corresponding to the received electromagnetic waves to the communication unit 2.

  The communication unit 2 demodulates a signal corresponding to the electromagnetic wave received by the antenna 4 and outputs the signal to the control unit 3 as communication data. In addition, the communication unit 2 performs modulation processing according to an instruction from the control unit 3 and drives the antenna 4. The control unit 3 receives communication data from the communication unit 2 and acquires sensing data included in the communication data. The control unit 3 instructs the communication unit 2 to drive the antenna 4.

  A communication cable 31 is connected to the sensor 30. The sensor 30 outputs sensing data to the control unit 13 of the RFID tag 10 via the communication cable 31. Similarly, a communication cable 32 is connected to the sensor 30. The sensor 30 outputs sensing data to the control unit 23 of the RFID tag 20 via the communication cable 32. The sensor 30 includes a power feeding cable 33 and a power feeding cable 34, and power is fed through the power feeding cable 33 and the power feeding cable 34. The sensor 40 has the same configuration as the sensor 30 and operates in the same manner.

  The RFID tag 10 includes an antenna 11, a communication unit 12, a control unit 13, and a power storage unit 14. The control unit 13 acquires sensing data from the sensor 30 and the sensor 40 and outputs the sensing data to the communication unit 12. Here, the control unit 13 may AD-convert the acquired sensing data and output it to the communication unit 12. When sensing data is input from the control unit 13, the communication unit 12 performs modulation processing and drives the antenna 11. The antenna 11 transmits electromagnetic waves to the antenna 4 of the reader / writer 1 in accordance with driving from the communication unit 12. The antenna 11 receives an electromagnetic wave from the antenna 4 of the reader / writer 1 and outputs a signal corresponding to the received electromagnetic wave to the power storage unit 14.

  The power storage unit 14 generates an electromotive force using a signal corresponding to the received electromagnetic wave and stores the electromotive force. The power storage unit 14 supplies the stored power to the sensor 30, the sensor 40, the control unit 13, and the communication unit 12. Even if the signal input from the antenna 11 is interrupted, the power storage unit 14 continues to supply power if the stored power remains. The RFID tag 20 has the same configuration as the RFID tag 10 and operates in the same manner.

  The control unit 13 may receive the notification request transmitted from the reader / writer 1 via the antenna 11 and the communication unit 12 and output sensing data from each sensor in response to the notification request. The control unit 23 is the same. The sensor 30 may include a control unit (not shown) that controls the sensor 30 and output sensing data in response to a notification request from the control unit 13 or the control unit 23. The sensor 40 is the same. Sensor 30 and sensor 40 may each have a built-in power storage unit. In addition, each power supply cable and each communication cable may be shared by performing exclusive control of cable use, for example, by dividing the use time, or by performing so-called power line communication using the power supply cable as a communication cable. Good.

  FIG. 2 is an operation sequence diagram of the sensing system in the first embodiment of the present invention. Here, since the sensor 40 operates in the same manner as the sensor 30, the description of the operation sequence of the sensor 40 is omitted. Since the RFID tag 20 operates in the same manner as the RFID tag 10, the description of the operation sequence of the RFID tag 20 is omitted.

  The control unit 3 of the reader / writer 1 instructs the communication unit 2 to drive the antenna 4 (step S1). The communication unit 2 performs modulation processing according to an instruction from the control unit 3 and drives the antenna 4 (step S2). The antenna 4 transmits electromagnetic waves to the antenna 11 of the RFID tag 10 and the antenna 21 of the RFID tag 20 in accordance with the drive from the communication unit 2 (step S3). The antenna 11 of the RFID tag 10 receives an electromagnetic wave from the antenna 4 of the reader / writer 1 and outputs a signal corresponding to the received electromagnetic wave to the power storage unit 14 (step S4). The power storage unit 14 generates an electromotive force using a signal corresponding to the received electromagnetic wave, stores the power, and supplies power to the sensor 30. Similarly, the power storage unit 14 supplies power to the communication unit 12 and the control unit 13 (step S5).

