KR101004417B1 - Terminal Equipment for a Ward, Terminal Equipment for a Guadian and Wireless System for Preventing a Child from going missing by Using The Same - Google Patents

Abstract

The present invention relates to a wireless system for preventing a lost child, wherein a guardian wireless terminal device carried by each child performs wireless communication with a neighboring wireless terminal device to form a wireless network and to perform wireless communication. When the received field strength measured by measuring the received field strength is less than the preset threshold, a warning signal is generated to inform the surrounding that the safety distance range has been departed. In addition, a guardian's wireless terminal device possessed by a guardian performs wireless communication with a neighboring guardian's wireless terminal device to extract location information of each of the guardian's wireless terminal devices, and then calculates a distance between each of the guardian's wireless terminal devices. By displaying in the present invention, a wireless system for preventing the loss of a child is disclosed to determine whether each child leaves the safe distance area to prevent the occurrence of a child.

Anti-lost, received field strength, RF communication, position, distance

Description

Terminal equipment for a Ward, Terminal Equipment for a Guadian and Wireless System for Preventing a Child from going missing by Using The Same}

The present invention relates to a wireless system for preventing a lost child, and more particularly, to a wireless system for preventing a lost child confirming and displaying whether a terminal device for a protected person carried by a child is outside a certain stable distance area.

Recently, natural learning (experiential learning) and outdoor learning are increasing in schools, academies, or preschool. In this case, infants or lower grades of elementary school students often act out of the control of the leader, and thus, there is a lot of concern about the occurrence of a lost child.

In addition, when visiting a crowded place such as an amusement park, an amusement park, a performance hall, and the like, family members often lose their parents because of their carelessness or because their children are distracted from other parents.

Accordingly, a domestic mobile carrier provides a user with a service for tracking and confirming a location of a specific target.A method for tracking and checking a location is a handset based location, which is a tracking method using a GPS (Global Positioning System) satellite. Tracking methods are mainly used.

It has a mobile communication terminal equipped with a GPS module for each guardian and one young child, and records information on the route or time zone of the child's main route in the communication server, so that the child does not exist in the time zone. Provide information about the departure to the police or parents. At this time, the parent can search the location of the terminal of the child to find the child.

This location tracking service is in the spotlight by parents with young children or owners of dogs, especially parents with young children can use the services provided by mobile carriers to determine the location of the child to prepare for various accidents. It becomes possible.

However, when using a mobile communication terminal equipped with a conventional GPS module has a disadvantage in that the location tracking in real time is excessively charged battery consumption and communication costs.

In addition, when the number of users using the base station around the mobile communication terminal increases, there is a disadvantage that the location tracking using the mobile communication terminal is impossible because the communication system is down.

In addition, a mobile communication terminal having a GPS module is limited to an individual because of its high price, and has a disadvantage in that the cost is too large for use in an institution with a large number of personnel to manage such as a school or an institute.

An object of the present invention is to provide a wireless system for the prevention of the lost child to prevent the occurrence of the missing child in the amusement park, parks, amusement parks or various experience learning places.

Another object of the present invention is to provide a wireless system for preventing the loss of a child without implementing a global positioning system (GPS) or a separate mobile communication service.

It is still another object of the present invention to provide a wireless system for preventing a child from losing children's location by displaying location information of a mobile terminal device for a child on a web page.

In accordance with another aspect of the present invention, there is provided a terminal device for a protected person according to an embodiment of the present invention, which is an RF communication module for performing wireless communication with neighboring terminal devices for a neighbor, and the wireless communication. A reception field strength measurement unit for measuring a received electric field strength (RSSI) of a neighboring terminal device for a neighbor, and a memory for storing a data packet transmitted by the neighboring terminal device for a neighbor, and the measured reception field strength; A data packet generator for generating a data packet for transmission using the data packet and the measured reception electric field strength; and controlling each of the components, and transmitting the data packet for transmission to another nearby to-be-protected terminal device. It includes a control unit for controlling the RF communication module to.

Here, when the measured received electric field strength is less than a predetermined threshold value, it further comprises a warning unit for generating a warning sound.

The data packet transmitted by the protected terminal device performing the wireless communication accumulates location related information of another nearby protected terminal device that has performed wireless communication up to the nearby protected terminal device. The related information may include a parent ID, a group ID, and a received electric field strength.

