A reusable NFC wire tag seal and monitoring system and method thereof

Abstract

The application provides a reusable NFC steel wire seal and a monitoring system and method thereof, and belongs to the field of logistics safety and intelligent identification. The technical scheme of the application comprises: a circuit board and two lock heads of built-in funnel ball self-locking mechanisms arranged in the shell, a steel wire passing through the lock heads and a steel wire detection module to form a conductive loop; the circuit board performs a force-electric dual mode weighted discrimination algorithm, fuses real-time steel wire tension and loop current to perform state determination, and records the number of uses when the state is switched; and the state and the number of uses are sent to an external reader / writer through an NFC radio frequency circuit. The scheme realizes the recycling of the seal body, effectively identifies violent cutting, soft damage and electrical attack behavior through force-electric dual mode fusion determination, improves the characteristics of tamper-proof determination, and optimizes the NFC communication performance through double-sided PCB layout.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of logistics security and intelligent identification technology, specifically to a reusable NFC wire seal and its monitoring system and method. Background Technology

[0002] In the fields of logistics, warehousing management, and supply chain security, traditional physical seals such as lead seals and plastic seals are widely used to ensure the integrity of goods or containers. However, these traditional seals have the following significant drawbacks: First, they are usually for single use only, and are destroyed once opened, making them unusable and resulting in high costs and environmental pollution. Second, they lack status recording and contactless identification capabilities; managers must conduct close visual inspections or use specialized tools to verify their status, making it difficult to achieve automated and information-based status monitoring and data collection.

[0003] To address these issues, electronic seals have emerged in existing technologies. For example, international patent WO2016033914A1 discloses an NFC tamper-evident seal. This seal forms a conductive circuit by inserting a wire into a steel cable and connecting it to an NFC chip and antenna. When the steel cable is cut, the circuit breaks, thus achieving tamper-evident detection. However, this solution is a single-use product; the electronic components are rendered unusable after the steel cable is cut, resulting in high costs. Another example is patent CA2835280A1, which discloses a reusable bolt electronic seal. Its electronic module can be reused after the bolt is cut. However, this solution uses a bolt-pin structure, and its tamper-evident detection relies primarily on simple circuit continuity detection. This makes it susceptible to electrical attacks through parallel bypassing and other methods, rendering it ineffective. Furthermore, it lacks awareness of the physical state of the steel cable, such as its mechanical tension, and cannot recognize "soft damage" behavior where the steel cable is partially cut but the circuit remains conductive.

[0004] Therefore, existing wire sealing technology still has shortcomings in terms of recyclability, tamper-proof judgment, and multi-physical state fusion sensing. There is an urgent need for a solution that can take into account reusability, high security, and intelligent monitoring. Summary of the Invention

[0005] The purpose of this invention is to provide a reusable NFC wire seal and its monitoring system and method. By implementing this invention, the seal can be reused repeatedly, and force-electric dual-mode parameters can be integrated for tamper-proof determination.

[0006] To achieve the aforementioned objective, in a first aspect, embodiments of the present invention provide a reusable NFC wire seal, the technical solution of which is: Includes: an outer shell, formed by a top cover and a bottom shell.

[0007] The circuit board, located inside the outer casing in the circuit board compartment, includes the main control circuit, NFC radio frequency circuit, NFC antenna, and wire detection module.

[0008] Two locks are located in two independent lock compartments on the bottom shell. Each lock has a funnel-shaped self-locking mechanism for allowing the steel wire to pass through in one direction.

[0009] The steel wire detection module forms a conductive circuit by connecting the contact point with the two locks and the steel wire passing through the two locks via a wire.

[0010] The main control circuit is configured to perform the following steps: Data acquisition steps: The tension value of the steel wire is acquired in real time using the steel wire detection module. F t and the current value of the conductive circuit I t .

[0011] Calculation steps: Based on the preset weighting coefficients, combined with the standard initial tension value during the sealing timing. F std and the rated current value of the conductive circuit under normal closed state I std Calculate the comprehensive state value S(t).

[0012] Judgment and Recording Steps: Determine the current state of the wire seal based on the comprehensive state value S(t), and record the number of uses when the state changes.

[0013] Communication steps: Control the NFC radio frequency circuit to send the current status and number of uses to the external reader via the NFC antenna (15).

[0014] The main control circuit is configured to execute the following force-electric dual-mode weighted discrimination algorithm to calculate the comprehensive state value. S(t) :

[0015] in, The tension value of the steel wire is collected in real time. The standard initial tension value for signing the sealing time. The current value of the conductive circuit is collected in real time. This is the rated current value under the normal closed state of the conductive circuit. α and β These are the preset weighting coefficients.

[0016] In a preferred embodiment, the circuit board is a double-sided printed circuit board. The front side integrates the main control circuit, NFC radio frequency circuit, and wire detection module, while the back side houses the NFC antenna. An NFC scanning area is located on the outer surface of the top cover, with the NFC antenna positioned vertically opposite the NFC scanning area to create spatial isolation between the NFC antenna and the main control circuit and NFC radio frequency circuit. This configuration reduces electromagnetic interference from the main control circuit and other electronic components to the NFC antenna, improving the read / write distance and sensitivity of near-field communication.

[0017] In a preferred embodiment, the seal further includes a screw for securing the end of the wire to the lock head and creating a floating electrical contact between the wire and the wire connection point on the lock head. This arrangement buffers the direct mechanical stress exerted on the circuit board by the tension of the wire, thus ensuring the stability of the electrical contact of the conductive circuit under harsh transportation environments such as vibration and impact.