  The sensor 30 outputs the sensing data to the control unit 13 of the RFID tag 10 (step S6). The control part 13 acquires sensing data from the sensor 30 and the sensor 40, and outputs them to the communication part 12 (step S7). The communication unit 12 performs modulation processing and drives the antenna 11 (step S8). The antenna 11 transmits an electromagnetic wave to the antenna 4 of the reader / writer 1 in accordance with the drive from the communication unit 12 (step S9). The antenna 4 receives electromagnetic waves from the antenna 11 of the RFID tag 10 and the antenna 21 of the RFID tag 20, and outputs a signal corresponding to the received electromagnetic waves to the communication unit 2 (step S10). The control unit 3 receives the communication data from the communication unit 2 and acquires sensing data included in the communication data (step S11). The above operation sequence may be repeated at a predetermined cycle.

  As described above, according to the embodiment of the present invention, one or more passive RFID tags are arranged at a distance where the electromagnetic wave from the reader / writer 1 reaches with sufficient intensity, and the passive RFID tag, the communication cable, and the power supply cable are connected. In addition, since sensing is performed using one or more sensors installed at remote locations, stable wireless communication can be ensured by bringing the reader / writer 1 and the passive RFID tag closer to receive strong electromagnetic waves. Moreover, it becomes a sensing system which can sense a wide range using one or more sensors installed in a distant place. Here, if wireless communication is performed from a plurality of RFID tags, multiple communication paths are provided, so that communication with the reader / writer 1 can be performed more reliably.

  In addition, since one or more passive RFID tags feed the electromotive force generated by the electromagnetic waves transmitted from the reader / writer 1 to one or more sensors installed at remote locations via cables, the built-in power supply is used. Compared to the conventional active RFID tag, the sensing system can perform sensing for a long time.

[Second Embodiment]
A second embodiment for carrying out the present invention will be described. FIG. 3 is a block diagram of a sensing system including an RFID tag according to the second embodiment of the present invention. The sensing system includes a reader / writer 1, an RFID tag 50, an RFID tag 60, and a sensing device 70. For example, the reader / writer 1 may be disposed on the ground, the RFID tag 50 and the RFID tag 60 may be installed on the ground surface, and the sensing device 70 may be embedded in the ground. In addition, the number of each block with which the said sensing system is provided does not need to be restricted to the number shown by FIG.

  The reader / writer 1 has the same configuration as the reader / writer 1 of FIG. 1 and operates in the same manner. Sensing device 70 includes sensor control unit 71, sensor 72, and power storage unit 73. The sensor control unit 71 acquires the electromotive force data (voltage value, current value, etc.) generated in the power storage unit 54 from the control unit 53. Similarly, the sensor control unit 71 acquires the electromotive force data (voltage value, current value, etc.) generated in the power storage unit 64 from the control unit 63.

  The sensor control unit 71 compares the magnitude of the electromotive force based on the electromotive force data. Here, it is assumed that the power storage unit showing the largest electromotive force is the power storage unit 54. For this reason, the RFID tag 50 including the power storage unit 54 can be expected to perform stable communication with the reader / writer 1. The sensor control unit 71 notifies the control unit 53, the control unit 63, and the power storage unit 73 of an identifier indicating the power storage unit 54 that has shown the largest electromotive force. The sensor control unit 71 acquires the sensing data from the sensor 72 and outputs the sensing data via the communication cable 77 only to the control unit 53 that controls the power storage unit 54 that exhibits the largest electromotive force. The sensor 72 is supplied with power from the power storage unit 73 and outputs sensing data to the sensor control unit 71.

  The power storage unit 73 supplies power to the sensor 72. When the identifier indicating the power storage unit notified from the sensor control unit 71 is the power storage unit 54, the power storage unit 73 is supplied with power from the power storage unit 54, and is supplied to the power storage unit 54 after a predetermined time has elapsed. When the identifier indicating the power storage unit notified from the sensor control unit 71 is the power storage unit 64, the power storage unit 73 is supplied with power from the power storage unit 64 and supplied with power to the power storage unit 64 after a predetermined time has elapsed. Here, the predetermined time may be determined by the time required for the sensor 72 to sense, for example. Sensing device 70 may incorporate a plurality of power storage units.

