The Brief Introduction of Security Metal Detector
In order to accurately determine the location of metal objects hiding, you need X-ray security detecting system with high detection accuracy. Using high sensitivity Hall element as a linear sensor, the sensor due to changes in the magnetic field around the metal appears due to the detection coil improving the detection precision processing components using AT89S52 micro controller as the control, the test results are analyzed to determine for the mail, baggage, parcels and human entrained harmful metal objects ( knives, Firearms, weapons components, ammunition and explosives, metal packaging, etc. ) is detected, and can be used for customs, airports, railway stations, security checks dock can also be used to detect hidden in the walls, the inner wall panels, Voids and soil above items and other metal objects.
An X-ray security inspection system design based on electromagnetic theory, when a metal object is placed in a magnetic field changes, the metal conductor will have self-closing induction current, which is the eddy current effect of the metal.
To generate additional vortex magnetic field in the opposite direction to the outer, the weakening of the external magnetic field you should know the introduction of x-ray bag scan device need to have changes. Accordingly, access to an AC sinusoidal signal around the skeleton empty the core coil, the current flowing through the coil generates an alternating magnetic field around the coil when the metal is close to the vortex generated by the magnetic field acting metal weakens the magnetic coil changes. Conductivity of metals rate of security metal detector, the greater the frequency of the alternating current, the greater the eddy current intensity with the magnetic field of the original and the stronger the inhibition. Therefore, when a metal object near the plane of the coil is energized, both the dielectric permeability of the variable or eddy effects of metals can cause changes in the magnetic induction.
Entire detection system AT89S52 of security metal detectors as the control, the hardware circuit is divided into two parts, as part of the coil oscillation circuit comprising: circuit, amplifier circuit, and the detection coil; another part control circuit comprising: UGN3503 type Hall sensor current, the preamplifier circuit, the peak power detector road, ADC0809 ADC, AT89S52 microcontroller, LED display circuit, sound the alarm circuit and power supply circuit.
Points remain independent, isolated interaction between static levels, so that the circuit will not be much overall drift.
All in all the X-ray security baggage scanner with operating frequency, obtains the sensitivity and stability of the main technical means of the instrument labeled, and detection sensitivity of the security metal detector on the size of the coil, i. e. large size detection area, the lower center of the coil the magnetic field strength, the higher the magnetic field strength near the vicinity of the coil winding, the Hall element solid set at the center of the coil, the magnetic flux in order to ensure, through its size should not be too much on the detection coil, the specific size determined by experiment. For the design of security metal detectors, you can be at airports, major sporting events (Such as the Olympics ), exhibitions safety testing to troubleshoot luggage, parcels and human entrained knives, firearms, ammunition and other harmful contraband metal objects ; industrial sector ( including watches, glasses, Gold and silver jewelry, electronics and other products containing metal products factory ) You can also use a security metal detector to detect access to personnel, to prevent the loss of precious metal materials ; exams can also s use security metal detector to prevent the use of mobile phones and other tools for candidates to cheat, has a good range of applications.