Contactless CPU Card Presence Detection Without Disruption
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Solution Overview
Problem
Existing methods for detecting whether a contactless CPU card has left a radio frequency field cannot be performed in real time without disrupting the original operation status of the card, often requiring reactivation of the card seeking process.
Innovation Solution
A method involving a card reader that sends detecting instructions at regular intervals to determine if the card is within the radio frequency field, using specific instruction types and responses to set and reset flags, allowing for real-time monitoring without affecting the card's operation status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If card seeking operation is performed again to detect card presence, then detection can be performed, but original operation status of the card is disturbed
Solution Approach 1:
The patent extracts the detection function from the card seeking operation by introducing a separate detecting instruction (0xB2) that can independently determine card presence without triggering card seeking. This allows detection to be performed by sending a specific detecting instruction to the card, extracting the detection capability from the broader card seeking process and enabling it to operate independently.
Solution Approach 2:
The patent implements preliminary detection by sending detecting instructions at regular time intervals before actual data interaction is needed. This preliminary action allows the system to proactively determine card presence and notify the master computer in advance, rather than waiting until data interaction is required and then performing disruptive card seeking operations.
2Reliability
If real-time detection is implemented, then card presence can be monitored continuously, but system complexity increases
Solution Approach 1:
The card reader automatically sends detecting instructions at regular time intervals without requiring external intervention or complex scheduling systems. The detection process serves itself by using the existing communication infrastructure and simple timing mechanisms already present in the card reader, avoiding the need for additional complex real-time operating systems or sophisticated detection algorithms.
Solution Approach 2:
The patent implements real-time detection through periodic sending of detecting instructions at regular time intervals. This periodic action provides continuous monitoring capability while maintaining system simplicity, as the regular intervals can be easily managed by basic timing mechanisms rather than requiring complex continuous monitoring systems.
3Measurement precision
If card seeking is activated frequently, then detection accuracy improves, but data interaction efficiency decreases
Solution Approach 1:
The patent extracts the detection function from card seeking operations, allowing detection to be performed separately and more efficiently. By using detecting instructions that do not trigger card seeking, the system can achieve detection accuracy without the overhead and disruption of frequent card seeking operations, thereby maintaining data interaction efficiency.
Solution Approach 2:
Instead of performing complete card seeking operations for every detection need, the patent uses partial detection actions (sending detecting instructions) that achieve sufficient detection accuracy with less overhead. This partial action approach provides adequate detection capability while preserving data interaction efficiency by avoiding excessive full card seeking cycles.
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
Enables real-time detection of the card's presence or absence in the radio frequency field without disturbing the card's original operation, ensuring continuous data interaction and status monitoring.
Implementation Method 1
Contactless card is a new technology which is developed in recent years. The technology successfully combines radio frequency identification technology and IC card reader and writer together... data reading and writing operation is completed by transmission of radio wave
Data Source
AI summary
A method for detecting that a contactless CPU card leaves a radio-frequency field relates to the field of smart cards. The method comprises: receiving and judging whether a valid instruction sent by an upper computer is received, and conducting a corresponding operation according to the received instruction; as a notification card search instruction, conducting a card search operation, and judging whether returned information is received; obtaining card number information about a contactless card according to the returned information; as an APDU instruction, sending A data to the card in accordance with a designated format, judging whether a response is received, and sending the operation result to the upper computer; as an extension instruction, executing a corresponding operation, and sending the operation result to the upper computer; when a valid instruction is not received, judging the mark of the card in the radio-frequency field, and if the card is in the radio-frequency field, conducting a card detection operation, and sending the operation result to the upper computer; and if the card is not in the radio-frequency field, conducting a card search operation. The present invention can detect the problem that a CPU card leaves a radio-frequency field in real time.