  The RFID tag 50 includes an antenna 51, a communication unit 52, a control unit 53, and a power storage unit 54. The control unit 53 acquires sensing data from the sensor control unit 71 and outputs the sensing data to the communication unit 52. The control unit 53 acquires electromotive force data (voltage value, current value, etc.) generated in the power storage unit 54 and outputs the data to the sensor control unit 71 via the communication cable 77. The control unit 53 acquires an identifier indicating the power storage unit having the largest electromotive force from the sensor control unit 71 via the communication cable 77. The control unit 53 notifies the power storage unit 54 of the acquired identifier.

  The communication unit 52 performs modulation processing and drives the antenna 51 to transmit sensing data input from the control unit 53. The communication unit 52 demodulates a signal corresponding to the electromagnetic wave received by the antenna 51 and outputs the signal to the control unit 53 as predetermined communication data. The antenna 51 transmits an electromagnetic wave to the antenna 4 in response to driving from the communication unit 52. The antenna 51 receives the electromagnetic wave from the antenna 4 and outputs a signal corresponding to the received electromagnetic wave to the communication unit 52 and the power storage unit 54.

  The power storage unit 54 generates an electromotive force using a signal corresponding to the received electromagnetic wave, stores the generated electromotive force, and feeds the stored power to the control unit 53 and the communication unit 52. The power storage unit 54 is notified of an identifier indicating the power storage unit from the control unit 53. When the identifier notified from the control unit 53 is not an identifier indicating itself (power storage unit 54), the power storage unit 54 supplies power to the power storage unit 73 in order to supply power to the RFID tag 60 that communicates with the reader / writer 1. This power supply is continued while the RFID tag 60 is communicating with the reader / writer 1.

  On the other hand, when the identifier notified from the control unit 53 is an identifier indicating itself (power storage unit 54), the power storage unit 54 supplies power to the power storage unit 73 for sensing by the sensing device 70. Next, the power storage unit 54 stops power supply to the power storage unit 73 of the sensing device 70 after a predetermined time has elapsed, and power for the communication unit 52 to communicate with the reader / writer 1 is supplied from the power storage unit 73. . Note that the power storage unit 54 may continue to supply power even if the signal input from the antenna 51 is interrupted and the stored power remains. The RFID tag 50 may include a plurality of power storage units. For example, the RFID tag 50 may include a power storage unit that is divided into a power storage unit that stores electromotive force and a power storage unit that stores supplied power. The RFID tag 60 has the same configuration as the RFID tag 50 and operates in the same manner.

  The control unit 53 may receive the notification request transmitted from the communication unit 2 of the reader / writer 1 via the antenna 51 and the communication unit 52 and output sensing data in response to the notification request. The same applies to the control unit 63. The sensor control unit 71 of the sensing device 70 may output sensing data in response to a notification request from the control unit 53 of the RFID tag 50 or the control unit 63 of the RFID tag 60. Further, the power supply cable and the communication cable may be shared as described above.

  FIG. 4 is an operation sequence diagram of the sensing system according to the second embodiment of the present invention. Since steps Sa1 to Sa3, which are operations of the reader / writer 1, are the same as steps S1 to S3 in FIG. 2, steps Sa1 and Sa2 are not shown. Since the operation of the antenna 61 is the same as that of the antenna 51, it is not shown. The operation of the communication unit 62 is not shown because it is the same as that of the communication unit 52.

  The antenna 51 of the RFID tag 50 receives the electromagnetic wave from the antenna 4 of the reader / writer 1 and outputs a signal corresponding to the received electromagnetic wave to the communication unit 52 and the power storage unit 54 of the RFID tag 50 (step Sa4). The power storage unit 54 generates an electromotive force by using a signal corresponding to the received electromagnetic wave and stores the electromotive force. The power storage unit 54 supplies the stored power to the control unit 53 and the communication unit 52. The power storage unit 64 operates in the same manner (step Sa5). The communication unit 52 demodulates a signal corresponding to the electromagnetic wave received by the antenna 51 and outputs the signal to the control unit 53 as predetermined communication data. The communication unit 62 operates in the same manner (step Sa6).

