Research And Implementation Of Very Low Frequency Metal Detector

Metal detectors are originally applied to detections of mine and metal under the ground.Nowadays, it can be also used to protective and safe detections, such as travel security check,food, metallurgy, anti-terrorist and medicines. As the enhancement of people life consumptionrequirements, users put forward higher request for the performance of metal detectors. Butthe key is that how to realize the metal detector with more advanced performance.On the basis of overseas and domestic research status,this paper mainly discusses thathow to discovery the metal for metal detectors, and that how to discriminate the type of metalunder the ground. Too much emphasis is put on the electromagnetic detection of metal targets,coils, the interference of background signals and mineralization, detection depth, and theability of discriminating types of metal.The basis theory on metal detectors mainly include: electromagnetic induction and eddytheory, coils configuration and the basic circuit component units and corresponding functions.Detection depth means the effective distance between coils and targets, namely limitdistance.It can be affected by many factors.These factors will be studied so that detectiondepth is much further, which provides us more convenience. The ability of discriminatingtypes of metal means types of metal targets can be told when being discovered. Higher thediscrimination rate is, better our needs are satisfied. The part on discrimination rate includestheoretical basis and the discrimination algorithm. Because a metal detector is a kind ofequipment for outdoor use, it can be impacted by the mineralization. Then, The detectiondepth and discrimination rate could be directly affected by the mineralization. Accordingly, itis significant to research and analyse mineralization. Besides, the analysis of backgroundsignals has the same importance as the mineralization. because both earth signals andtemperature drift will be affected by background signals. And, the interference frombackground signals need to be eliminated.At last, the software design and simulation can be introduced. Then there are tests andanalysis of experiment results.