Capacitive Sensor Sheet for Bedridden Person Detection

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Solution Overview

Problem

Current methods for monitoring the activity and falls of bedridden individuals in healthcare settings are inadequate due to the lack of personnel, high costs of video surveillance, and the limitations of existing sensors that are not comfortable, easy to maintain, or compatible with pressure ulcer prevention measures.

Innovation Solution

A system comprising a capacitive sensor-equipped fitted sheet with a processing unit that alerts caregivers to changes in a bedridden person's position or absence, designed to be comfortable, washable, and compatible with pressure ulcer prevention measures, using sensors integrated into the sheet that are not directly perceivable to the individual.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If video surveillance system is installed to monitor bedridden individuals, then fall detection capability is improved, but system cost and complexity increase significantly

Engineering Contradiction:
Improvefall detection capabilityVSAvoidsystem cost and complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/video surveillance system with a capacitive sensing system that uses electrical fields to detect presence and movement. The capacitive sensors embedded in the mattress foundation detect changes in capacitance caused by the body's proximity or contact, eliminating the need for complex video cameras, processors, and storage systems while maintaining reliable fall and absence detection capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs inexpensive capacitive sensors that can be easily manufactured and integrated into the mattress foundation. These sensors are significantly cheaper than video surveillance equipment and can be replaced or reconfigured if needed, providing a cost-effective solution for continuous monitoring without the high capital investment required for video systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If capacitive sensors are integrated directly into the mattress layer, then sensor functionality is improved, but manufacturing complexity and maintenance difficulty increase

Engineering Contradiction:
Improvesensor functionalityVSAvoidmanufacturing and maintenance simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the sensor system into modular capacitive sensing elements that are distributed across the mattress foundation. Each sensor can be independently manufactured and tested before integration, simplifying the manufacturing process. The segmented design also allows individual sensors to be replaced or repaired without affecting the entire mattress system, improving maintainability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs the capacitive sensors to serve multiple functions: detecting presence, detecting movement, determining position, and identifying falls. This multi-functionality is achieved through a single sensor type and processing approach, eliminating the need for different sensor types for different functions and thereby simplifying manufacturing and maintenance compared to specialized sensor systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If physical restraint methods are used to prevent falls, then fall prevention effectiveness is improved, but patient comfort and caregiver psychology deteriorate

Engineering Contradiction:
Improvefall prevention effectivenessVSAvoidpatient comfort and caregiver psychology
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent enables the monitoring system to operate autonomously without requiring physical restraint of the patient. The capacitive sensors continuously detect the patient's presence and movements, automatically triggering alerts when falls or abnormal movements occur. This self-monitoring approach eliminates the need for restrictive physical restraints, thereby maintaining patient comfort and avoiding the psychological burden on caregivers associated with restraint use.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical physical restraint systems with an electrical sensing and alerting system. Instead of using vests, straps, or bed rails to physically restrict movement, the system uses capacitive sensors to detect and report falls and abnormal movements, thereby preventing falls through awareness and rapid response rather than through physical constraint.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If staff increase monitoring time and attention, then detection accuracy is improved, but labor costs and operational complexity increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidstaff time and resources
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent implements a self-monitoring system where the capacitive sensors automatically and continuously detect presence, movement, and falls without requiring staff attention. The system processes sensor data in real-time and generates alerts autonomously, providing high detection accuracy while eliminating the need for increased staff monitoring time and resources.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent enables continuous monitoring through the capacitive sensor system that operates 24/7 without interruption or fatigue. Unlike human staff who require breaks and rotation, the electronic sensing system maintains constant surveillance, improving detection accuracy while avoiding the increasing labor costs associated with extended staff monitoring hours.

Inventive Principle:
Principle #20Continuity of useful action

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 monitors bedridden individuals, issues alerts for changes in position or absence, maintains comfort and prevents pressure ulcers, and is easy to maintain and use, reducing the need for extensive personnel and minimizing costs.

Implementation Method 1

A system is proposed comprising a capacitive sensor-equipped fitted sheet with a processing unit that alerts caregivers to changes in a bedridden person's position or absence

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3769676B1System and method for detecting the presence of bedridden persons
Publication Date: 2022.02.16 WINNCARE FRANCE
  • EP3769676B1 patent drawingFigure 1
  • EP3769676B1 patent drawingFigure 2
  • EP3769676B1 patent drawingFigure 3

AI summary

System (3) for tracking a bedridden person comprising a sheet (4) suitable for covering a mattress (2) of a bed (1), capacitive sensors (5) arranged transversely on the sheet, the sensors being suitable for measuring an active length (L) corresponding to a sensor length covered by the bedridden person, a processing unit (6) configured to collect and analyze the active sensor lengths, one sensor being attached to the sheet.