In addition, the RF communication module is characterized in that the short-range wireless communication means selected from Bluetooth (Blue Tooth), a wireless local area network (WLAN), ultra wide band (UWB), Home RF, Zigbee.

On the other hand, the preferred embodiment of the terminal device for the guardian of the present invention, in the wireless system for preventing the loss, RF communication module for performing a wireless communication with the neighboring terminal devices for the guardian, and the neighbors to be protected by the wireless communication A distance calculator configured to calculate a distance from the terminal devices, a memory for storing the data packet and the calculated distance value transmitted by the neighboring terminal device, and a distance between the neighboring terminal devices. And a control unit for controlling each of the components, and the data packet transmitted by the neighboring terminal device for the neighboring person performing the wireless communication is transmitted to the neighboring terminal device for the neighboring to the protected person. Accumulated location-related information of other neighboring terminal devices for which communication has been performed is included. .

In addition, the control unit extracts the location-related information of the other neighboring terminal device devices that have performed wireless communication from the data packet stored in the memory to the neighboring terminal device device of the neighbor, the distance between each terminal device After calculating the, characterized in that to display the calculated distance through the display.

The apparatus may further include a warning unit that generates a warning sound when the calculated distance value with the neighboring terminal devices to perform the wireless communication or the calculated distance value between the respective terminal devices is more than a preset distance value. It is characterized by comprising.

In addition, the RF communication module is characterized in that the short-range wireless communication means selected from Bluetooth (Blue Tooth), a wireless local area network (WLAN), ultra wide band (UWB), Home RF, Zigbee.

On the other hand, a preferred embodiment of the wireless system for preventing the loss of the present invention is to perform a wireless communication with the neighboring terminal devices for the neighbors, the received field strength (RSSI) of the neighboring terminal devices for the neighbors to perform the wireless communication A plurality of to-be-protected terminal devices that are to be measured and generated by transmitting data packets transmitted by the neighboring to-be-protected terminal devices and the measured received electric field strength, and then transmitted to the outside; And a guardian terminal device for receiving a packet and calculating a distance from the guardian terminal device that has transmitted the transmission data packet, and displaying the calculated distance on a screen. Another nearby blood cell that has communicated wirelessly to the protected terminal device that sent the credit data packet. The location-related information of the guardian terminal devices is cumulatively included.

Here, the guardian terminal device extracts the location-related information from the transmission data packet, calculates a distance between each of the guardian terminal devices, and displays the calculated distance on a screen.

In this case, the location related information includes a parent ID, a group ID, and a received electric field strength.

The apparatus may further include a web server configured to display a distance between the terminal devices for the transmission of the transmission data packet or the distance between the terminal devices for the protected device on a web page. And a distance between the protected terminal devices and the distance between the protected terminal devices that have transmitted the transmission data packet to the web server through the wireless Internet.

In addition, the terminal device to be protected includes: a first RF communication module for performing wireless communication with neighboring terminal devices for a neighbor, and a received electric field strength (RSSI) of a neighboring terminal device for performing the wireless communication. By using a reception field strength measurement unit, a data packet transmitted by a neighboring terminal device for the neighboring party to perform the wireless communication, a memory for storing the measured reception field strength, and the data packet and the measured reception field strength. A data packet generation unit for generating a data packet for transmission, and a first control unit for controlling each of the components and controlling the first RF communication module to transmit the transmission data packet to the outside. do.

Here, when the measured received electric field strength is less than a predetermined threshold value, further comprises a warning unit for generating a warning sound.

The guardian terminal apparatus may further include a second RF communication module that receives a data packet for transmission from the terminal apparatuses for the guardian, a distance between the terminal equipment for the guardian who transmitted the data packet for transmission, and each of the guardians. A distance calculator for calculating a distance between the terminal devices, a memory for storing the transmission data packet and the calculated distance value, and a distance between the terminal devices for the protected terminal that transmitted the transmission data packet and the respective angles. And a second control unit for controlling each of the above components, and a display unit for displaying the distance between the terminal devices for the protected object on the screen.

The apparatus may further include a warning unit configured to generate a warning sound when the distance value between the terminal devices for the transmission of the transmission data packet or the distance value between the terminal devices for the protected device exceeds a preset distance value. .

