Advanced metal detection system based on TMR sensor array

The presence of unexpected metal fragments is of major concern to some manufacturing lines, such as foodstuff and pharmaceutical products. Conventional coil metal detectors only have capability of detecting, which cannot localize metal pieces precisely. This paper presents an advanced metal detection system based on tunneling magnetoresistance (TMR) sensors array. To achieve the function of metal localization, the system is designed to contain 16 TMR sensors. Meanwhile, considering the electromagnetic interference (EMI) from manufacturing environment, the system is also integrated with matched filtering technique, which can eliminate EMI greatly. Experimental results demonstrate that such novel metal detection system can sense the metal particle with 1-mm diameter as the belt running in regular speed. Moreover, it can localize the metal particle with the spatial resolution of 3 cm.