JP4881699B2 - Wireless node device - Google Patents

Description

  The present invention relates to a wireless node device, and more particularly to a wireless node device suitable for a sensor network node that transmits information detected by a sensor to another device via a wireless base station.

A sensor network in which a plurality of wireless node devices (hereinafter referred to as sensor nodes) each having a sensor unit communicate with a monitoring center connected to a wireless LAN via a wireless base station cannot be monitored by humans. It is effective as a monitoring system at a place.
In the sensor node, for example, a sensor unit according to the monitoring purpose such as a monitoring camera, a temperature sensor, and a harmful gas sensor is mounted. Each sensor node is arranged within a range where it can communicate with one of a plurality of base stations constituting the wireless LAN, and reports peripheral state information detected by the sensor unit to the monitoring center via the wireless base station and wireless LAN. To do. The monitoring result is reported either periodically or autonomously when an abnormal state is detected, or in response to a command from the monitoring center.

  The sensor nodes constituting the sensor network are installed at positions away from the monitoring center, and normally operate in a place that is not easily noticeable. Therefore, for example, in a security monitoring system, damage such as destruction of a sensor node by an unauthorized intruder into the monitoring area or a change in the installation state of the sensor node for shifting the monitoring range occurs. As standardization of device specifications of sensor nodes progresses and versatility increases, there is an increased risk that a sensor node stolen from an operating monitoring system will be resold and reused in another monitoring system. For such crimes, sensor information authentication and conventional information security techniques represented by encrypted communication are ineffective, and new countermeasure techniques are required.

  As anti-theft technology for goods, security gates used in retail trade, anti-theft tags, and the like are known. The anti-theft tag is attached to the product by a strong cable member such as a wire, and when the product is illegally taken out from where it should be, it has a function to detect the disconnection of the tag mooring cable and issue an alarm. Yes.

  Japanese Patent Application Laid-Open No. 11-24570 (Patent Document 1) proposes a special seal that prevents unauthorized replacement of parts such as a ROM storing a game program. This seal seal has a wiring pattern formed of a resistor or a conductor on the surface, and both ends of the wiring pattern are connected to a sensor. If the seal is broken illegally, the wiring pattern is damaged. Therefore, the opening of the seal can be electrically detected by monitoring the conductive state between the terminals of the wiring pattern with a sensor.

  Japanese Patent Application Laid-Open No. 2004-139285 (Patent Document 2) proposes an antitheft device comprising an adhesive label attached to a product, a label holder, and a controller connected to the label holder. The pressure-sensitive adhesive label is formed with a label breakage portion that promotes breakage of the wiring pattern formed on the label surface. Further, both ends of the wiring pattern are coupled to two lead wires by a label holder, and a change in the conductive state between the lead wires is monitored by a controller. When someone tries to peel off the adhesive label from the product, the wiring pattern is broken by the broken part of the label, and the lead wire is disconnected, so the controller detects the unauthorized removal of the adhesive label and the buzzer is turned off. Can be ringed.

Japanese Patent Laid-Open No. 11-024570 JP 2004-139285 A

  In sensor networks used for wide-area environmental sensing and public infrastructure monitoring, the administrator is often located away from the monitoring zone, and even if an alarm is issued from the sensor node, the administrator can quickly reach the site. It is difficult to arrive. For this reason, it is difficult to prevent the sensor node from being stolen and to prevent an unauthorized intruder from escaping.

  As a technique for preventing unauthorized use of information equipment, there is a method of requesting a user to input a password when using the equipment, and collating it with a pre-registered password. According to the password method, since a person who does not know a valid password cannot use the device, unauthorized use of the device can be prevented.

However, an information device incorporated in a system such as a sensor node does not include a password input unit such as a keyboard, unlike a single PC or a mobile phone owned by a user. In many cases, the sensor network is managed by a company, and the node device is maintained by an unspecified worker. For this reason, in order to restart a node device that has once stopped operation using the password method when the maintenance work is completed, each worker needs to carry some kind of medium that records the startup password, and there is a problem with password management. is there.
In addition, in order to prevent the sensor node from being stolen and illegal movement, it is necessary to firmly fix each node device at the installation location, which makes it difficult to replace parts and devices in maintenance work, Increase in maintenance costs.

  An object of the present invention is to prevent unauthorized use of a wireless node device that has been stolen and diversion to another system.