According to an embodiment of the present invention, children can be prevented from losing a certain distance away from a certain stable distance in an experiential learning or outdoor learning with a lot of children or various amusement parks and parks, and separate GPS system or mobile communication service Since it is not used, the system can be built at a low cost.

Hereinafter, a wireless system for preventing the loss of the present invention will be described in detail with reference to FIGS. 1 to 7.

In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

1 is a view schematically showing a wireless system for preventing the loss of the present invention.

Referring to FIG. 1, children each carry a terminal device for a protected person, and perform wireless communication with each other. That is, a terminal device for a child held by a child carries out short-range wireless communication with another terminal device for a protected person within a predetermined distance, where each terminal device for a protected device receives a received signal strength (RSSI) of the other party performing wireless communication. Measure

Here, when the measured received electric field strength is less than the predetermined threshold value, the terminal device for the guardian generates a warning signal to warn the guardian or people around the safety distance area of departure.

In addition, each terminal device for the guardian performs wireless communication with a guardian terminal device possessed by a guardian (for example, a teacher or a parent). In this case, location information between the guardian terminal device is transmitted to the guardian terminal device. In this case, location information of each terminal device to be protected is accumulated and displayed on the guardian terminal device.

Here, the location information of the terminal device for the guardian may be transmitted to the terminal device for the guardian through various paths. That is, the terminal device for the to-be-protected terminal device at a distance where the wireless terminal can not directly communicate with the guardian terminal device transmits its location information through the terminal device for the to-be-guarded terminal located at a distance capable of wireless communication with the guardian terminal device directly.

According to an embodiment of the present invention, in the learning experience or outdoor learning with a lot of children, children can be prevented from occurring a certain distance away from a certain safety distance, and since the system does not use a GPS system to build a system at low cost It becomes possible.

2 is a block diagram showing the configuration of a terminal device for a ward of the present invention.

Referring to FIG. 2, the terminal device 100 for the ward of protection of the present invention is an RF communication module 110, a reception electric field strength measuring unit 120, a memory 130, a data packet generating unit 140, and an alarm unit 150. ), The power supply unit 160, and the control unit 170.

The RF communication module 110 is a short-range wireless communication means, any one short-range wireless communication means selected from Bluetooth (Bluetooth), wireless local area network (WLAN), ultra wide band (UWB), Home RF, Zigbee use.

The RF communication module 110 performs short-range wireless communication with the terminal device for the child held by each child. At this time, the RF communication module 110 transmits its ID, group ID, and the like to the other party's protected terminal device, and if there is a previously communicated terminal device for the protected party, the ID and reception of the previously communicated terminal device. The data packet including the electric field strength is transmitted.

In this case, when the power source is turned on, each of the child-bearing terminal devices maintains a wireless network connection with the protected terminal device that generates a predetermined signal and sends a response signal (ACK) thereto.

The receiving field strength measuring unit 120 measures a receiver signal strength indicator (RSSI) of a short range wireless communication channel. At this time, the reception field strength measurement unit 120 generates a predetermined signal to the controller 160 when the reception field strength of the short range wireless communication channel is less than a preset threshold.

The memory 130 stores the data packet transmitted from the opposite terminal device for the short-range wireless communication and the received field strength value measured by the receiving field strength measuring unit 120.

The data packet generation unit 140 generates a data packet for transmission using data included in the data packet transmitted from the opposite party's terminal device and the measured received electric field strength value.

The warning unit 150 generates a warning sound under the control of the controller 160 when the received electric field strength is less than a preset threshold.

 The power supply unit 160 supplies power to each component, and the power supply unit 156 preferably uses a small battery such as a cadmium battery.

The controller 170 controls each of the components. First, the controller 170 controls the RF communication module 110 to perform short-range wireless communication with a neighboring terminal device located nearby, and at this time, a signal transmitted from the other terminal device for the protected party. The reception field strength measurement unit 120 is controlled to measure the reception field strength of the receiver.

The controller 170 generates the data packet generator 140 to generate a data packet for transmission using data included in the data packet transmitted from the opposite party's terminal device and the measured reception field strength value. The control unit controls the RF communication module 110 to transmit the generated data packet to another to-be-protected terminal device connected to a wireless network.

In addition, the controller 170 controls the warning unit 150 to generate an alarm when the received electric field strength measured by the receiving electric field strength measuring unit 120 is less than a preset threshold.