[0018] In a preferred embodiment, the main control circuit further includes a state mapping module, which maps the “locked” or “unlocked” state of the wire seal and the number of uses to the user area of ​​the storage unit connected to the NFC radio frequency circuit.

[0019] In a preferred embodiment, the wire detection module is further configured to enter a low-power standby mode when the wire seal is locked, and to detect changes in the continuity or tension value of the conductive circuit. F t The device is activated when its rate of change exceeds a preset threshold. This setting reduces the overall power consumption of the seal and extends its lifespan.

[0020] In a preferred embodiment, the main control circuit is further configured to debounce changes in the on / off state of the conductive circuit, only performing the state switching and usage count increment operations on the wire seal after confirming a change in the stable state of the conductive circuit. This configuration avoids misjudgments caused by vibration or momentary poor contact, improving the reliability of state determination.

[0021] Another aspect of the present invention provides an NFC-based wire seal monitoring system, including a reusable NFC wire seal as described above, and an NFC reader / writer, wherein the NFC reader / writer is used to approach the reusable NFC wire seal to read the current status and number of uses transmitted by the NFC radio frequency circuit in a contactless manner.

[0022] Another aspect of the present invention provides a monitoring method based on the above-mentioned reusable NFC wire seal, comprising the following steps: Tension and current acquisition steps: Real-time acquisition of the real-time tension value of the steel wire in the steel wire seal. F tReal-time current value of the conductive circuit made of steel wire I t .

[0023] Weighted discrimination step: based on preset weight coefficients α and β Combined with the standard initial tension value of the sealing time F std Rated current value under normal closed state of conductive circuit I std Execution-Electricity Dual-Mode Weighted Discrimination Algorithm:

[0024] State determination and recording steps: Based on the calculation results of the discrimination algorithm S ( t Determine whether the wire seal is in a "locked" or "unlocked" state, and record the number of times it is used when the state changes.

[0025] Near Field Communication Steps: In response to polling by an external NFC reader / writer, the current status and number of uses are sent out via the NFC communication protocol.

[0026] In a preferred embodiment of the present invention, the weighted discrimination step further includes: when the real-time tension value F t Deviation from standard initial tension value F std The amplitude exceeds the first threshold, or the real-time current value I t Deviation from rated current value I std The magnitude exceeds the second threshold, or the calculation result S ( t If the signal exceeds the preset normal working range, the wire seal is determined to be in an abnormal or tampered state.

[0027] In a preferred embodiment of the present invention, in the weighted discrimination step, the weight coefficients... α and β These are variable parameters preset based on the application scenarios of the wire seal. In scenarios where the primary risk is preventing violent shearing, the tension weighting coefficient... α Configured to be greater than the current weighting factor β In scenarios where electrical bypass attacks are the primary risk, the current weighting coefficient... β Configured to be greater than the tension weighting factor α .

[0028] Compared with the prior art, the present invention has the following beneficial effects: By introducing a force-electric dual-mode weighted discrimination algorithm, the mechanical tension of the steel wire and the current parameters of the conductive circuit are fused for judgment. This not only identifies violent damage such as the steel wire being cut, which causes the circuit to break, but also detects "soft damage" where the steel wire is partially damaged but the circuit remains conductive, as well as electrical attack behaviors such as parallel bypass, thus improving the anti-tampering judgment capability. At the same time, the funnel ball self-locking mechanism built into the lock head and the floating electrical contact design of the screw realize the separation of the electronic module and the consumable steel wire, supporting the recycling of the signature body and reducing the cost of use. In addition, the spatial isolation layout of the double-sided PCB optimizes the performance of the NFC antenna, enabling stable communication in a metal environment.

[0029] Furthermore, the above summary does not enumerate all the features required for embodiments of the present invention, and other combinations of these feature groups may also constitute embodiments of the present invention. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the background art, the drawings used in the embodiments of the present invention or the background art will be described below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the overall assembly of a reusable NFC wire seal in one embodiment of the present invention.

[0032] Figure 2 for Figure 1 A schematic diagram of the top cover.

[0033] Figure 3 for Figure 1 A schematic diagram of the middle and bottom shell.

[0034] Figure 4 for Figure 1 A schematic diagram of the front of the circuit board.

[0035] Figure 5 for Figure 1 A schematic diagram of the back of the circuit board.

[0036] Figure 6 for Figure 1 A diagram of the screw and lock.

[0037] Figure 7 This is a flowchart illustrating a monitoring method for reusable NFC wire seals according to one embodiment of the present invention.

[0038] The components are as follows: 1. Top cover, 2. Bottom shell, 3. Circuit board, 4. Lock head, 5. Screw, 6. QR code printing area, 7. NFC scanning area, 8. Lock head compartment, 9. Circuit board compartment, 10. Wire connection contact point, 11. Steel wire detection module, 12. Main control circuit, 13. NFC radio frequency circuit, 14. Battery, 15. NFC antenna. Detailed Implementation

[0039] To make the technical means, creative features, objectives and effects of the embodiments of the present invention easier to understand, the embodiments of the present invention are further described below in conjunction with the figures and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the embodiments of the present invention and are not intended to limit the embodiments of the present invention.

[0040] It should be noted that in the embodiments of the present invention, the terms "upper", "lower", "inner", "outer", "front", "back", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0041] To better understand the embodiments of the present invention, please refer to Figures 1 to 6 As shown, this embodiment provides a reusable NFC wire seal, which mainly consists of a top cover 1, a bottom shell 2, a circuit board 3, two lock heads 4, and screws 5.