In order to achieve the above object, the wireless node device of the present invention provides:
An interface for reading a passcode from a code information holding medium fixed outside the apparatus; an internal memory for storing a startup passcode; and a program memory storing at least a startup routine and a passcode check routine;
During the period when the wireless node device is in an operating state, the passcode check routine is periodically executed to collate the passcode read from the code information holding medium with the activation password stored in the internal memory, When a password mismatch is detected, an alarm message is transmitted to the other device, and when the wireless node device is restarted, the activation routine is executed, and the passcode read from the code information holding medium is stored in the internal memory. It is characterized by comprising a processor that stops execution of the startup routine when a password mismatch is detected by collating with the startup password, and is operated with an appropriate code information holding medium.

  The wireless node device of the present invention functions as a sensor network node device by including a sensor unit. More specifically, in the wireless node device of the present invention, when the processor first executes the activation routine, the passcode read from the code information holding medium is stored as an activation password in the internal memory. Further, the code information holding medium and the interface are coupled by wire or wirelessly.

  In one embodiment of the present invention, the code information holding medium and the interface are coupled by a plurality of pairs of input and output lines corresponding to the bit positions of the passcode, and the code information holding medium is connected to the input and output on the surface. A wiring pattern connected to the line, and a pass code is represented by a combination of connection / disconnection states of each wiring pattern, and the interface determines the connection / disconnection state of the input / output lines, and the code The passcode is read from the information holding medium.

  The wireless node device according to the present invention has one activation condition that an appropriate code information holding medium is attached, and a passcode that matches the activation passcode stored in the internal memory from the code information holding medium at the time of restart. If it cannot be read, execution of the startup routine is stopped. Therefore, even if the wireless node device encounters theft, if the code information holding medium is lost or damaged, the wireless node device cannot be operated, and thus has a deterrent against theft.

  Further, since the wireless node device of the present invention reads the passcode from the code information holding medium fixed outside the device, when the wireless node device is inadvertently moved or removed from the installation position, the code By keeping the information holding medium in the field or being pulled by the connection line so as to be damaged, it is possible to detect an abnormality of the wireless node device and transmit an alarm message.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 2 shows a configuration example of a sensor network to which the sensor node of the present invention is applied.
The sensor network includes a plurality of sensor nodes SN (1A, 1B, 1C, 1D, 1E,...) Each having a sensor unit, and a plurality of radio base stations 2 (2A, 2B,...) Connected to the LAN 4. And) and the monitoring center 3. Each sensor node SN is arranged at a position where it can wirelessly communicate with any one of the radio base stations 2, and transmits surrounding monitoring information detected by the sensor unit to the monitoring center 3 via the radio base station 2. The monitoring center 3 is configured by a control device having a display function corresponding to the function of the sensor unit.

FIG. 1 shows an embodiment of a sensor node SN according to the invention.
The sensor node SN includes a main control board 10, a radio communication antenna 20, a sensor unit 21, a display unit 22, a power source 23, a power switch 24, and a reset switch 25. The type of the power source 23 is not particularly limited, but a battery that can be used up such as a button battery or a dry battery, a rechargeable battery such as a lithium ion battery, or a power generation device that includes a solar battery, a signal power generation element, etc. .

  The main control board 10 is connected to a processor 11, a ROM 12 storing various programs and control data, an EEPROM 13 and a RAM 14 that can rewrite data, an RF circuit 15 connected to an antenna 20, and a display unit 22. The display control circuit 16 and the passcode interface 17 are connected to each other by the internal bus 18.

  The ROM 12 includes, as software related to the present invention, a startup routine 100 described later with reference to FIG. 4, a main program 200 for realizing the functional operation of the sensor node SN, and a passcode periodic check program 300 described later with reference to FIG. Stored. The EEPROM 13 stores control information such as a node ID and a MAC address, and an activation passcode 130 referred to by the activation routine 100 and the passcode periodic check program 300.

  A feature of the present invention is that a code information holding medium 5 is prepared in association with each sensor node SN. The code information holding medium 5 stores a security passcode that is a unique passcode for each sensor node. In this embodiment, the code information holding medium 5 is connected to the passcode interface 17 via the connection line L, and the security passcode stored in the code information holding medium 5 is read out by the passcode interface 17.

  The activation routine 100 executed when the reset SW 25 is pressed and the passcode periodic check program 300 executed at a predetermined cycle are the security passcode read from the code information holding medium 5 and the activation stored in the EEPROM 13. The pass code 130 is collated to determine the correspondence between the sensor node SN and the code information holding medium 5. When the activation routine 100 is executed for the first time, the security passcode read from the code information holding medium 5 is registered in the EEPROM 13 as the activation passcode 130. Once the activation passcode 130 is registered in the EEPROM 13, the security passcode cannot be normally read from the code information holding medium 5, or when a mismatch between the security passcode and the activation passcode 130 is detected. The sensor node protection function such as the start / stop of the sensor node SN or the transmission of an alarm message to the monitoring center works.