The protected terminal device 100 of the present invention may be implemented in a form that can be attached to the wrist as shown in Figure 3, it may be implemented in the form of a name tag as shown in FIG. Here, the protected terminal device 100 of the present invention is not limited to this embodiment, it is convenient for the user to carry, it can be implemented in various forms in a form that is not lost.

FIG. 5 is a diagram illustrating a data packet structure transmitted between a terminal device for aee according to the present invention.

Referring to FIG. 5, a data packet transmitted between a terminal device for a guardian has a total size of 100 bytes. The data packet includes a destination ID, a source ID, a group ID, a command, the number of connection modules, a data field, and a cyclic redundancy. Checking).

Here, the destination ID indicates a destination address of the data packet, the source ID indicates a source address of the data packet, and the group ID indicates a group name to which the corresponding terminal device for the protected party belongs. For example, each child is given a group ID for each teacher (or guardian), and the group ID makes it possible to distinguish the teacher of the child.

The data field includes location related information of the terminal devices to be protected that have been passed through to the corresponding terminal device. Since the length of the data field is 90 bytes and the size of the location-related information of each UE device is 6 bytes, the data field may include the position-related information of 15 UE devices in total.

The location related information of the terminal device to be protected includes parent ID, group ID, received electric field strength, and other additional information.

6 is a view showing the configuration of a terminal device for a guardian of the present invention.

Referring to FIG. 6, the guardian terminal device 200 of the present invention may include an RF communication module 210, a distance calculator 220, a memory 230, a display 240, a warning unit 250, and a controller 260. )

The RF communication module 210 performs short-range wireless communication with a terminal device for a protected person possessed by a nearby child. At this time, the RF communication module 210 uses any one short-range wireless communication means selected from Bluetooth (Blue Tooth), wireless local area network (WLAN), ultra wide band (UWB), home RF, Zigbee.

In this case, the data packet received by the RF communication module 210 includes information about the location of the terminal device to be protected and the terminal device for the short-range wireless communication with the guardian terminal device 200 and the protected terminal device.

The distance calculating unit 220 measures the received electric field strength of a signal received from the terminal device for the guardian, which performs short-range wireless communication with the guardian terminal device 200, and then uses the distance calculation unit 220 to determine the distance from the terminal device for the guardian. Calculate

At this time, when the measured received electric field strength is less than a predetermined threshold value, the distance calculator 220 generates a predetermined signal to the controller 260.

The distance calculator 220 receives the received electric field strength among the location-related information of the terminal devices to be protected from the data packet received from the terminal device for short-range wireless communication to the terminal device. After extracting the data, the distance between each terminal device for the protected person is calculated.

The memory 230 stores a data packet received by the RF communication module 210, stores a distance value calculated by the distance calculator 220, and stores personal information of children for each group.

The display unit 240 displays distance information of children for each group by using data packets and distance data stored in the memory 230. The display unit 240 may display the location information of the children in a graphic form or in a list form.

In this case, when the guardian of the other group is displayed on the display unit 240, the guardian transmits the distance information of the child to the guardian of the group.

The guardian may determine the location of the children through the distance information displayed on the display unit 240, and may give attention to the children located at the boundary of the safe distance area so as not to leave the safe distance area.

The warning unit 250 generates a warning sound under the control of the controller 260 when the received electric field strength measured by the distance calculator 220 is less than a preset threshold.

When the distance calculated by the distance calculator 220 exceeds a preset distance, the warning unit 250 generates a warning sound under the control of the controller 260.

Here, the guardian can hear the warning sound and confirm that the predetermined child is out of the safe distance area, thereby taking necessary measures immediately to prevent the occurrence of the missing child.

In this case, the guardian may track the location and the moving direction of the child by identifying the guardian terminal device possessed by the child and the guardian terminal device last connected to the wireless network through the display unit 240.

The controller 260 controls each component. First, the control unit 260 controls the RF communication module 210 to perform short-range wireless communication with a neighboring terminal device for a neighbor. The distance calculator 220 is controlled to calculate the distance by measuring the received electric field strength.

Here, when the measured received electric field strength is less than a preset threshold, the controller 260 controls the warning unit 250 to generate a warning sound.

