Capacitance Measurement Segmentation for Tamper Detection
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Solution Overview
Problem
Existing tamper detection systems face challenges in accurately distinguishing valid capacitance measurements from those influenced by external electromagnetic disturbances, which can lead to inaccurate tampering attempts detection.
Innovation Solution
The system employs an integrated circuit that injects a current into a capacitor, divides the resulting voltage slope into segments, discards segments outside a predefined range, and uses segments within that range to determine capacitance, while utilizing a configurable capacitor array to reduce input impedance and counteract disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the integrated circuit measures capacitance directly without filtering, then the measurement process is simple and fast, but the measurement accuracy deteriorates due to electromagnetic disturbances
Solution Approach 1:
The voltage slope measurement is divided into multiple slope segments, each representing a specific time interval. The integrated circuit evaluates each segment independently to determine if it falls within a valid range, allowing the system to filter out distorted measurements while maintaining a relatively simple overall architecture.
Solution Approach 2:
The system performs preliminary evaluation of slope segments before final capacitance calculation. By pre-defining valid slope ranges and evaluating segments against these criteria, the system filters out invalid measurements early in the process, preventing erroneous data from affecting the final result.
2Reliability
If the system accepts all voltage slope measurements, then the detection process is fast, but the reliability deteriorates due to inclusion of invalid measurements from electromagnetic interference
Solution Approach 1:
The measurement process is segmented into multiple evaluable portions, where each slope segment can be independently validated. This allows the system to quickly identify and discard invalid segments while processing only the necessary valid portions, maintaining efficiency while improving reliability.
Solution Approach 2:
The system performs measurements over multiple time intervals (slope segments) rather than a single measurement. By taking more measurements than strictly necessary and filtering them, the system ensures that at least some valid measurements are obtained even in the presence of electromagnetic interference.
3Adaptability or versatility
If the integrated circuit uses a fixed measurement approach, then the device complexity is low, but the adaptability deteriorates when facing varying electromagnetic disturbance conditions
Solution Approach 1:
The system dynamically evaluates each slope segment against predefined valid ranges and can adapt its measurement strategy based on the characteristics of each segment. This allows the measurement process to respond to varying electromagnetic conditions without requiring complex real-time adjustment mechanisms.
Solution Approach 2:
The system changes the measurement parameters by dividing the voltage slope into multiple segments with different time intervals. By adjusting how the measurement is partitioned and evaluated, the system adapts to different electromagnetic disturbance conditions while maintaining a relatively simple device architecture.
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
This approach enhances the robustness and accuracy of capacitance measurements, effectively distinguishing valid from invalid results and reducing the impact of electromagnetic interference, thereby improving the reliability of tampering detection.
Implementation Method 1
an integrated circuit configured to inject a current in said capacitor and to detect a corresponding voltage slope on said capacitor
Data Source
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AI summary
In accordance with a first aspect of the present disclosure, a system for detecting tampering with a product is provided, the system comprising: a capacitor comprised in or attached to the product; an integrated circuit configured to inject a current in said capacitor and to detect a corresponding voltage slope on said capacitor; wherein the integrated circuit is further configured to divide said voltage slope into a plurality of slope segments; wherein the integrated circuit is further configured to discard a first set of slope segments, whose slope value falls outside a predefined range of slope values; wherein the integrated circuit is further configured to use a second set of slope segments, whose slope value falls within said predefined range, for determining a capacitance on the capacitor. In accordance with a second aspect of the present disclosure, a corresponding method for detecting tampering with a product is conceived. In accordance with a third aspect of the present disclosure, a corresponding computer program is provided.