RFID Pressure Sensing via RSSI in Enclosed Electromagnetic Fields
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Solution Overview
Problem
Current RFID technologies face challenges in tracking and managing small items like pills or grains, where attaching individual RFID sensors is impractical, and in sensing material levels or pressures in various environments, due to limitations in signal strength and interference.
Innovation Solution
The development of RFID-enabled systems and dispensers that use electromagnetic fields and sensors within enclosures or waveguides to transmit and measure signal strength indications (RSSI), allowing for the tracking of items and determination of influences such as material levels or pressures without direct sensor attachment, through a system comprising an interrogator, processor, and RFID field sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual RFID sensors are attached to track small items, then tracking capability is improved, but practicality deteriorates due to the impracticality of attaching sensors to each item
Solution Approach 1:
The system divides the enclosure into multiple zones with distributed RFID field sensors positioned at different locations. Each sensor monitors its local zone independently, allowing the system to track items without requiring individual sensors on each item. The segmentation of monitoring responsibilities across multiple fixed sensors resolves the contradiction between tracking precision and attachment practicality.
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the RFID sensors and the items being tracked. Instead of direct sensor-item contact, the electromagnetic field mediates the interaction, allowing sensors to detect items wirelessly through the field's response to item presence. This intermediary approach eliminates the need for physical sensor attachment while maintaining tracking capability.
2Measurement precision
If RFID sensors are used to sense material levels or pressures, then sensing capability is improved, but signal strength deteriorates due to limitations in electromagnetic field penetration and interference
Solution Approach 1:
The system positions RFID field sensors at specific locations within the enclosure where electromagnetic field strength is optimized for the sensing application. Sensors are strategically placed to maximize their ability to detect material levels or pressures while minimizing signal loss. This local optimization of sensor positioning resolves the contradiction between sensing capability and signal strength.
Solution Approach 2:
The patent combines multiple RFID field sensors into a coordinated network that collectively monitors the enclosure environment. By merging the capabilities of multiple sensors and coordinating their measurements, the system achieves reliable material level and pressure sensing despite individual signal strength limitations. The combined data from multiple sensors compensates for weak individual signals.
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 monitoring of small items and material levels or pressures with high resolution, even in environments where direct sensor attachment is impractical, by analyzing reflected signal strength indications to determine the presence and quantity of items or changes in material conditions.
Implementation Method 1
The interrogator is configured to transmit an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure
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 RFID 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.