[0042] The top cover 1 and the bottom shell 2 are fixedly connected by means of snaps or ultrasonic welding, and together they form the outer shell of the seal. The outer surface of the top cover 1 is divided into a QR code printing area 6 and an NFC scanning area 7. The QR code printing area 6 can be used to print the unique number, batch and other information of the seal, which is easy to identify and scan. The NFC scanning area 7 is used to indicate the proximity of an external NFC reader.

[0043] See Figure 2 and Figure 3 The internal structure of the bottom shell 2 is divided into two independent lock head compartments 8 and a circuit board compartment 9. Two lock heads 4 are fixedly installed in the two lock head compartments 8, and each lock head 4 has a funnel-shaped self-locking mechanism. The specific structure of this self-locking mechanism is as follows: the lock head 4 has a conical funnel-shaped channel inside, within which a movable ball or roller is placed. When a steel wire is inserted from the front end, the ball is pushed away from the conical narrow section, allowing the steel wire to pass smoothly; when the steel wire attempts to be pulled out in the opposite direction, the ball is moved by the steel wire towards the conical narrow section, thus being wedged and firmly locking the steel wire.

[0044] In one feasible embodiment, the aforementioned funnel-shaped self-locking mechanism can also adopt the following variant structure: a conical channel is provided inside the lock head, and an elastic gripper assembly is provided inside the channel. When the steel wire is inserted from the front end, the elastic gripper is opened to allow the steel wire to pass through; when the steel wire attempts to be pulled out in the opposite direction, the elastic gripper contracts radially under the action of spring force, wedging and locking the steel wire.

[0045] In one feasible embodiment, the screw 5 is used to fix the end of the steel wire to the lock head 4 and to make the steel wire and the wire connection point 10 on the lock head 4 form a floating electrical contact. The floating electrical contact can also adopt the following structure: the lock head 4 is provided with an elastic metal spring, the end of the steel wire is pressed onto the elastic metal spring by the screw 5, and the spring is then connected to the wire connection point 10 of the circuit board 3 through the wire. The elastic spring can further absorb the mechanical energy generated by the vibration of the steel wire and improve the long-term stability of the electrical contact.

[0046] Circuit board 3 is located inside circuit board compartment 9, see [link / reference] Figure 1 , Figure 4 and Figure 5 The circuit board 3 is a double-sided printed circuit board. Its front side integrates the main control circuit 12, NFC radio frequency circuit 13, battery 14, and wire detection module 11, while the back side houses the NFC antenna 15. The battery 14, located on the front side of the circuit board 3, powers the main control circuit 12 and NFC radio frequency circuit 13. It is noteworthy that the NFC antenna 15's position on the back of the circuit board 3 corresponds vertically to the NFC scanning area 7 on the top cover 1. This arrangement spatially isolates the NFC antenna 15 from the densely arranged components on the front side, such as the main control circuit 12 and NFC radio frequency circuit 13. In this embodiment, this layout reduces near-field electromagnetic interference from high-frequency digital circuits to the NFC antenna 15, thereby optimizing antenna impedance matching and improving the read / write distance and sensitivity of NFC communication.

[0047] In one feasible implementation, see Figure 3 , Figure 4 and Figure 6 The circuit board 3 is provided with wire connection contact point 10. The wire detection module 11 forms a complete conductive circuit with the lock head 4 and the wire passing through the two lock heads 4 through the wire connection contact point 10.

[0048] Specifically, screw 5 is used to fix the end of the steel wire to the lock head 4. During assembly, the steel wire is first passed through the funnel-shaped self-locking mechanism of the two lock heads 4 in sequence, and then the steel wire is tightened to give it a certain initial tension. Next, screw 5 is used to press and fix the end of the steel wire to the lock head 4. At the same time, the two ends of a wire are respectively connected to the conductive parts on the lock head 4 and the wire connection contact point 10 on the circuit board 3. In this way, a closed loop is formed: "steel wire detection module 11 - wire connection contact point 10 - wire - lock head 4 - steel wire - another lock head 4 - wire - wire connection contact point 10 - steel wire detection module 11".

[0049] Most importantly, screw 5 is used to fix the end of the steel wire and form an electrical contact between the steel wire and the wire connection point 10 on the lock head 4, rather than fixing screw 5 directly to the bottom shell 2. This "floating" electrical contact design means that when the steel wire is subjected to external tension or vibration, the mechanical stress generated is mainly transmitted to the lock head 4 through screw 5, and will not directly act on the wire connection point 10 on the circuit board 3. This setting buffers the direct impact of the steel wire tension on the circuit board 3, avoids solder joint detachment or circuit board damage caused by long-term vibration or violent pulling, and improves the long-term electrical contact stability of the conductive circuit and the overall reliability of the product.

[0050] In one possible application scenario, see Figure 4 and Figure 7 The main control circuit 12 on circuit board 3 (e.g., a low-power ARM or RISC architecture microcontroller) has a built-in control program configured to execute a monitoring process to monitor the integrity of the wire seal in real time. This process specifically includes the following steps: Step S1: Data Collection The main control circuit 12 controls the wire detection module 11 to collect the following two types of data in real time at a preset period (e.g., every 1 second or every 10 seconds): Tension data: The real-time tension value of the steel wire is acquired through the miniature strain gauge tension sensor integrated inside the steel wire detection module 11. F t The tension sensor is attached to the contact surface between the lock head 4 and the steel wire, and can detect minute stress changes in the steel wire caused by external tension or deformation, with a measurement accuracy of ±0.5N.