  When the control unit 53 receives predetermined communication data, the control unit 53 acquires electromotive force data (voltage value, current value, etc.) generated in the power storage unit 54. The control unit 63 operates in the same manner (step Sa7). The control unit 53 of the RFID tag 50 outputs the electromotive force data (voltage value, current value, etc.) generated in the power storage unit 64 of the RFID tag 60 to the sensor control unit 71 of the sensing device 70. The control unit 63 operates in the same manner (step Sa8).

  Based on the notified electromotive force data, the sensor control unit 71 of the sensing device 70 uses the identifier indicating the power storage unit 54 that is the power storage unit indicating the largest electromotive force, the control unit 53 of the RFID tag 50, and the RFID tag. The control unit 63 of 60 and the power storage unit 73 of the sensing device 70 are notified (step Sa9). The control unit 53 of the RFID tag 50 notifies the power storage unit 54 of an identifier indicating the power storage unit 54 that is the power storage unit that exhibits the largest electromotive force. The control unit 63 of the RFID tag 60 operates in the same manner (step Sa10). The power storage unit 54 of the RFID tag 50 supplies power to the power storage unit 73 of the sensing device 70. Similarly, the power storage unit 64 of the RFID tag 60 also supplies power to the power storage unit 73 (step Sa11). The power storage unit 73 supplies power to the sensor 72 (step Sa12). The powered sensor 72 outputs sensing data to the sensor control unit 71 (step Sa13).

  When a predetermined time elapses after power supply to the sensor 72 is started, the power storage unit 73 supplies power to the power storage unit 54 to store the power. Here, the power supply from the power storage unit 64 of the RFID tag 60 to the power storage unit 73 is continued (step Sa14). The sensor control unit 71 outputs the sensing data only to the control unit 53 of the RFID tag 50 (step Sa15). The control unit 53 outputs sensing data to the communication unit 52 (step Sa16). The communication unit 52 performs modulation processing and drives the antenna 51 (step Sa17). The antenna 51 wirelessly transmits the sensing data (step Sa18). The above operation sequence may be repeated at a predetermined cycle.

  As described above, according to the embodiment of the present invention, the RFID tag having the largest electromotive force is selected from among a plurality of RFID tags, and only the selected RFID tag performs wireless communication with the reader / writer and is not selected. RFID tags that do not perform wireless communication feed their own power to RFID tags that are performing wireless communication, so power is efficiently collected by collecting power in the necessary blocks and stable communication is achieved. It becomes a sensing system that can be performed.

[Third embodiment]
A third embodiment for carrying out the present invention will be described. FIG. 5 is a block diagram of a sensing system including an RFID tag according to the third embodiment of the present invention. The sensing system includes a reader / writer 1, an RFID tag 80, an RFID tag 90, and a sensing device 110. For example, the reader / writer 1 may be disposed on the ground, the RFID tag 80 and the RFID tag 90 may be installed on the ground surface, and the sensing device 110 may be embedded in the ground. In addition, the number of each block with which the said sensing system is provided does not need to be restricted to the number shown by FIG.

  The reader / writer 1 has the same configuration as the reader / writer 1 of FIG. 1 and operates in the same manner. Sensing device 110 includes sensor control unit 111, sensor 112, and power storage unit 113. The sensor 112 is supplied with power from the power storage unit 113 and outputs sensing data to the sensor control unit 111. The sensor control unit 111 acquires sensing data from the sensor 112 and outputs the sensing data only to the control unit that has notified the sensing data output request. The power storage unit 113 is supplied with power from the power storage unit 84 or the power storage unit 94, and supplies the stored power to the sensor 112.

  The RFID tag 80 includes an antenna 81, a communication unit 82, a control unit 83, and a power storage unit 84. The control unit 83 acquires sensing data from the sensor control unit 111 and outputs the sensing data to the communication unit 82. The control unit 83 acquires electromotive force data (voltage value, current value, etc.) generated in the power storage unit 84 and outputs the data to the control unit 93 via the communication cable 85. The control unit 83 acquires electromotive force data (voltage value, current value, etc.) generated in the power storage unit 94 of the RFID tag 90 from the control unit 93 of the RFID tag 90 via the communication cable 85. That is, the control unit 83 and the control unit 93 notify each other of the electromotive force data.

