RFID Tag Weight Detection via Piezoelectric Material
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Solution Overview
Problem
Conventional RFID systems are ineffective in tracking and managing the movement of inventory items, particularly in large-scale warehouses, as they fail to detect errors remotely and struggle with reading tags on non-friendly materials like metal and liquid items, and cannot detect shrinkage or changes in the number of items in a sealed package.
Innovation Solution
A modified RFID tag system that incorporates a piezoelectric material as a weight sensor, which generates an electric current proportional to the mechanical stress, allowing the tag to detect changes in weight and transmit this information to a reader, enabling real-time monitoring of package contents and detecting tampering or shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RFID tags are used on non-friendly materials like metal and liquid items, then the tags cannot be read successfully, but adding special handling or alternative materials increases device complexity and cost
Solution Approach 1:
The patent introduces an intermediary reader device that acts as a mediator between the RFID tag and the conventional RFID system. This reader includes a processor that can generate alternative interrogation signals (such as acoustic waves, light, or other non-RF signals) when RF signals fail to successfully communicate with tags on non-friendly materials. The reader translates between different signal types, enabling successful tag reading without requiring changes to the tags themselves or the underlying RFID protocol standards.
2Loss of information
If fixed RFID interrogators are positioned at loading dock gates to track items, then arrival tracking is achieved, but errors remote to these locations cannot be detected and the system is not cost effective
Solution Approach 1:
The patent enables inventory items to self-report their location and status through mobile computing devices carried by warehouse operators. Instead of requiring fixed interrogators at every location, the system allows operators to actively scan and record item information as they move through the warehouse. This self-service approach distributes the tracking function across multiple mobile points rather than requiring centralized fixed infrastructure, reducing overall system complexity while improving error detection coverage.
Solution Approach 2:
The system transitions from static fixed interrogators to dynamic mobile scanning capabilities. Operators move through the warehouse with portable readers, allowing real-time detection of items at their actual locations rather than relying on items passing predetermined fixed points. This dynamic approach improves error detection by enabling checks at pick-up locations, staging areas, and other remote positions throughout the warehouse operation.
3Loss of information
If conventional RFID systems are used in large-scale warehouses, then inventory records can be maintained, but movement management and error detection are ineffective
Solution Approach 1:
The patent implements a feedback mechanism where the mobile computing device and system processor continuously compare expected item locations (from pick lists, staging orders, or routing information) with actual scanned locations. When discrepancies are detected, the system provides immediate feedback to the operator through the mobile device, allowing real-time correction of errors such as picking wrong items or placing items at incorrect locations. This closed-loop feedback system significantly improves movement tracking accuracy and operational efficiency.
Solution Approach 2:
The system performs preliminary validation checks before items are finalized in their destination locations. The mobile reader can verify item identities, check against required pick lists, and confirm proper placement before the operation is completed. This preliminary action prevents errors from propagating through the system and reduces the need for later corrections, thereby improving overall warehouse productivity.
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 system allows for accurate tracking and monitoring of inventory items, including those on non-friendly materials, and dynamically detects changes in package contents, enhancing warehouse efficiency and reducing errors and shrinkage.
Implementation Method 1
the sensor comprises a piezoelectric material that generates an electric current in response to a change in weight of the package material
Data Source
AI summary
The present invention is a method system that detects the altering of the contents of a package. This system comprises a Radio Frequency Identification (RFID) tag that is affixed to a package. This RFID can receive, store and transmit information received related to the package contents. A pressure sensitive material is positioned in the package such that this material can sense the weight of the package contents. When the weight of the package contents changes, the RFID tag will receive a signal directly or indirectly from the pressure sensitive material. This weight change is recorded in the RFID. When a RFID reader energizes the RFID, this current package weight is transmitted to the RFID tag reader. The RFID tag reader can then determine if the weight transmitted by the RFID tag is the original package weight or a new package weight. A new package weight would indicate some altering of the original package contents.