[0051] Current data: The real-time current value of the conductive circuit is acquired in real time through the precision sampling resistor and differential amplifier integrated inside the wire detection module 11. I t Specifically, the wire detection module 11 applies a constant test voltage (e.g., 3.3V) to the conductive circuit, and calculates the circuit current value by detecting the voltage drop across the sampling resistor. I tThe sampling accuracy reaches ±0.01mA.

[0052] In one feasible implementation, the wire detection module 11 also has the following functions: 1) High-resolution current sampling: It can detect current fluctuations in the conductive circuit caused by minute changes in the resistance of the steel wire itself in real time. When the steel wire is tightened, loosened or pulled by an external force, the contact pressure between the steel wire and the lock head 4 and the degree of deformation of the steel wire itself change, resulting in a minute but measurable change in the ohmic resistance of the steel wire (for example, the resistance change rate is between 0.1% and 5%).

[0053] 2) Abnormal behavior identification: By continuously monitoring real-time current values I t The changing trend and fluctuation range, and the relationship with the rated current value I std By comparing, the following anomalous behaviors can be identified: The wire is tightened: the increased tension in the wire stretches the metal lattice structure, causing a slight increase in resistivity and resulting in a change in the loop current. I t A repeatable slight decrease occurs (e.g., a decrease of 0.5% to 2%).

[0054] The steel wire is loosened or pulled: The steel wire and the funnel-shaped self-locking mechanism inside the lock head 4 experience relative displacement, causing a transient change in contact resistance, which leads to… I t A brief spike or step change occurs (e.g., the spike lasts for less than 10 milliseconds and the amplitude change exceeds 5%).

[0055] Repeated micro-movements: When the steel wire is repeatedly pulled out, the main control circuit 12 records... I t Multiple abnormal fluctuations, combined with tension value F t The rate of change (e.g., a rate of change exceeding 5 N / s) is used to comprehensively determine whether there is any deliberate, exploratory damage.

[0056] 3) Temperature Compensation Mechanism: The wire detection module 11 has a built-in temperature sensor (not shown in the figure) for real-time acquisition of ambient temperature. When the ambient temperature changes, the main control circuit 12 adjusts the real-time current value according to the preset temperature-resistance compensation curve. I t Corrections were made to eliminate the impact of temperature drift on current sampling and improve the accuracy of the judgment.

[0057] Step S2: Calculation steps The main control circuit 12 acquires the following pre-stored reference data: Standard initial tension value Fstd After the seal is first locked and tightened by screw 5, the system automatically records and stores the initial average tension value. Specifically, the main control circuit 12 has a preset calibration mode. In calibration mode, after detecting that both locking heads 4 have completed wire threading and the self-locking mechanism has engaged, the main control circuit 12 continuously collects 10 tension values, removes the maximum and minimum values, and takes the average value as the final value. F std It is stored in non-volatile memory.

[0058] Rated current value I std Upon initial sealing, the main control circuit 12 applies a standard test voltage to the conductive circuit and collects the current value after the circuit stabilizes, as... I std Stored in non-volatile memory. This value reflects the inherent resistance characteristics of the current steel wire; different batches and different materials of steel wire may have different resistance characteristics. I std This enables adaptive calibration for different consumables.

[0059] Weighting coefficient α and β Based on the application scenario, it meets the following requirements. α+β =1. For example, the default setting in a typical transportation scenario is 1. α=0.6，β=0.4 .

[0060] Subsequently, the main control circuit 12 will collect data in real time. F t and I t Substituting the following force-electric dual-mode weighted discrimination algorithm, the comprehensive state value is calculated. S(t) : S(t) = α(F t / F std )+β(I t / I std ) In a preferred embodiment, the main control circuit 12 is further configured to perform component calculations of the force-electric dual-mode discrimination algorithm to obtain the mechanical monitoring components. S 1 (t) and electrical monitoring components S 2 (t) : S 1 (t) = α(Ft / F std ) S 2 (t) = β(I t / I std ) The main control circuit 12 can be based on... S 1 (t), S 2 (t) Independent anomaly detection can be performed, or the overall state detection value after weighted fusion can be used. S(t) Perform overall state determination to achieve multi-level anomaly detection. For example, when S 1 (t) abnormal but S 2 (t) Under normal circumstances, a situation may occur where the steel wire is partially damaged but the circuit remains conductive; when S 1 (t) Normal but S 2 (t) In case of anomalies, an electrical bypass attack may have occurred. By combining component monitoring with integrated judgment, the granularity and accuracy of anti-tampering detection are further improved.

[0061] In one feasible implementation, the weighting coefficients α and β can be dynamically adjusted according to the transportation environment. When the accelerometer detects that the vibration intensity exceeds the preset threshold Gmax (e.g., 2g), the main control circuit 12 automatically reduces the tension weight α and increases the current weight β to filter out instantaneous tension spikes (lasting less than 20 milliseconds) caused by vehicle bumps, making the determination of S(t) more accurate. The adjustment range is proportional to the vibration intensity; the stronger the vibration, the greater the decrease in α and the greater the increase in β. This algorithm weights and fuses the mechanical monitoring components and the electrical monitoring components. The main control circuit 12 can also independently determine the anomalies of the mechanical monitoring components and the electrical monitoring components, or determine the overall state based on the weighted and fused comprehensive state determination value, thus realizing multi-level anomaly detection.

