Research on Stealthy Headphone Detector Based on Geomagnetic Sensor

Ya Liu,Zhihui Luo,Si Chen,Liqing Pan

doi:10.1051/matecconf/20166102015

Abstract

A kind of stealth headphone detector based on geomagnetic sensor has been developed to deal with the stealth headphones which are small, extremely stealthy and hard to detect. The U.S. PNI geomagnetic sensor is chosen to obtain magnetic field considering the strong magnetic performance of stealth headphones. The earth’s magnetic field at the geomagnetic sensor is eliminated by difference between two geomagnetic sensors, and then weak variations of magnetic field is detected. STM8S103K2 is chosen as the central controlling chip, which is connected to LED, buzzer and LCD 1602. As shown by the experimental results, the probe is not liable to damage by the magnetic field and the developed device has high sensitivity, low False Positive Rate (FAR) and satisfactory reliability.

Highlights

Stealthy headphone is used as a common tool for cheating and illegal monitoring at present and has brought great trouble to the inspection work
The rare earth type is mainly composed of ndfeb magnets, and the vibrations coming from the audio frequency magnetic field enable the wearer to hear sounds
Because the volume of the stealthy headset which can be stuffed into the external auditory canal directly is smaller and smaller, it is hard for the inspector to find the rice type stealthy headset through visual method

Summary

Introduction

Stealthy headphone is used as a common tool for cheating and illegal monitoring at present and has brought great trouble to the inspection work. Metal detectors which are sensitive to metal materials with certain volume are easy to lead misinformation when influenced by irrelevant metal, such as belt buckle, key, hairpin and zipper, which are always on the object to be inspected. It is hard for the metal detector to detect the tiny devices, let alone the rice granular stealthy headphone[5]. The device can effectively detect changes of the magnetic field and eliminate the magnetic field interference. The side previously grounded is charged or discharged while the other is grounded

Experiment and Discussion

Conclusions