FIG. 3 shows an embodiment of the code information holding medium 5 and the passcode interface 17.
The code information holding medium 5 of the present embodiment has a plurality of input / output terminals TI-j and TO-j (j = 1 to n) on the surface of the sheet, and the wiring Cj ( j = 1 to n). The connection sheet is in a disconnected (OFF) state by stripping off a part of the specific wiring, for example, as indicated by the wirings C1 and C3 marked with x. For example, when a wire in a conductive state (ON) is associated with bit “1” and a wire in a disconnected state (OFF) is associated with bit “0”, the security of n bits is determined by the combination of the wiring on the connection sheet. Can represent a passcode.

  In this embodiment, the passcode interface 17 includes a plurality of sets of input / output terminals PI-j, PO-j (j = 1 to n), a read control circuit 170, a selector 172, and a read control circuit 170. And a connected register 173.

  The input / output terminals PI-j and PO-j are connected to the input / output terminals TI-j and TO-j (j = 1 to n) on the code information holding medium (connection sheet) 5 by the connection line Lj. ing. In this embodiment, the voltage V divided by the resistance elements R1 and R2 is applied to each output terminal PO-j, and the potential of each input terminal PI-j is detected by the read control circuit via the selector 172. It can be done.

  When the read control circuit 170 receives a security passcode read command from the processor 11 via the internal bus 18 (control bus 18C), the read control circuit 170 controls the selector 172 to input terminals TI-j (j = 1 to n). The potential that appears is sequentially determined. If the wiring line Cj is conductive, the output of the selector 172 has a predetermined potential indicating the bit “1”, and if the wiring line Cj is disconnected, the output of the selector 172 is a zero potential indicating the bit “0”. It becomes. The reading control circuit 170 determines the value of each bit of the security passcode indicated by the code information holding medium (connection sheet) 5 by performing binary determination on the output of the selector 172, and sequentially stores the value in the register 173.

  When the n-bit security passcode is stored in the register 173, the read control circuit 170 notifies the processor 11 of the completion of reading the security passcode via the internal bus (control bus 18C). The processor 11 reads the n-bit security passcode stored in the register 173 via the internal bus 18 (data bus 18D). However, the security passcode reading completion notification may be omitted, and the processor 11 may autonomously access the register 173 when a predetermined time has elapsed since the reading command was issued.

  FIG. 4 shows a flowchart of the startup routine 100. The activation routine 100 is executed by the processor 11 when the maintenance staff of the sensor node SN operates the power switch 24 to turn on the power source 23 and then operates the reset switch 25.

  When the startup routine 100 is executed, the processor 11 checks the state of the memories 12 to 13 (step 101), and then executes the passcode check routine 400.

  In the passcode check routine 400, as shown in FIG. 6, first, a security passcode is read from the code information holding medium 5 (401). In this embodiment, reading the security passcode (401) means that the processor 11 gives a passcode read command to the passcode interface 17 via the control bus 18C.

  The processor 11 determines from the security passcode value read from the code information holding medium 5 whether or not the security passcode has been normally read (whether there is a read error) (402). For example, when the code information holding medium 5 does not exist or when the connection line L between the passcode interface 17 and the code information holding medium 5 is disconnected, the value of the security passcode in the register 173 is zero. Become. If the value of the security passcode is not within the predetermined allowable range, the processor 11 determines that it is a read error, outputs a passcode error message to the display unit 22 (408), and displays the passcode check result as NG. (409), and this routine is finished.

  When the security passcode is normally read from the code information holding medium 5, the processor 11 reads the activation passcode 130 from the memory (EEPROM) 13 (403). If the activation passcode 130 is not registered, the security passcode is registered in the memory (EEPROM) 13 as the activation passcode 130 (406), the passcode check result is OK (407), and this routine is terminated. .

  When the activation passcode 130 is already registered in the memory (EEPROM) 13, the processor 11 collates the activation passcode 130 with the security passcode read from the code information holding medium 5 (405). If these two passcodes do not match, the processor 11 executes steps 408 and 409. If they match, the processor 11 executes step 407 and ends this routine.

