RFID Incontinence Pad Detection Under Movement and RF Limits

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Solution Overview

Problem

Incontinence detection systems face challenges with patient movement causing signal interference, leading to weak communication between RFID tags and readers, which can result in false alarms and excessive RF exposure, while existing solutions either fail to reliably detect incontinence events or produce unnecessary alerts.

Innovation Solution

A system with a pad containing a passive RFID tag and an RFID reader subsystem using an array of spatially distributed antennas that vary energy transmission power and frequency, selecting different antenna pairs, power settings, and frequencies to ensure reliable communication and minimize RF exposure, thereby reducing false alarms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a more powerful signal is generated at the reader to overcome weak signals caused by patient movement, then signal strength is improved, but false wet indications increase and RF exposure exceeds safety limits

Engineering Contradiction:
Improvesignal strengthVSAvoidfalse wet indications
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the power level of the interrogation signal based on detected signal conditions. When the signal strength indicator indicates weak signal conditions, the reader automatically increases power to maintain reliable communication. When signal strength is adequate, the reader reduces power to minimize false detections and RF exposure. This dynamic adaptation resolves the contradiction by making signal strength reliable only when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the power parameter of the interrogation signal based on detected conditions. The reader monitors signal strength indicators and adjusts the power level parameter accordingly, transitioning between low and high power states to maintain reliable communication while avoiding false wet indications and excessive RF exposure.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a more powerful signal is generated at the reader to overcome weak signals caused by patient movement, then signal strength is improved, but RF exposure exceeds safety limits

Engineering Contradiction:
Improvesignal strengthVSAvoidRF exposure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the power level of the interrogation signal based on detected signal conditions. When the signal strength indicator indicates weak signal conditions, the reader automatically increases power to maintain reliable communication. When signal strength is adequate, the reader reduces power to minimize false detections and RF exposure. This dynamic adaptation resolves the contradiction by making signal strength reliable only when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the power parameter of the interrogation signal based on detected conditions. The reader monitors signal strength indicators and adjusts the power level parameter accordingly, transitioning between low and high power states to maintain reliable communication while avoiding false wet indications and excessive RF exposure.

Inventive Principle:
Principle #35Parameter changes

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 effectively detects incontinence events while minimizing false alarms and ensuring safe RF exposure levels, providing accurate and timely alerts to caregivers.

Implementation Method 1

an RFID reader subsystem having an array of two or more spatially distributed antennas, each member of the antenna array being adapted to radiate and receive electromagnetic energy

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

each member of the antenna array being adapted to radiate and receive electromagnetic energy

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3689240B1Incontinence detection system
Publication Date: 2023.09.06 HILL ROM SERVICES INC
  • EP3689240B1 patent drawingFigure 1~3
  • EP3689240B1 patent drawingFigure 2
  • EP3689240B1 patent drawingFigure 4

AI summary

A system for detecting an incontinence event includes a pad which is deployable on a mattress and which, as deployed, has an open circuit comprised of a first conductor extending from a first terminal of an RFID inlay, and a second conductor extending from a second terminal of the RFID inlay. The system also includes an RFID reader subsystem having an array of two or more spatially distributed antennas. The detection system commands spatially and temporally varying transmission of energy from the antenna array at a variety of powers and frequency settings. The detection system monitors the antenna array for a return signal resulting from the transmission. The return signal has a moisture status indicator which indicates whether or not liquid is present on the pad. The detection system also causes communication of a WET or DRY status to a destination. The reported WET or DRY status depends on the moisture status indicator.