Abstract: A metal detector is an instrument that used to detect and probe metals. Here a type of induction balance metal detectors is designed. The metal detector works on very low frequency generates a magnetic field probe, after which the detected metal targets would also generate a magnetic field because of the eddy current effect. By probing this return magnetic field, the signal will be extracted and deal with via the internal circuit of the metal detector. A communication protocol of low-energy Bluetooth is designed to ensure steady data transmission between the mobile terminals and the metal detectors. The mobile terminal will further process the received signal using machine learning algorithms to achieve the purpose of distinguishing different metals.

Key words: metal detector, low-energy Bluetooth, eddy current effect, communication protocol

摘要： 金属探测器是用来检测和探测金属的仪器，这里所设计的是感应平衡式金属探测器的一种。感应平衡式金属探测器首先发射探测电磁场，检测到的金属目标由于涡流效应会返回一个电磁场信号，对该信号进行提取，通过金属探测器内部电路对探测信号进行处理与分解，达到区分信号的要求。通过低功耗蓝牙连接移动终端和金属探测器，其中设计了一套通信协议实现金属探测器和移动终端之间的稳定数据传输，接着在移动终端设备上使用机器学习算法对接收信号作进一步的处理和区分，达到精确区分不同种类金属的目的。

关键词: 金属探测器, 低功耗蓝牙, 涡流效应, 通信协议