[0062] Step S3: Judgment and Recording Steps The main control circuit 12 will calculate S(t)It is compared with the preset normal operating range, such as [0.8, 1.2]. This range is an empirical value derived from a large amount of experimental data and can cover various fluctuations under normal transportation conditions (including temperature and humidity changes, slight vibrations, battery voltage drops, etc.).

[0063] The decision logic is as follows: Normal judgment: If S(t) If the seal remains within the normal operating range, it is determined to be in a normal "locked" state. At this time, the main control circuit 12 does not perform any state switching operation, but only records the measurement result and timestamp in a temporary buffer for subsequent auditing and tracing.

[0064] Anomaly detection: If S(t) Outside the normal operating range (e.g.) S(t) <0.8 or S(t) If the seal is found to be in an "unlocked" or tampered state, or if any of the following conditions are met: >1.2), the seal is determined to be in an abnormal state: F t A sharp decline occurred: the decline exceeded the initial value. F std 30% of the duration, and lasting longer than 50 milliseconds (de-jitter time).

[0065] I t A sudden change occurs: the current drops to zero (the circuit is broken) or increases abnormally (e.g., exceeding...). I std 20% of that.

[0066] F t and I t Simultaneous abnormal fluctuations, such as a decrease in tension accompanied by a jump in current, further confirm the authenticity of the abnormal event.

[0067] State transition and usage count recording: Once the state changes from "locked" to "unlocked", the usage count counter inside the main control circuit 12 automatically increments by 1. Simultaneously, the main control circuit 12 records the state transition event, the transition timestamp (accurate to milliseconds), and the usage counts before and after the transition. F t and I t Value, and current S(t) The value is recorded in the event log of the non-volatile memory.

[0068] In one feasible implementation, the main control circuit 12 is also configured to debounce changes in the on / off state of the conductive loop. Specifically, when a change in the loop state is detected (e.g., from on to off), the system does not respond immediately but instead starts a short timer (e.g., 10-50 milliseconds). Only if the loop state remains unchanged after the timer expires is the change confirmed as valid, and then the state switching and usage count increment operations are performed. This debounce process effectively avoids erroneous triggering caused by vibrations or momentary poor contact during transportation (e.g., the wire and lock momentarily losing contact due to vehicle bumps, lasting less than 5 milliseconds), ensuring the authenticity and reliability of the state record.

[0069] Step S4: Communication Steps When an external NFC reader (e.g., a smartphone or dedicated handheld terminal with NFC functionality) approaches the NFC scanning area 7 of the top cover 1 (typically within a range of 0-5 cm), the following process occurs: Energy Coupling and Wake-up: The NFC antenna 15 couples to the radio frequency field energy emitted by the NFC reader, generating an induced electromotive force. This electromotive force, after rectification and voltage regulation, provides instantaneous operating power to the core components of the NFC radio frequency circuit 13 and the main control circuit 12. During this process, the seal can respond to the reader's polling without a built-in battery (passive operating mode); if a battery 14 is provided, a longer communication distance (up to 10 cm) can be obtained in active mode.

[0070] Data Reading: After the NFC radio frequency circuit 13 is woken up, the main control circuit 12 controls it to read the status information and usage count data stored in the user area. Specifically, the main control circuit 12 reads the data from the storage unit (such as the EEPROM or FRAM of the NFC chip) through the internal bus and encapsulates it according to the NFC data exchange format.

[0071] Data transmission: The NFC radio frequency circuit 13 modulates the packaged data through the NFC antenna 15 and transmits it to an external NFC reader / writer. The transmitted data content includes, but is not limited to: Current status of the seal: "Locked" or "Unlocked".

[0072] Usage count: An integer accumulated starting from the initial value of 0, with a maximum of 65535 times.

[0073] Unique Seal Identifier: A unique serial number stored in the UID area of ​​the NFC chip, which cannot be changed.

[0074] Optional data: timestamp of the most recent state transition, event log summary, etc.

[0075] Interactive feedback: After receiving data, the external NFC reader displays the seal status and number of uses through its application interface. Operators can quickly learn about the current status and historical number of uses of the seal through a mobile phone or other common terminal without opening the seal shell, thus achieving contactless and efficient verification.

[0076] In one feasible implementation, the NFC radio frequency circuit 13 also supports an anti-collision protocol, which allows the reader to identify and read multiple seals one by one when they exist in the same radio frequency field at the same time, thus avoiding signal conflicts caused by multiple seals responding at the same time.

[0077] In a preferred embodiment, the main control circuit 12 is further preset with a calibration mode and a monitoring mode: Calibration Mode: When the two locking heads 4 are detected to have completed wire threading and the self-locking mechanism is engaged, the main control circuit 12 automatically enters calibration mode. In this mode, the system continuously collects 10 tension values, removes the maximum and minimum values, and takes the average value as the reference tension. F std Store the data; simultaneously, apply a standard test voltage (e.g., 3.3V) to the circuit and collect the current value after the circuit stabilizes, using it as the reference current. I std Storage. The calibration process takes approximately 1-2 seconds. Once completed, the system automatically switches to monitoring mode. Through adaptive calibration, steel wire consumables of different batches and resistance values ​​can be accurately adapted without the need for manual parameter input.

[0078] Monitoring Mode: After calibration, the main control circuit 12 enters a low-power monitoring mode. In this mode, the core components of the wire detection module 11 and the main control circuit 12 enter a sleep state, retaining only an extremely low-power timer (power consumption less than 1μA) for periodic wake-up. The wake-up period can be configured according to the application scenario, for example: High-security scenario: wakes up once every 1 second for real-time monitoring.

