RFID-Enabled Dispenser Fill-Level Sensing Using RSSI
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Solution Overview
Problem
Current RFID systems face challenges in tracking small items like pills or grains due to impracticality of attaching individual RFID sensors and in managing inventory levels in enclosures, where traditional sensors are not effective.
Innovation Solution
The implementation of RFID-enabled dispensers and sensors within enclosures that use electromagnetic fields and distributed RFID sensors to track items and determine influences, such as fill levels, through reflected signal strength indications (RSSI) measured by interrogators and processed for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual RFID sensors are attached to each small item for tracking, then tracking precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
Instead of attaching physical RFID sensors to each item, the patent uses RFID tags embedded in the dispenser structure that are activated by the presence of items. The system creates a virtual representation of item presence through RFID field detection rather than physical tag attachment, reducing complexity while maintaining tracking precision
Solution Approach 2:
The patent replaces the mechanical approach of attaching individual sensors to each item with an electromagnetic field-based RFID detection system. The RFID field naturally extends through space and can detect items without physical contact or attachment, simplifying the system architecture
2Measurement precision
If traditional sensors are used to manage inventory levels in enclosures, then implementation is simple, but measurement precision and reliability are insufficient
Solution Approach 1:
The RFID system serves multiple functions simultaneously: it tracks individual items, monitors inventory levels, detects item presence/absence, and provides location information within the enclosure. This multi-functionality achieves high measurement precision without proportionally increasing system complexity
Solution Approach 2:
The patent introduces RFID fields as an intermediary between the detection system and items. The electromagnetic field penetrates the enclosure and interacts with RFID tags on items, providing indirect but precise measurement of item presence and location without requiring direct physical sensors on each item
3Measurement precision
If RFID tags are attached to each small item like pills or grains, then tracking accuracy is improved, but ease of manufacture and deployment deteriorates
Solution Approach 1:
Instead of placing RFID tags on items and reading them, the patent inverts the approach by placing RFID reader elements in the dispenser structure and detecting the passive RFID fields emitted by or reflected from items. This inversion eliminates the need for manual tag attachment to each item while maintaining tracking accuracy
Solution Approach 2:
The system uses the items' own RFID tags (or inherent electromagnetic properties) to generate the detection signal. The items essentially serve themselves by their presence in the RFID field, eliminating the need for external active sensors on each item and simplifying 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 tracking and management of small items and inventory levels without the need for individual RFID tags on each item, providing fine resolution and moderate to very fine resolution tracking capabilities.
Implementation Method 1
An antenna, coupled to the waveguide, is configured to generate an electromagnetic field within the waveguide in response to an incident signal sent from an interrogator
Implementation Method 2
One or more of the RFID sensors respond to the electromagnetic field by transmitting, via the collector, a reflected signal to the interrogator, the reflected signals containing the individual identifications of the responding RFID sensors
Implementation Method 3
The interrogator is configured to receive the reflected signals, measure one or more returned signal strength indications ('RSSI') of the reflected signals and send the RSSI measurements and the corresponding identification of the responding REID sensors as information to the processor
Data Source
AI summary
Methods, apparatuses and systems for radio frequency identification (RFID)-enabled information collection are disclosed, including an enclosure, a collector coupled to the enclosure, an interrogator, a processor, and one or more RFID field sensors, each having an individual identification, disposed within the enclosure. In operation, the interrogator transmits an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure. The electromagnetic field is affected by one or more influences. RFID sensors respond to the electromagnetic field by transmitting reflected signals containing the individual identifications of the responding RFID sensors to the interrogator. The interrogator receives the reflected signals, measures one or more returned signal strength indications (“RSSI”) of the reflected signals and sends the RSSI measurements and identification of the responding RFID sensors to the processor to determine one or more facts about the influences. Other embodiments are also described.