  The control unit 83 compares the magnitude of the electromotive force generated in each power storage unit based on the acquired electromotive force data. The control unit 83 notifies the power storage unit 84 of an identifier indicating the power storage unit showing the largest electromotive force. When the identifier indicating the power storage unit that shows the largest electromotive force indicates the power storage unit 84 that is the control target, the control unit 83 notifies the sensor control unit 111 of a sensing data output request. Hereinafter, it is assumed that the power storage unit showing the largest electromotive force is the power storage unit 84. For this reason, it can be expected that the RFID tag 80 including the power storage unit 84 can perform stable communication with the reader / writer 1. When a plurality of RFID tags are connected and electromotive force data is communicated (broadcast) to the plurality of RFID tags, each control unit communicates after detecting whether or not a communication line is available. Communication may be performed by performing carrier sense.

  The communication unit 82 performs a modulation process, and drives the antenna 81 to transmit the sensing data input from the control unit 83. The antenna 81 transmits electromagnetic waves to the antenna 4 of the reader / writer 1 in accordance with driving from the communication unit 82. The antenna 81 receives an electromagnetic wave from the antenna 4 of the reader / writer 1 and outputs a signal corresponding to the received electromagnetic wave to the communication unit 82 and the power storage unit 84.

  The power storage unit 84 generates and stores an electromotive force using a signal corresponding to the received electromagnetic wave, and supplies the stored power to the control unit 83 and the communication unit 82. The power storage unit 84 is notified of an identifier indicating the power storage unit from the control unit 83. When the identifier notified from the control unit 83 is not an identifier indicating itself (the power storage unit 84), the power storage unit 84 supplies power to the RFID tag 90 that performs communication with the reader / writer 1 via the power supply cable 102. Power is supplied to the power storage unit 94. Furthermore, the power storage unit 84 supplies power for sensing by the sensing device 110 to the power storage unit 113 of the sensing device 110.

  On the other hand, when the identifier notified from the control unit 53 of the RFID tag 80 is an identifier indicating itself (power storage unit 84), the power storage unit 84 of the RFID tag 80 communicates with the reader / writer 1 through the communication unit 82. Is supplied from the power storage unit 94 of the RFID tag 90. Note that the power storage unit 84 may continue to supply power as long as the stored power remains even if the signal input from the antenna 81 is interrupted. The RFID tag 80 may include a plurality of power storage units. For example, the RFID tag 80 may include a power storage unit that is divided into a power storage unit that stores electromotive force and a power storage unit that stores supplied power. The RFID tag 90 has the same configuration as the RFID tag 80 and operates in the same manner.

  The control unit 83 of the RFID tag 80 may receive the notification request transmitted from the reader / writer 1 via the antenna 81 and the communication unit 82 and output sensing data in response to the notification request. The control unit 93 of the RFID tag 90 is the same. The sensor control unit 111 of the sensing device 110 may output sensing data in response to a notification request from the control unit 83 of the RFID tag 80 or the control unit 93 of the RFID tag 90. Further, the power supply cable and the communication cable may be shared as described above.

  FIG. 6 is an operation sequence diagram of the sensing system according to the third embodiment of the present invention. Steps Sb1 to Sb3, which are operations of the reader / writer 1, are the same as steps S1 to S3 in FIG. 3, so steps Sb1 and Sb2 are not shown. Since the operation of the antenna 91 is the same as that of the antenna 81, it is not shown. The operation of the communication unit 92 is not shown because it is the same as that of the communication unit 82.

  The antenna 81 of the RFID tag 80 receives the electromagnetic wave from the antenna 4 of the reader / writer 1 and outputs a signal corresponding to the received electromagnetic wave to the communication unit 82 and the power storage unit 84 of the RFID tag 80 (step Sb4). The power storage unit 84 generates an electromotive force by using a signal corresponding to the received electromagnetic wave and stores the electromotive force. The power storage unit 84 supplies the stored power to the control unit 83 and the communication unit 82. The power storage unit 94 operates in the same manner (step Sb5). The communication unit 82 demodulates a signal corresponding to the electromagnetic wave received by the antenna 81 and outputs the signal to the control unit 83 as predetermined communication data. The communication unit 92 operates similarly (step Sb6).

