Research On Metal Label Detection Based On Eddy Current Technology

The continuous development of Internet technology and Internet information industry promoting goods classification,automatic recognition and a series of intelligent operation,so it is more and more important.In the existing recognition technology,there are certain restrictions on the application of scene.Therefore,in order to meet the needs of high-speed development of the Internet of things,the new detection method and identified equipment is also becoming more and more important.In these devices,the research and development of the equipment with the information recording mode by the metal label receives the widespread attention of the researchers and the electronic manufacturer.So,it is more important to study the detection and recognition of the symbol information of metal labels.This design is a metal label detector based on eddy current technology research,including the rational design of the probe,the signal conditioning circuit and embedded system,the detection and recognition of metal symbols,the system has a good recognition effect,low error rate,suitable for small type.This paper starting from the basic principle,explaining the basic principle of eddy current testing,analysis of the impedance model and factor.Then,analyzed the characteristics of the impedance,the range of eddy current effect,the resolutions of the metal label based on the impedance model,for the automatic gain control algorithm is also introduced in detail.We design the hardware circuit based on the basic principle of eddy current.First of all,we design the metal label probe and give a suitable probe based on impedance factors.Second,the analog signal experiences a series of operations,including amplification,phase detection,changing the metal label into the voltage signal,signal zero,voltage controlled gain amplifier,bias voltage superposition and filtering.In the circuit design,we design the printed circuit board(PCB)design using Altium Designer software,and debug the circuit with the digital storage oscilloscopes(DSO).According to the actual situation,we encode of metal labels and identify the symbols according to the encoding rules and actual data,the recognition algorithm is simulated by using Matlab,finally,we implement recognition algorithm in the embedded processor with C language,and the recognition results will be output to the liquid crystal display(LCD)display and serial port.In the case of hardware circuit,recognition algorithm and software design.