The controller 260 extracts the received field strength data from the module information of the terminal device to be protected from the data packet received from the other terminal device to the other terminal. The distance calculating unit 220 is controlled to calculate a distance between the terminal devices for the protected person.

Here, when the distance value calculated by the distance calculator 220 exceeds a predetermined distance value, the controller 260 controls the warning unit 250 to generate a warning sound.

In addition, the controller 260 displays the distance information of the children for each group by using the data packet received through the RF communication module 210 and the distance data calculated by the distance calculator 220. ).

On the other hand, the guardian terminal device 200 may transmit the distance information of the children of each group to a web server (not shown) through the wireless Internet to be displayed on a web page, in which case the parent of the child is remotely Information related to the location can be checked.

In this case, the web server (not shown) may store the distance information of the children of each group transmitted from the guardian terminal device 200 in a database server (not shown), to display the location of the child in real time. .

7 is a graph illustrating a method of measuring a distance by using a received electric field strength (RSSI) of a wireless signal.

The guardian terminal device 200 extracts a received field strength (RSSI) value from a data packet received through the RF communication module 210, and then reads a distance corresponding to the received field strength value. For example, referring to FIG. 7, when the received field strength value is -65 dBm, the corresponding distance is 7.5 m.

8 is a graphic diagram showing position information of a child in a guardian terminal device of the present invention.

Referring to FIG. 8, the guardian terminal device analyzes the data packet received from the guardian terminal device, calculates the distance between the children, and displays the distance information of the children on the screen.

According to an embodiment of the present invention, although the absolute position coordinates of each child are not known, the relative position of each child may be displayed, and thus, even if there is a child disconnected from the wireless network, the approximate position of the child may be estimated. It becomes possible.

9 is a view showing the position information of the child in the form of a list in the terminal device for a guardian of the present invention.

Referring to FIG. 9, each child (or student) is distinguished and displayed for each teacher through a group ID in the guardian terminal device. The guardian terminal device analyzes the data packet received from the guardian terminal device and compares the data packet with personal information of each child stored in the memory to display whether each child is normally located within the safe distance area.

In this case, when each teacher displays location information of a child who does not belong to his group, the teacher may transmit the location information of the child to the guardian terminal device of the corresponding teacher.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. Will understand.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

1 is a schematic view of a wireless system for preventing the lost of the present invention.

2 is a block diagram showing the configuration of a terminal device for a ward of the present invention.

3 is a diagram showing a first embodiment of a terminal device for a ward of the present invention.

4 is a diagram showing a second embodiment of a terminal device for a ward of the present invention.

5 is a diagram illustrating a data packet structure transmitted between a terminal device for aee of the present invention.

6 is a diagram showing the configuration of a terminal device for a guardian of the present invention.

7 is a graph illustrating a method of measuring distance using received field strength (RSSI) of a wireless signal.

8 is a view showing the position information of the child in the graphic form in the guardian terminal device of the present invention.

9 is a view showing the position information of the child in the form of a list in the terminal device for a guardian of the present invention.

Explanation of symbols on the main parts of the drawings

100: terminal device for the protectee 110: RF communication module

120: reception field strength measurement unit 130: memory

140: data packet generation unit 150: warning unit

160: power supply unit 170: control unit

200: protector terminal device 210: RF communication module

220: distance calculation unit 230: memory

240: display unit 250: warning unit

260 control unit

Claims (17)

