Active RFID Tag with Current-Sensing Cable Clamp
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Solution Overview
Problem
Wireless real-time location systems (RTLS) fail to determine whether tracked assets, such as medical devices and manufacturing equipment, are actively being used, leading to inefficiencies and frustration in locating available assets.
Innovation Solution
An active RFID tag with a current-sensing cable clamp that periodically monitors the AC current consumed by the asset, using magnetic sensors to estimate current usage and infer the device's usage state, and includes a tamper detection mechanism and battery charging capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If wireless RTLS tracks asset location only, then system simplicity is maintained, but asset usage status cannot be determined
Solution Approach 1:
The patent combines location tracking and usage status monitoring into a single RFID tag system. The tag simultaneously performs wireless communication for location tracking and current sensing for usage detection, eliminating the need for separate monitoring systems and reducing overall system complexity while providing comprehensive asset information.
Solution Approach 2:
The RFID tag is designed with multi-functionality, serving both as a location tracker and a usage status monitor. By integrating current sensing capabilities into the tag, it can determine whether an asset is actively being used while maintaining its primary location tracking function, making the system more versatile without requiring additional dedicated devices.
2Loss of information
If current monitoring is added to determine usage state, then asset usage information is obtained, but device complexity and power consumption increase
Solution Approach 1:
The system implements periodic current monitoring rather than continuous monitoring. The RFID tag samples the current at intervals to determine usage state, which reduces power consumption compared to continuous monitoring while still providing timely information about asset usage status for operational decision-making.
Solution Approach 2:
The RFID tag uses its own existing power supply to perform current sensing without requiring additional external power sources. The tag leverages its integrated circuitry to monitor current flow through the asset, enabling usage detection while maintaining power independence and avoiding the need for separate power infrastructure.
3Loss of information
If traditional RFID tags are used without current sensing, then system cost is lower, but asset usage status remains undetermined
Solution Approach 1:
The patent integrates current sensing functionality into the existing RFID tag structure by adding a current sensor and associated circuitry. This merging approach allows the tag to be manufactured as a unified component rather than assembling separate location tracking and current monitoring devices, simplifying the manufacturing process while enabling comprehensive asset monitoring.
Solution Approach 2:
The enhanced RFID tag is designed as a universal monitoring device that can track both location and usage status through current sensing. This multi-functional design allows a single tag type to serve multiple monitoring purposes across different asset types, reducing the need for specialized tags and simplifying inventory and deployment.
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 accurate determination of asset usage, reduces battery replacement needs, and enhances operational efficiency by providing real-time usage information and extended battery life through current monitoring and charging.
Implementation Method 1
the clamp assembly includes a plurality of magnetic field sensors configured to generate output signals based on current flow through the AC power cable
Implementation Method 2
a combiner circuit configured to combine the output signals from the magnetic field sensors to produce power to charge the rechargeable battery
Data Source
AI summary
Configurations are provided for measuring electrical current flow through an AC power cable to a host device. An enclosure is provided that includes various components, such as components of an active RFID tag. A cable clamp is provided that is configured to attach the enclosure to the AC power cable. The cable clamp includes magnetic sensors that are responsive to electrical current flowing through the AC cable to generate signals indicative of the current flowing through the AC cable.