[0079] Typical scenario: wake up every 10 seconds to balance power consumption and real-time performance.

[0080] Low power consumption scenario: wakes up every 60 seconds, suitable for long-term warehouse monitoring.

[0081] Only when a change in the continuity or tension value of the conductive circuit is detected F t The system will only be instantly woken up and execute the complete discrimination and recording process when the rate of change exceeds a preset threshold (e.g., 5 N / s). This setting allows the seals powered by button batteries (e.g., CR2032, nominal capacity 220mAh) to have a standby and working life of more than 5 years (calculated based on 8640 wake-ups per day).

[0082] In monitoring mode, the main control circuit 12 periodically performs monitoring and judgment according to the process of steps S1 to S4. The specific details have been described in detail in the aforementioned steps and will not be repeated here.

[0083] In some implementations, see Figure 7 Based on the aforementioned reusable NFC wire seal, this embodiment of the invention also provides a monitoring method, which mainly includes the following steps: Step S1 (Tension and Current Acquisition Step): The steel wire detection module 11 acquires the real-time tension value of the steel wire in the steel wire seal. F t Real-time current value of the conductive circuit made of steel wire I t .

[0084] Step S2 (Weighted Judgment Step): The main control circuit 12 is based on preset weighting coefficients. α and β Combined with the standard initial tension value of the sealing time F std Rated current value under normal closed state of conductive circuit I std Execution-Electricity Dual-Mode Weighted Discrimination Algorithm:

[0085] Step S3 (State Determination and Recording): The main control circuit 12 determines the state based on the calculation results of the discrimination algorithm. S(t) The system determines whether the wire seal is in a "locked" or "unlocked" state. When the state changes (for example, from "locked" to "unlocked"), the usage counter inside the main control circuit 12 automatically increments to record the usage.

[0086] Step S4 (Near Field Communication Step): In response to the radio frequency field polling of the external NFC reader, the NFC radio frequency circuit 13 is woken up and transmits the current status and usage count data stored in the user area to the external reader via the NFC antenna 15 through the NFC communication protocol.

[0087] In one feasible implementation, the aforementioned weighting coefficients α and β It is configured as a variable parameter that can be preset and adjusted according to the specific application scenario of the wire seal.

[0088] For example, when this seal is applied to scenarios where the primary risk is preventing violent cutting (such as large container shipping), the tension weighting coefficient can be adjusted. α Configured to be greater than the current weighting factor β For example, setting α =0.7, β=0.3, thus making the system more sensitive to changes in tension.

[0089] For example, when this seal is used in scenarios where there is a risk of electrical bypass attacks (such as the transportation of high-value electronic components), the current weighting coefficient can be adjusted. β Configured to be greater than the tension weighting coefficient α For example, setting α =0.3, β =0.7, which makes the system more sensitive to small current anomalies in the loop.

[0090] In this embodiment, this adaptive configuration enables the seal to flexibly adapt to the security requirements of different logistics environments, thus expanding the product's applicability.

[0091] In one feasible implementation, the wire detection module 11 also has a low-power management function. When the wire seal is in a stable "locked" state, the core parts of the wire detection module 11 and the main control circuit 12 enter a low-power standby mode, retaining only an extremely low-power timer for periodic wake-up. The module only wakes up when a change in the continuity of the conductive circuit or a change in tension value is detected. F t The system will only be instantly activated and execute the complete discrimination and recording process when the rate of change exceeds a preset threshold. This setting allows the button battery-powered seals to have a standby and working life of several years.

[0092] Furthermore, the main control circuit 12 is configured to debounce changes in the on / off state of the conductive loop. Specifically, when a change in the loop state is detected, the system does not respond immediately but instead starts a short timer (e.g., 10-50 milliseconds). Only if the loop state remains unchanged after the timer expires is the change considered valid, and then the state switching and usage count increment operations are performed. In this embodiment, this debounce processing avoids erroneous triggering caused by vibrations or momentary poor contact during transportation, ensuring the authenticity and reliability of the state record.

[0093] In a specific application scenario, a multinational logistics company needs to transport a batch of high-value integrated circuit chips from a first port city to a second port city. The goods are extremely sensitive to vibration and unauthorized opening, and may pass through multiple transit ports during transportation, posing a risk of electrical bypass attacks.

[0094] The logistics company uses the reusable NFC wire seal of this invention to seal boxes. The operation steps are as follows: 1. Initialization and Locking: The operator passes the steel wire sequentially through the funnel-shaped self-locking mechanism of the two lock heads and tightens it to the predetermined tension value. F std=50N, at this time, the conductive circuit is normally closed, and the rated current value is... I std =10mA, the main control circuit records these two initial values ​​and marks the seal status as "locked", and records the number of uses as "1". The operator scans the NFC scanning area on the top cover with an NFC-enabled mobile phone to read and confirm that the seal status is normal.

[0095] 2. Monitoring during transportation: During transportation, the seal enters a low-power standby mode. The main control circuit wakes up every 10 seconds to collect real-time tension values. F t and real-time current value I t And calculate the comprehensive state value. S(t) =0.6×( F t / 50)+0.4×( I t / 10), under normal transportation conditions S(t) It remained stable within the normal operating range of 0.95-1.05, and the seal continuously reported a "locked" status.

[0096] 3. Inspection upon arrival at the destination: After the goods arrive at the second port city, customs officers use a universal NFC-enabled mobile phone to approach the seal. The phone screen immediately displays: "Seal status: Locked; Number of uses: 1; Status normal." After comparison with the record at the time of loading, the goods are released.