In the wireless system for preventing the loss of An RF communication module for performing wireless communication with neighboring to-be-protected terminal devices; A reception field strength measurement unit for measuring a reception field strength (RSSI) of a neighboring terminal device for the wirelessly guarded device; A memory for storing a data packet transmitted by a neighboring to-be-protected terminal device performing the wireless communication and the measured received electric field strength; A data packet generator for generating a data packet for transmission using the data packet and the measured reception electric field strength; And A control unit which controls the respective components and controls the RF communication module to transmit the transmission data packet to another neighboring to-be-protected terminal device; Including; The data packet transmitted by the neighboring terminal device for the neighbors performing the wireless communication includes the accumulation of location-related information of another neighboring terminal device for the neighbors that have been performing wireless communication up to the neighboring terminal device. A protected terminal device. The method of claim 1, And a warning unit for generating a warning sound when the measured received electric field strength is less than a predetermined threshold value. The method according to claim 1 or 2, The RF communication module may be a short-range wireless communication means selected from among Bluetooth, Wireless Local Area Network, Ultra Wide Band (UWB), Home RF, and Zigbee. delete The method of claim 1, The location-related information includes a parent ID, a group ID, and a received electric field strength. In the wireless system for preventing the loss of An RF communication module for performing wireless communication with neighboring to-be-protected terminal devices; A distance calculator which calculates a distance from neighboring to-be-protected terminal devices performing the wireless communication; A memory for storing a data packet transmitted by the neighboring UEs and the calculated distance value; A display unit configured to display a distance from the neighboring terminal devices to the neighbor on the screen; And It includes a control unit for controlling each component, The data packet transmitted by the neighboring terminal device for the neighbors performing the wireless communication accumulates location-related information of another neighboring terminal device for the neighboring devices that have been performing wireless communication up to the neighboring terminal device for the neighboring. Guardian terminal device characterized in that. The method of claim 6, The control unit calculates the distance between each of the terminal devices to be protected by extracting the location-related information of another nearby terminal device for the wireless communication from the data packet stored in the memory to the nearby terminal device And then displaying the calculated distance through a display unit. The method of claim 7, wherein And a warning unit for generating a beep sound when the calculated distance value with neighboring to-be-protected terminal devices performing the wireless communication or the calculated distance value between each of the to-be-protected terminal devices exceeds a preset distance value. Guardian terminal device, characterized in that made. The method of claim 6, The RF communication module is a terminal device for a guardian, characterized in that any one of the short-range wireless communication means selected from Bluetooth (Blue Tooth), Wireless Local Area Network (WLAN), Ultra Wide Band (UWB), Home RF, Zigbee. Performing wireless communication with neighboring to-be-guaranteed terminal devices, measuring received field strength (RSSI) of neighboring to-be-guaranteed terminal devices, and transmitting by neighboring to-be-guaranteed terminal devices A plurality of protected terminal devices for generating a data packet for transmission using the data packet and the measured received electric field strength and transmitting the data packet to the outside; And And a guardian terminal device that receives the transmission data packet, calculates a distance to the guardian terminal device that has transmitted the transmission data packet, and displays the calculated distance on a screen. The transmission data packet includes accumulating the position-related information of another nearby protected terminal device that has performed wireless communication up to the protected terminal device that transmitted the transmitting data packet. Wireless system for. The method of claim 10, The terminal device for the guardian, And extracting the location-related information from the data packet for transmission to calculate the distance between each terminal device for the protected party, and then displaying the calculated distance on the screen. The method of claim 11, It further comprises a web server for displaying on the web page the distance between the protected terminal devices or the distance between the protected terminal devices for transmitting the transmission data packet, The guardian terminal device transmits the distance to the web server to the web server through the wireless Internet, the distance between the terminal device for the transmission and the distance between each of the terminal devices to be transmitted to the web server. For wireless systems. The method of claim 11, The location related information includes a parent ID, a group ID, and a received electric field strength. The method of claim 10, The protected terminal device, A first RF communication module for performing wireless communication with neighboring to-be-protected terminal devices; A reception field strength measurement unit for measuring a reception field strength (RSSI) of a neighboring terminal device for the wirelessly guarded device; A memory for storing a data packet transmitted by the neighboring terminal device for the ward and the measured received electric field strength; A data packet generator for generating a data packet for transmission using the data packet and the measured reception electric field strength; And And a first control unit controlling the respective components and controlling the first RF communication module to transmit the transmission data packet to the outside. The method of claim 14, And a warning unit for generating a warning sound when the measured received electric field strength is less than a predetermined threshold value. The method of claim 11, The terminal device for the guardian, A second RF communication module for receiving a data packet for transmission from the neighboring terminal devices for the ward; A distance calculator configured to calculate a distance from the terminal devices to which the transmission data packet has been transmitted and a distance between the terminal devices to be protected; A memory for storing the transmission data packet and the calculated distance value; A display unit configured to display a distance between the protected terminal devices and the distance between the protected terminal devices that have transmitted the transmission data packet on a screen; And And a second control unit for controlling each of the components. The method of claim 16, And a warning unit generating a warning sound when the distance value between the terminal devices for the transmission of the transmission data packet or the distance value between the terminal devices for the protected device exceeds a preset distance value. Wireless system for prevention of lost child.

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