  Returning to FIG. 4, the processor 11 determines the check result of the pass code (102), and if the pass code is OK, executes the function check of the sensor node (103). If an abnormality is found in the function as a sensor node, the processor 11 outputs an error message to the display unit 22 (105), and this routine is terminated. If there is no abnormality in the sensor node function, the processor 11 activates the main program 200. Thereby, the sensor node SN shifts to the operation state in the predetermined monitoring mode according to the main program 200. If the passcode check result is NG, the processor 11 terminates the activation routine 100 without executing the main program 200.

FIG. 5 shows a flowchart of a passcode periodic check routine 300 that is periodically executed by a timer interrupt.
In the passcode periodic check routine 300, the processor 11 determines the passcode check result after executing the passcode check routine 400 (301). If the pass code is OK, the processor 11 ends this routine. If the pass code is NG, the processor 11 transmits an alarm message including node identification information to the monitoring center 3 (302), and ends this routine. However, after transmitting the alarm message, the processor 11 may end the execution of the main program and stop the function as the sensor node.

  According to the above embodiment, when the activation routine 100 is executed and the passcode check result is NG, the processor 11 ends the activation routine 100 without executing the main program 200. That is, if the appropriate code information holding medium 5 associated in advance is not connected to the sensor node SN, the sensor node SN does not function, so even if the sensor node SN is stolen from the active monitoring system, Without the accompanying code information holding medium 5, it becomes impossible to divert the sensor node to another monitoring system.

FIG. 7 is a cross-sectional view showing an embodiment of the code information holding medium 5.
Reference numeral 50 denotes a substrate of the code information holding medium 5. A wiring pattern (C 1 to Cn in FIG. 3) 52 is formed on the front surface, and an adhesive layer 54 is formed on the back surface. 53 is a terminal (input / output terminal TI-j, TO-j) formed at the end of the wiring pattern 52, and is coupled to the connection line L to the security passcode interface 17. When the code information holding medium 5 is in an unused state, the surface of the adhesive layer 54 is covered with a protective film. When the sensor node SN is installed at the monitoring site, the protective film is peeled off, and the code information holding medium 5 is stretched on the wall surface or pillar near the sensor node.

  A notch 51 is formed on the rear surface of the substrate 50 so that the substrate is cracked and the wiring pattern 52 is disconnected when an excessive force is applied in the peeling direction of the code information holding medium 5 already installed in the field. Yes.

FIG. 8 is a plan view showing another embodiment of the code information holding medium 5.
The passcode medium 5 is stretched on the wall surface by an adhesive layer formed on the back surface. Reference numeral 6 denotes an adhesive tape that covers the main parts of the wiring patterns C1 to Cn and is stretched on the wall surface so that the security passcode is not visually read. As the adhesive tape 6, one having strong adhesiveness is applied so that the wiring patterns C <b> 1 to Cn are destroyed when the adhesive tape 6 is forcibly peeled off.

As the code information holding medium 5, a medium having the notch 51 for breaking shown in FIG. 7 can be applied. In this case, for example, even if the code information holding medium 5 is peeled off the wall surface in a state where both end portions of the adhesive tape 6 are peeled off from the wall surface, the medium substrate is broken along the notch 51 and the wiring pattern is destroyed. The reuse of the sensor node SN can be prevented. Further, when the connection lines L (IN) and L (OUT) are forcibly pulled together with the sensor node SN, the stress related to the code information holding medium 5 is concentrated on the notch 51 and the wiring pattern is destroyed. The
It should be noted that when a metal fastener is applied instead of the adhesive tape 6 and the code information holding medium 5 is to be peeled off, the wiring pattern may be damaged and the security pass code may have a different value. Good.

  As described above, when the code information holding medium 5 and the passcode interface 17 are coupled by the connection line L, for example, when someone connects the sensor node SN and the connection line L is disconnected, the passcode An abnormality can be detected by the periodic check routine 300 and an alarm message can be transmitted to the monitoring center. The same applies when someone tries to forcefully change the direction of the sensor node SN.

FIG. 9 shows another embodiment of the sensor node SN according to the present invention.
In the sensor node SN of this embodiment, an RFID (Radio Frequency Identification) device 5A incorporating a semiconductor IC is applied as the code information holding medium 5, and an antenna 26 is provided as the security passcode interface 17 shown in FIG. The RFID reader 17A is applied. In the RFID system, information can be read from the RFID device 5A located nearby by transmitting a read signal wirelessly from the RFID reader 17A.

  Therefore, if the security passcode is stored in the RFID device 5A and the RFID device 5A is installed within the range where the weak radio wave from the antenna 26 reaches, the security pass is given by giving a reading command to the RFID reader 17A. The code can be read, and the security passcode and the activation passcode can be verified by executing the passcode check routine 400 described in FIG.