  When control unit 83 receives predetermined communication data, it acquires electromotive force data (voltage value, current value, etc.) generated in power storage unit 84. The control unit 93 of the RFID tag 90 operates in the same manner (step Sb7). The control unit 83 of the RFID tag 80 acquires electromotive force data (voltage value, current value, etc.) generated in the power storage unit 84 and outputs the data to the control unit 93 via the communication cable 85. The control unit 83 of the RFID tag 80 acquires electromotive force data (voltage value, current value, etc.) generated in the power storage unit 94 of the RFID tag 90 from the control unit 93 of the RFID tag 90 via the communication cable 85. (Step Sb8).

  The control unit 83 compares the magnitude of the electromotive force generated in each power storage unit based on the acquired electromotive force data. Similarly, the control unit 93 operates (step Sb9). The control unit 83 notifies the power storage unit 84 of an identifier indicating the power storage unit showing the largest electromotive force. Similarly, control unit 93 notifies power storage unit 94 (step Sb10). The control unit 83 notifies the sensor control unit 111 of the sensing device 110 of the sensing data output request because the identifier indicating the power storage unit that has shown the largest electromotive force is the control unit 84 that is the object to be controlled by the control unit 83. (Step Sb11).

  Since the identifier notified from the control unit 93 of the RFID tag 90 is not an identifier indicating itself (the power storage unit 94), the power storage unit 94 of the RFID tag 90 is connected to the power storage unit 84 of the RFID tag 80 via the power feeding cable 102. Supply power. Furthermore, the power storage unit 94 of the RFID tag 90 supplies power for sensing by the sensing device 110 to the power storage unit 113 of the sensing device 110 (step Sb12).

  The power storage unit 113 supplies power to the sensor 112 (step Sb13). The powered sensor 112 outputs the sensing data to the sensor control unit 111 (step Sa14).

  The sensor control unit 111 outputs the sensing data only to the control unit 83 of the RFID tag 80 that has notified the output request (step Sb15). The control unit 83 outputs sensing data to the communication unit 82 (step Sb16). The communication unit 82 performs modulation processing and drives the antenna 81 (step Sb17). The antenna 81 wirelessly transmits sensing data (step Sb18). The above operation sequence may be repeated at a predetermined cycle.

  As described above, according to the embodiment of the present invention, the RFID tag having the largest electromotive force is selected from among a plurality of RFID tags, and only the selected RFID tag performs wireless communication with the reader / writer and is not selected. RFID tags that do not perform wireless communication feed their own power to RFID tags that are performing wireless communication, so power is efficiently collected by collecting power in the necessary blocks and stable communication is achieved. It becomes a sensing system that can be performed. In the third embodiment, since the sensing device 110 is notified of the sensing data output request, the sensing device 110 does not need to determine the magnitude of the electromotive force.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  The sensor described in the present invention corresponds to the sensor 30, the sensor 40, the sensor 72, and the sensor 112, the information terminal corresponds to the reader / writer 1, the RFID tag includes the RFID tag 10, Corresponding to the RFID tag 20, the RFID tag 50, the RFID tag 60, the RFID tag 80, and the RFID tag 90, the power feeding cables are the power feeding cable 33, the power feeding cable 34, the power feeding cable 43, and the power feeding cable. 44, the power supply cable 74, the power supply cable 75, the power supply cable 101, the power supply cable 102, and the power supply cable 103, and the first wireless communication unit corresponds to the communication unit 2, The power storage unit corresponds to the power storage unit 14 and the power storage unit 24, and the communication cable includes the communication cable 31, the communication cable 32, the communication cable 41, and the communication cable. Corresponding to the cable 42, the communication cable 85, the communication cable 104, and the communication cable 105, the sensing data acquisition unit includes the control unit 13, the control unit 23, the control unit 53, the control unit 63, and the control unit. The second wireless communication unit corresponds to the unit 83 and the control unit 93. The second wireless communication unit includes the communication unit 12, the communication unit 22, the communication unit 52, the communication unit 62, the communication unit 82, and the communication unit 92. , Corresponding to.

