RFID Tag Reception Parameter Frozen State Detection
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Solution Overview
Problem
Refrigerated delivery receptacles are expensive and pose maintenance challenges, and existing RFID tags with temperature sensors are costly, making it difficult to monitor the frozen state of items effectively.
Innovation Solution
A control circuit determines the frozen state of an object using an RFID tag's reception parameter, such as received signal strength, without explicit temperature data, allowing for reliable and inexpensive monitoring of ice packs in delivery containers, and potentially triggering alerts for unwanted warming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigeration components are used in delivery receptacles, then the risk of items warming is reduced, but the cost and maintenance challenges increase
Solution Approach 1:
The patent replaces mechanical refrigeration systems with an RFID-based detection system. Instead of using active cooling mechanisms, the invention uses radio frequency signals to detect the frozen state of items by measuring signal strength variations caused by water content changes during phase transition.
Solution Approach 2:
The patent introduces RFID tags as intermediary elements between the detection system and the items. These tags attach to items and provide indirect information about their frozen state through signal strength measurements, eliminating the need for direct temperature sensing or refrigeration components.
2Measurement precision
If RFID tags with integral temperature sensors are used, then temperature readings can be obtained, but the cost increases
Solution Approach 1:
The patent creates a functional copy of temperature sensing capability using RFID signal strength measurements. Instead of using actual temperature sensors, the system infers temperature-related information (frozen state) from the interaction between RFID radio waves and the dielectric properties of water in the item.
Solution Approach 2:
The patent employs inexpensive RFID tags without temperature sensors, sacrificing the need for expensive sensing components. The system accepts that these simpler tags provide indirect measurements through signal strength, which is sufficient for determining frozen state when combined with calibration data.
3Ease of manufacture
If simple RFID tags without temperature sensors are used, then cost is reduced, but the ability to determine frozen state becomes more difficult
Solution Approach 1:
The patent changes the measurement parameter from direct temperature sensing to RFID signal strength measurement. By measuring how the dielectric properties of water affect radio frequency signal propagation, the system indirectly determines the frozen state of items using simple, inexpensive RFID tags.
Solution Approach 2:
The patent implements a calibration process where the RFID system measures signal strength at known temperatures to establish reference data. This feedback mechanism allows the system to interpret signal strength measurements in terms of frozen state, compensating for the lack of direct temperature sensing capability.
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 method enables cost-effective monitoring of the frozen state of items in delivery containers, reducing the risk of items warming to an unwanted level, and can be implemented using simple, inexpensive RFID tags without temperature sensors.
Implementation Method 1
the received signal strength for transmissions from RFID tags can vary based on the dielectric properties of an object to which the RFID tags are attached
Implementation Method 2
an increasing amount of liquid will absorb a corresponding increasing amount of radio-frequency energy
Data Source
AI summary
A control circuit determines a reception parameter for an RFID tag that is attached to an object (such as an ice pack) and then determines a frozen state of the object as a function of that reception parameter. By one approach the RFID tag provides a transmission to support the aforementioned determinations, which transmission provides no data that explicitly represents temperature. The reception parameter can comprise, for example, an indication of received signal strength. So configured, a relatively higher indication of received signal strength can serve to determine that the object is and/or remains at least substantially frozen while a relatively lower indication of received signal strength can serve to determine that the object is not at least substantially frozen.