  When the RFID device 5A is applied, the code information holding medium 5 can be installed at the monitoring site in a state independent of the sensor node SN. Therefore, since the RFID device 5A can be installed in an inconspicuous position, even if the sensor node SN is stolen, if the RFID device 5A paired with the sensor node SN is left in the field, the pass code check at the time of activation It becomes possible to prevent the sensor node from being reused.

  As the code information holding medium 5, a connection sheet type, other than the RFID device, for example, an IC tag type may be applied. Further, in the passcode check routine 400 shown in the embodiment, when the reset SW is operated with the activation passcode not registered, the security passcode is registered as the activation passcode (406), and then the passcode OK is changed. Although the passcode check routine is terminated in the state, when the activation passcode is registered, a reset request message is displayed on the display unit 22 to terminate the activation routine 100 and allow maintenance personnel to operate the reset SW again. Good.

  In this way, when a new sensor node SN is installed at the monitoring site, it is possible to notify maintenance personnel that the sensor node is operating normally in the initial mode. When the maintenance staff re-operates the reset SW, the match between the security passcode and the activation passcode is confirmed and the passcode is OK. Therefore, if there is no problem in the node function, the sensor node can be sure of the main program 200. You can enter run mode.

The figure which shows one Example of the sensor node by this invention. The figure which shows the structural example of the sensor network to which the sensor node of this invention is applied. The figure which shows one Example of the code information holding medium 5 and the passcode interface 17. FIG. The flowchart which shows one Example of the starting routine 100 performed with the sensor node SN of this invention. The flowchart which shows one Example of the passcode regular check routine 300 performed by the sensor node SN of this invention. The flowchart which shows one Example of the passcode check routine 400 performed by the sensor node SN of this invention. Sectional drawing which shows one Example of the connection sheet type code | cord | chord information holding medium 5. FIG. The figure which shows the other Example of the connection sheet type | mold code information holding medium 5. FIG. The figure which shows the other Example of the sensor node by this invention.

Explanation of symbols

SN: sensor node, 2: wireless base station, 3: monitoring center, 5: code information holding medium, 11: processor, 12: ROM, 12: EEPROM, 14: RAM, 15: RF circuit, 16: display control circuit, 17: Passcode interface, 21: Sensor unit, 22: Display unit, 23: Power supply, 24: Power supply SW, 25: Reset SW, 100: Startup routine, 130: Startup passcode, 200: Main program, 300: Path Code periodic check routine.

Claims (9)

A wireless node device that communicates with other devices via a wireless base station,
An interface for reading a passcode from a code information holding medium fixed outside the apparatus;
An internal memory for storing the activation passcode;
A program memory storing at least a startup routine and a passcode check routine;
During the period in which the wireless node device is in Running state, the passcode check routine periodically run, the boot path code stored in the passcode and the internal memory read from the code information storage medium when collated to detect the path code mismatch, sends an alarm message to the other device, upon restart of the wireless node device, running the boot routine, the pass code read from the code information storage medium and collating the startup path code stored in the internal memory, when detecting the pass code mismatch consists of a processor of stopping the execution of the startup routine,
The processor stores the passcode read from the code information holding medium in the internal memory as an activation passcode when the activation routine is executed when the activation passcode is not stored in the internal memory;
A wireless node device operated with an appropriate code information holding medium.   The wireless node device according to claim 1, wherein the processor stops the function of the wireless node device after transmitting the alarm message. The radio node apparatus according to claim 1, wherein the interface is coupled to the code information holding medium by a set of connection lines . The interface and the code information holding medium are coupled by a plurality of pairs of input and output lines corresponding to the bit position of the passcode,
The code information holding medium has a wiring pattern connected to the input and output lines on the surface, and represents the pass code by a combination of connection / disconnection states of the wiring patterns,
4. The wireless node device according to claim 3, wherein the interface determines a connection / disconnection state of the input / output line and reads a pass code from the code information holding medium . 5. The wireless node device according to claim 4, wherein the code information holding medium has an adhesive layer on a back surface, and is fixed in the vicinity of the wireless node device by the adhesive layer . The wireless node device according to claim 1, wherein the interface is wirelessly coupled to the code information holding medium . 2. The wireless node device according to claim 1, wherein the code information holding medium is made of a semiconductor IC storing the passcode . A sensor unit coupled to the processor;
The wireless node device according to claim 1, wherein the processor transmits monitoring information generated based on an output of the sensor unit to the other device . 9. The wireless node device according to claim 8, wherein the other device is a terminal device serving as a monitoring center of a sensor network system .

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