Flexible Strain-Gauge Pressure Sensing Without Skin Contact

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Solution Overview

Problem

Existing wearable devices for measuring physiological parameters, such as heart rate and respiratory rate, are uncomfortable and sensitive to environmental factors like humidity, making them unsuitable for long-term, regular use.

Innovation Solution

A pressure sensor with high-sensitivity strain gauges integrated into furniture, such as chairs and mattresses, measures physiological parameters through temporary contact, using a deformable test body and computer processing to analyze signals from elemental gauges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wearable devices with skin-contact sensors are used to measure physiological parameters, then measurement precision is improved, but device comfort deteriorates and long-term usability is reduced

Engineering Contradiction:

Improvephysiological parameter measurementVSAvoiddevice comfort and usability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent introduces an intermediary medium (air gap or non-contact interface) between the sensor and the human body. Instead of direct skin contact, the sensor detects physiological signals through the air gap or by detecting body movement and pressure changes, thereby eliminating the discomfort of skin-contact sensors while maintaining measurement capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical skin-contact sensor systems with non-contact detection methods. Instead of using electrodes that touch the skin, the system uses optical, acoustic, or pressure-based detection to measure physiological parameters, eliminating the mechanical contact that causes discomfort

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If skin-contact sensors are used for physiological measurement, then measurement reliability is improved, but sensitivity to environmental factors like humidity increases

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidsensitivity to humidity and environmental factors

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The air gap or non-contact interface acts as a protective intermediary that isolates the sensor from direct exposure to humidity and environmental factors. This intermediary layer prevents moisture from reaching the sensor while still allowing physiological signal detection, thereby reducing environmental sensitivity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces humidity-sensitive electrical contact sensors with non-contact detection methods that are inherently less sensitive to environmental moisture. By using optical, acoustic, or pressure-based detection, the system eliminates the direct coupling between sensors and the humid environment that plagues traditional skin-contact devices

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If temporary contact sensor device is implemented, then user discomfort is reduced, but measurement duration is limited

Engineering Contradiction:

Improveuser discomfortVSAvoidmeasurement duration

Core Design Contradiction:

Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent enables continuous measurement by allowing the sensor to remain in permanent contact with the furniture or surface while the user occupies it. The non-contact or minimal-contact design eliminates the need to remove the device, enabling uninterrupted physiological monitoring throughout the entire usage period without user discomfort

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 sensor effectively measures heart rate, respiratory rate, and posture without direct skin contact, being less sensitive to environmental factors and providing continuous monitoring with minimal user discomfort.

Implementation Method 1

a pressure sensor comprising a deformable test body and a plurality of elemental gauges of high sensitivity linked to the test body and responsive to the deformation of the test body

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS20250268519A1Device and method for measurement of physiological parameters by temporary contact with a receptor surface

Publication Date: 2025.08.28 NANOMAD LAB

AI summary

The invention relates to a device and a method for evaluation of the physiological parameters of an individual in brief contact with said device, comprising: —a pressure sensor (121, 122) comprising a flexible test body (230) and elementary gauges (220) sensitive to the deformation of said test body; —a receptor surface (111, 112) able to come into contact with the individual and to transmit the forces resulting from this contact to the pressure sensor (121, 122); —computing means able to process the signals (520) coming from the pressure sensor, and a program implementing said computing means in such a way as to determine at least one item of information from among: —the breathing rate of the individual; —the heart rate of the individual; —the posture of the individual; —their development over time, and to generate an alert depending on these items of information.