[0097] In this application scenario, operators do not need special equipment; they can complete the quick inspection using only their mobile phones. The force-electric dual-mode algorithm stably outputs the normal status under normal conditions.

[0098] In a specific application scenario, to verify the ability of this invention to detect violent cutting behavior, the following simulation test was conducted: A tester attempted to cut a wire that was in a "locked" state using wire cutters. At the moment of cutting: Physical level: Real-time tension value of steel wire F t From the standard F std =50N instantly dropped to F t ≈0N.

[0099] Electrical level: The conductive circuit is broken, real-time current value I t From the standard I std =10mA dropped to I t =0mA.

[0100] Algorithm determination: After the main control circuit collects the above data, it calculates... S(t) = 0.6 × (0 / 50) + 0.4 × (0 / 10) = 0, which is far below the lower limit of the normal working range (e.g., 0.8).

[0101] Status recording and communication: The main control circuit immediately marks the internal status as "unlocked" and increments the usage count counter from "1" to "2". Subsequently, when any NFC reader or writer approaches, it will read the information "Status: Unlocked; Usage Count: 2".

[0102] In this application scenario, the seal of this invention successfully identified the act of forcibly cutting the wire and automatically recorded the tampering event. Even if criminals attempt to reconnect the wire, the manager can detect the abnormal number of uses due to the increasing number of uses.

[0103] In a specific application scenario, to verify the detection capability of this invention against electrical bypass attacks, the following simulation test was conducted: A criminal attempted to bypass the original conductive circuit without cutting the steel wire by connecting a wire in parallel, in order to simulate the illusion that the circuit was still conductive. The specific operation was to connect a wire with a resistance of about 5Ω in parallel to each end of the steel wire.

[0104] From an electrical perspective: After connecting the wires in parallel, the total resistance of the entire conductive loop changes. According to the principle of parallel circuits, the total resistance of the loop decreases, and the real-time current value... I t From the standard I std =10mA rises to I t ≈15mA.

[0105] Physical aspect: Because the steel wire was not cut, the real-time tension value of the steel wire... F t Stay F std = Around 50N, the variation is small.

[0106] Algorithm determination: The main control circuit collected... F t ≈50N I t After approximately 15mA, calculate S(t) =0.6×(50 / 50)+0.4×(15 / 10)=0.6×1+0.4×1.5=0.6+0.6=1.2. This value exceeds the upper limit of the normal working range (e.g., 1.1). The seal is judged as an abnormal state, the internal status is marked as "unlocked", and the number of uses is incremented.

[0107] In this application scenario, the force-electric dual-mode weighted discrimination algorithm of this invention successfully identified electrical bypass attacks that could not be detected by loop continuity detection alone, due to the weighting coefficients. β The presence of 0.4 indicates that the abnormal rise in current is captured, proving that the algorithm of this invention has high sensitivity to electrical attacks.

[0108] In another specific application scenario, in order to further verify the necessity of the technical solution of this application from the reverse perspective, the following comparative example is set up.

[0109] This comparative example fully reproduces the prior art solutions mentioned in the background (such as WO2016033914A1), that is, the use of NFC tamper-evident seals that "only monitor the continuity of the circuit" to illustrate the technical problems that arise when the key technical features of this application are missing.

[0110]

[0111] Comparative conclusion: As can be seen from the above comparison, the existing technical solution that relies solely on circuit continuity detection cannot identify anomalies when faced with advanced attack methods such as parallel bypass and partial damage to the steel wire, posing serious security risks. In contrast, the present invention improves the anti-tampering capability of the seal by introducing a force-electric dual-mode weighted discrimination algorithm, which integrates physical tension and electrical parameters for judgment.

[0112] In other specific application scenarios, the weighting coefficients of this invention α and β It can be adaptively configured according to different logistics scenarios to optimize detection sensitivity.

[0113] Scenario 1: Scenarios primarily focused on preventing violent sabotage (such as bulk cargo transportation). In such scenarios, the transportation environment is harsh, and the steel wire is more susceptible to violent shearing or mechanical impact, but the risk of electrical attack is low. Therefore, the algorithm parameters can be configured as follows: α =0.8, β =0.2, making the system more sensitive to changes in tension.

[0114] When the tension of the steel wire decreases due to an external impact, the calculated S ( t The value will decrease rapidly due to the high weight of the tension term, thus triggering an alarm in a timely manner.

[0115] Scenario 2: Scenarios primarily focused on preventing electrical attacks (such as transporting high-value electronic products). In such scenarios, where the goods are of high value, criminals tend to employ covert electrical bypass methods to crack the code. Therefore, the algorithm parameters can be configured as follows: α=0.3，β=0.7， This makes the system more sensitive to changes in current.

[0116] When criminals attempt to bypass the circuit using parallel wires, the increased weight of the current term makes... S ( t The increase in () is more significant and more easily detected as abnormal.

[0117] Through the above adaptive configuration, the seal of this embodiment can flexibly adapt to the security requirements of different logistics environments, avoiding oversensitivity in low-risk scenarios (reducing false alarms) and ensuring high sensitivity in high-risk scenarios (reducing false alarms), demonstrating the flexibility of the present invention.

[0118] It should be understood that the terms "one embodiment," "an embodiment," "a feasible implementation," or "some implementations" used throughout the specification mean that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present invention. Therefore, "one embodiment," "an embodiment," "a feasible implementation," or "some implementations" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also recognize that the embodiments described in the specification are optional embodiments, and the actions and modules involved are not necessarily essential to the embodiments of the present invention.