  The sensing device according to the present invention corresponds to the sensing device 70 and the sensing device 110, the second power storage unit corresponds to the power storage unit 54 and the power storage unit 64, and outputs electromotive force data. The units correspond to the control unit 53, the control unit 63, the control unit 83, and the control unit 93, and the electromotive force data acquisition unit includes the sensor control unit 71, the control unit 83, the control unit 93, The sensing device control unit corresponds to the sensor control unit 71 and the sensor control unit 111, the third power storage unit corresponds to the power storage unit 73, and the sensing data output unit corresponds to the sensor control unit 71. And the sensor control unit 111.

  The fourth power storage unit corresponds to the power storage unit 84 and the power storage unit 94, and the RFID tag control unit corresponds to the control unit 53, the control unit 63, the control unit 83, and the control unit 93. The fifth power storage unit corresponds to the power storage unit 113.

  The RFID tag power storage unit corresponds to the power storage unit 54, the power storage unit 64, the power storage unit 84, and the power storage unit 94, and the sensing device power storage unit corresponds to the power storage unit 73 and the power storage unit 113.

  Also, a program for realizing the steps shown in FIGS. 2, 4, and 6 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. Thus, the execution process of the communication terminal may be performed. Here, the “computer system” may include hardware such as an OS (Operating System) and peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.

Further, the “computer-readable recording medium” refers to a volatile memory (for example, DRAM (Dynamic) in a computer system serving as a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. Random Access Memory)) that holds a program for a certain period of time is also included.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above.
Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

It is a block diagram of the sensing system provided with the RFID tag in the 1st Embodiment of this invention. It is an operation | movement sequence diagram of the sensing system in the 1st Embodiment of this invention. It is a block diagram of the sensing system provided with the RFID tag in the 2nd Embodiment of this invention. It is an operation | movement sequence diagram of the sensing system in the 2nd Embodiment of this invention. It is a block diagram of the sensing system provided with the RFID tag in the 3rd Embodiment of this invention. It is an operation | movement sequence diagram of the sensing system in the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reader / writer 2 ... Communication part 3 ... Control part 4 ... Antenna 10 ... RFID tag 11 ... Antenna 12 ... Communication part 13 ... Control part 14 ... Power storage part 20 ... RFID tag 21 ... Antenna 22 ... Communication part 23 ... Control part 24 ... electric storage unit 30 ... sensor 31 ... communication cable 32 ... communication cable 33 ... feed cable 34 ... feed cable 40 ... sensor 41 ... communication cable 42 ... communication cable 43 ... feed cable 44 ... feed cable 50 ... RFID tag 51 ... antenna 52 ... Communication unit 53 ... Control unit 54 ... Power storage unit 60 ... RFID tag 61 ... Antenna 62 ... Communication unit 63 ... Control unit 64 ... Power storage unit 70 ... Sensing device 71 ... Sensor control unit 72 ... Sensor 73 ... Power storage unit 74 ... Power feeding cable 75 ... feed cable 76 ... communication cable 77 ... through Communication cable 80 ... RFID tag 81 ... Antenna 82 ... Communication unit 83 ... Control unit 84 ... Power storage unit 85 ... Communication cable 90 ... RFID tag 91 ... Antenna 92 ... Communication unit 93 ... Control unit 94 ... Power storage unit 101 ... Power feeding cable 102 ... Feed cable 103 ... Feed cable 104 ... Communication cable 105 ... Communication cable 110 ... Sensing device 111 ... Sensor control unit 112 ... Sensor 113 ... Power storage unit

Claims (6)

