Resonance Magnetic Field Generator for Skimming Prevention
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Solution Overview
Problem
Conventional magnetic field generators used in card readers to prevent skimming have temporary and weak disturbing magnetic fields due to power supply by a transistor with switching function, making them ineffective in continuously disrupting skimming magnetic heads.
Innovation Solution
A magnetic field generator with a resonance part consisting of an inductor and capacitor, where AC current flows to generate a magnetic field, and a current direction monitoring section controls the timing for charging, ensuring a continuous and strong disturbing magnetic field is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a transistor switching circuit is used to power the coil, then the device complexity is reduced, but the duration of magnetic field generation becomes short and the magnetic field strength becomes weak
Solution Approach 1:
The patent applies periodic action by using a transistor switching circuit to periodically charge and discharge the capacitor, which in turn periodically generates magnetic fields through the coil. This creates a continuous series of magnetic field pulses rather than a single temporary field, effectively extending the duration of magnetic field generation while maintaining circuit simplicity
Solution Approach 2:
The patent applies preliminary action by charging the capacitor in advance before magnetic field generation is needed. The pre-charged capacitor then rapidly discharges through the coil when triggered, producing a strong and sustained magnetic field pulse. This preliminary charging phase allows the system to generate strong magnetic fields on demand without requiring continuous high-power supply
2Ease of operation
If a transistor switching circuit is used to power the coil, then the ease of operation is improved, but the magnetic field strength becomes weak
Solution Approach 1:
The periodic switching of the transistor creates repeated magnetic field pulses that accumulate their effect over time. Each pulse contributes to the overall magnetic field exposure, effectively increasing the total magnetic field strength delivered to the skimming head while keeping the control mechanism simple
Solution Approach 2:
By pre-charging the capacitor to a high voltage level, the system stores significant energy that is then released in a controlled pulse through the coil. This preliminary energy storage enables the generation of strong magnetic fields without requiring complex high-power continuous supply circuits
3Loss of energy
If temporary magnetic field generation is used, then the loss of energy is reduced, but the reliability of preventing skimming decreases
Solution Approach 1:
The periodic magnetic field generation creates multiple disruption opportunities for any skimming attempt. Even if one pulse is missed or insufficient, subsequent pulses continue to disrupt the skimming process, significantly improving reliability while maintaining low energy consumption through the use of a simple capacitor discharge mechanism
Solution Approach 2:
The pre-charged capacitor serves as a ready energy reservoir that can be rapidly deployed when skimming detection occurs. This allows the system to maintain low standby energy consumption while being capable of delivering strong, reliable magnetic field pulses when needed, thus achieving both energy efficiency and high reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables continuous and efficient generation of a disturbing magnetic field, effectively preventing illegal data acquisition by skimming magnetic heads with improved accuracy and reliability.
Implementation Method 1
a resonance part in which an inductor and a capacitor are connected with each other and which is structured so that an AC current is flowed between the inductor and the capacitor by charging electric charge to the capacitor and discharging the electric charge to generate a magnetic field by a resonance
Data Source
AI summary
A magnetic field generator may include a magnetic field generation part including a resonance part including an inductor and a capacitor connected with each other, and which is structured so that an AC current is flowed between the inductor and the capacitor by charging electric charge to the capacitor and discharging the electric charge to generate a magnetic field by a resonance; a current direction monitoring section structured to monitor a direction of a current flowing through the inductor of the magnetic field generation part; and a judging section structured to control a timing for charging in the magnetic field generation part depending on the direction of the current flowing through the inductor which is obtained by monitoring of the current direction monitoring section.