[0119] The above description is merely a specific embodiment of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be determined by the protection scope of the claims.

Claims

1. A reusable NFC wire seal, characterized in that, include: The outer shell is formed by the top cover (1) and the bottom shell (2); The circuit board (3) is located in the circuit board compartment (9) inside the outer shell. The circuit board (3) includes a main control circuit (12), an NFC radio frequency circuit (13), an NFC antenna (15), and a wire detection module (11). The lock head (4) is provided with a pair of independent lock head compartments (8) respectively located on the bottom shell (2), and each lock head (4) is provided with a funnel ball self-locking mechanism for allowing the steel wire to pass through in one direction; The steel wire detection module (11) forms a conductive circuit with the two lock heads (4) and the steel wire passing through the two lock heads (4) through the contact point (10) connected by the wire; The main control circuit (12) is configured to perform the following steps to monitor the status of the wire seal in real time: Data acquisition steps: The tension value of the steel wire is acquired in real time through the steel wire detection module (11). F t and the current value of the conductive circuit I t ; Calculation steps: Based on the preset weighting coefficients, combined with the standard initial tension value during the sealing timing. F std and the rated current value of the conductive circuit under normal closed state I std Calculate the comprehensive state value S(t); Judgment and Recording Steps: Determine the current state of the wire seal based on the comprehensive state value S(t), and record the number of uses when the state changes; Communication steps: Control the NFC radio frequency circuit (13) to send the current status and number of uses to the external reader / writer through the NFC antenna (15); The main control circuit (12) is configured to execute the following force-electric dual-mode weighted discrimination algorithm to calculate the comprehensive state value. S(t) : ; in, F t The tension value of the steel wire is collected in real time. F std The standard initial tension value for signing the sealing time. I t The current value of the conductive circuit is collected in real time. I std This is the rated current value under the normal closed state of the conductive circuit. α and β These are preset weighting coefficients, and the weighting coefficients α and β can be dynamically adjusted according to the transportation environment. α+β =1; When the accelerometer detects that the vibration intensity exceeds the preset threshold, the main control circuit (12) automatically reduces the weighting coefficient. α And increase the weighting coefficient β Furthermore, the adjustment range is directly proportional to the vibration intensity; the stronger the vibration, the greater the decrease in α and the greater the increase in β. When the tension value F t Deviation from the standard initial tension value F std The amplitude exceeds the first threshold, or the current value I t Deviation from the rated current value I std The magnitude exceeds the second threshold, or the calculation result S(t) If the value exceeds the preset normal working range, the wire seal is determined to be in an abnormal or tampered state.

2. The reusable NFC wire seal according to claim 1, characterized in that, The circuit board (3) is a double-sided printed circuit board. The main control circuit (12), the NFC radio frequency circuit (13) and the wire detection module (11) are integrated on the front side, and the NFC antenna (15) is provided on the back side. The outer surface of the top cover (1) is provided with an NFC scanning area (7). The position of the NFC antenna (15) corresponds to the NFC scanning area (7) in the vertical direction, so that the NFC antenna (15) forms a spatial isolation between the main control circuit (12) and the NFC radio frequency circuit (13).

3. The reusable NFC wire seal according to claim 1, characterized in that, It also includes screws (5) for fixing the end of the wire to the lock head (4) and making the wire and the wire connection point (10) on the lock head (4) form a floating electrical contact to buffer the direct mechanical stress of the wire tension on the circuit board (3).

4. The reusable NFC wire seal according to claim 1, characterized in that, The main control circuit (12) also includes a state mapping module, which is used to map the "locked" or "unlocked" state of the wire seal and the number of uses to the user area of ​​the storage unit connected to the NFC radio frequency circuit (13).

5. The reusable NFC wire seal according to claim 1, characterized in that, The wire detection module (11) is also used to enter a low-power standby mode when the wire seal is in a locked state, and to detect changes in the continuity of the conductive circuit or the tension value. F t It is activated when the rate of change exceeds a preset threshold.

6. The reusable NFC wire seal according to claim 1, characterized in that, The main control circuit (12) is also configured to perform debouncing processing on the on / off state changes of the conductive circuit, and only after confirming that the stable state of the conductive circuit has changed will the state switching of the wire seal and the incrementing operation of the number of uses be performed.

7. A monitoring system based on reusable NFC wire seals, characterized in that, include: Reusable NFC wire seal as described in any one of claims 1 to 6; And an NFC reader / writer, which is used to approach the reusable NFC wire seal to read the current status and the number of uses transmitted by the NFC radio frequency circuit (13) in a contactless manner.

8. A monitoring method based on reusable NFC wire seals, characterized in that, The monitoring method, applied to reusable NFC wire seals as described in any one of claims 1 to 6, comprises the following steps: Tension and current acquisition steps: Real-time acquisition of the real-time tension value of the steel wire in the steel wire seal. F t Real-time current value of the conductive circuit made of steel wire I t ; Weighted discrimination step: based on preset weight coefficients α and β Combined with the standard initial tension value of the sealing time F std Rated current value under normal closed state of conductive circuit I std Execution-Electricity Dual-Mode Weighted Discrimination Algorithm: ; State determination and recording steps: Based on the calculation results of the discrimination algorithm S ( t The system determines whether the wire seal is in a "locked" or "unlocked" state and records the number of uses when the state changes. Near Field Communication Steps: In response to polling by an external NFC reader / writer, the current status and the number of uses are sent out via the NFC communication protocol.

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