Electronic Anti-theft Tags Automatic Detection Technology and Systems Research
|School||Hangzhou University of Electronic Science and Technology|
|Course||Detection Technology and Automation|
|Keywords||EAS system an electronic tag detection system mutual inductance coupling digital filter|
At present, most domestic manufactures of electronic tags face many problems in the quality testing links of the electronic tag, such as detection methods are backward, working in low efficiency and not high degree of automation, and it can not provide a reliable, accurate figures. So this paper studies and presents an electronic tag automatic detection system based on the principle of mutual inductance coupling.First, the article analyzes the composition and working principle of the EAS system. Electronic tags as an integral part of the EAS system are identified by the detector. This 1-bit transponder, only gives information on the availability of electronic tags, unable to provide additional technical data on the tags. Therefore, quality testing of electronic tags can’t be achieved only by using the EAS system; it needs the further research to improve detection techniques.In the detection method of electronic tags, this system references to the identification technology of the EAS system, detection of the basic principles are still using mutual inductance coupling. To this end, this paper proposes two kinds of detection methods, single-coil detection model and double-coil detection model, and carries out theoretical derivation and mathematical simulation modeling under the MATLAB software, to show the impact of the two methods on the obtaining the detection parameters, finally establish this double-coil model as the system test technical solution. In this model the transfer function waveform is provided, after combining the system requirements, we designed the occurrence of the sweep signal source, and finished the detection method for electronic tags.Studying the requirements offering by the manufactures of electronic tags, the paper finished the overall design for this electronic tag automatic detection system. But in the actual production environment, EMI is very strong. So this issue also has anti-jamming system, digital filter processing research, and using a sliding mean filter and a pulse peak filtering approach, to filter frequency interference, pulse interference and system instability error. The actual data also verified this approach to good results.The core of the system’s hardware use the LPC2214 processor which is in the ARM architectures, the sweep signal part is adopted the direct digital frequency synthesis technique, and achieve the occurrence of high-quality signal. The system is also coupled with storage, data acquisition, communications and control peripherals to perfect the system function. Multip-processor designing separate the man-machine interface control part from the system, this upgrade the system’s processing speed, and enhance the operational efficiency of the system. In the software, the system madeμC/OS-II as the operating platform. Over the realization of the relevant hardware drivers, the system complete the sweep signal generation, data acquisition and digital filtering, processing, communications and executive control function and so on. And taking advantage of the semaphores, message queues and other mechanisms provided by the operating system, to achieve multi-task management and scheduling, and let multi-task module parallel operation come true.At last, the paper tests many parts of the performance of the detection system carefully, among them, test sensors and digital filtering of data processing are mainly done, by analyzing and comparing test errors, we assessed the final design of the system. The data results show that the electronic tag automatic detection system achieve a good design features, and device stability and reliability reach a relatively high indicator. In the actual production, the system operates stably and easily, feedbacks timely, which greatly improve production efficiency.