A sensor, an information terminal, and an RFID tag;
The sensor is fed via a feeding cable, outputs sensing data via a communication cable,
The information terminal includes a first wireless communication unit that performs wireless communication using electromagnetic waves,
The RFID tag is
A first power storage unit that stores an electromotive force generated by an electromagnetic wave transmitted from the first wireless communication unit of the information terminal and supplies power to the sensor via the power supply cable;
A sensing data acquisition unit for acquiring the sensing data from the sensor via the communication cable;
A second wireless communication unit that performs wireless communication with the information terminal and transmits the acquired sensing data;
A sensing system comprising: An information terminal, a sensing device, and a plurality of RFID tags,
The information terminal includes a first wireless communication unit that performs wireless communication using electromagnetic waves,
The RFID tag is
A second power storage unit that stores electromotive force generated by electromagnetic waves transmitted from the first wireless communication unit of the information terminal, and that feeds power through a power supply cable;
A sensing data acquisition unit for acquiring sensing data via a communication cable;
A second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal;
An electromotive force data output unit that outputs electromotive force data generated in the second power storage unit;
With
The sensing device is connected to the plurality of RFID tags via the power supply cable and the communication cable,
A sensor that outputs the sensing data;
An electromotive force data acquisition unit that acquires the electromotive force data from the electromotive force data output unit included in the plurality of RFID tags;
A sensing device controller that compares the magnitude of the acquired electromotive force and instructs to supply power to the second power storage unit in which the maximum electromotive force is generated;
A third power storage unit that supplies power supplied from other than the second power storage unit to the second power storage unit in response to an instruction from the sensing device control unit;
A sensing data output unit that outputs the sensing data to the sensing data acquisition unit included in the RFID tag including the second power storage unit;
A sensing system comprising: An information terminal, a plurality of RFID tags, and a sensing device;
The information terminal includes a first wireless communication unit that performs wireless communication using electromagnetic waves,
The RFID tag is
Storing the electromotive force generated by the electromagnetic wave transmitted from the first wireless communication unit of the information terminal, and supplying the stored electromotive force and the power supplied via a power supply cable; A power storage unit;
A sensing data acquisition unit for acquiring sensing data via a communication cable;
A second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal;
An electromotive force data output unit for outputting electromotive force data generated in the fourth power storage unit of the self RFID tag to another RFID tag;
An electromotive force data acquisition unit that acquires data of electromotive force generated in the fourth power storage unit included in another RFID tag;
The size of the electromotive force is compared based on the acquired electromotive force data, and when the fourth power storage unit of the own RFID tag indicates the maximum electromotive force, a sensing data notification request is output, and another RFID tag An RFID tag control unit that controls the fourth power storage unit of its own RFID tag so that the fourth power storage unit supplies power to the fourth power storage unit when the fourth power storage unit exhibits a maximum electromotive force;
With
The sensing device is connected to the plurality of RFID tags via the power supply cable and the communication cable,
A sensor that outputs the sensing data;
A fifth power storage unit fed from the fourth power storage unit and supplying power to the sensor;
A sensing data output unit that outputs the sensing data in response to the sensing data notification request;
A sensing system comprising: An RFID tag power storage unit that stores an electromotive force generated by an electromagnetic wave transmitted from the first wireless communication unit of the information terminal, and supplies power via a power supply cable;
A sensing data acquisition unit for acquiring sensing data via a communication cable;
A second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal;
An electromotive force data output unit for outputting electromotive force data generated in the RFID tag power storage unit;
An RFID tag comprising: A sensor that outputs sensing data;
An electromotive force data acquisition unit for acquiring electromotive force data from a plurality of RFID tags;
A sensing device control unit that compares the magnitude of the acquired electromotive force and instructs to supply power to the RFID tag power storage unit in which the maximum electromotive force is generated,
In response to an instruction from the sensing device control unit, a sensing device power storage unit that supplies power supplied from other than the RFID tag power storage unit to the RFID tag power storage unit;
A sensing data output unit that outputs the sensing data to the RFID tag including the RFID tag power storage unit;
A sensing device comprising: An RFID tag power storage unit that stores electromotive force generated by electromagnetic waves transmitted from the first wireless communication unit of the information terminal, and that feeds the stored electromotive force and power fed via a power feeding cable ,
A sensing data acquisition unit for acquiring sensing data via a communication cable;
A second wireless communication unit that wirelessly transmits the acquired sensing data to the information terminal;
An electromotive force data output unit for outputting electromotive force data generated in the RFID tag power storage unit of the own RFID tag to another RFID tag;
An electromotive force data obtaining unit for obtaining electromotive force data generated in the RFID tag power storage unit provided in another RFID tag;
The magnitude of the electromotive force is compared based on the acquired electromotive force data, and when the RFID tag power storage unit of the own RFID tag indicates the maximum electromotive force, a sensing data notification request is output, and other RFID tags An RFID tag control unit that controls the RFID tag power storage unit of its own RFID tag to supply power to the RFID tag power storage unit when the RFID tag power storage unit exhibits a maximum electromotive force;
An RFID tag comprising:

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