Multi-Sensor Sweat Patch for Continuous Volume Tracking

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Solution Overview

Problem

Existing sweat monitoring devices fail to accurately track the volume of sweat generated by a living organism and do not allow for continuous monitoring beyond the initial saturation point of the absorption element.

Innovation Solution

A device with multiple sensors, each having distinct absorption capacities, measures electrical impedance to determine ionic concentration and volume of sweat, allowing for precise tracking of sweat volume and extending the measurement range by utilizing overlapping sensor saturation points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single sensor with fixed absorption capacity is used, then the device structure is simple, but the measurement range is limited and cannot track sweat volume beyond saturation point

Engineering Contradiction:
Improvesweat volume tracking accuracyVSAvoidsensor array configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement function is segmented across multiple sensors, each with distinct absorption capacities. The first sensor captures initial sweat volume until saturation, while the second sensor continues monitoring beyond that point. This segmentation allows the system to track sweat volume across the entire range without requiring a single complex sensor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensors are designed with different absorption capacities as a key parameter variation. By changing the absorption capacity parameter among sensors, the system creates a staged measurement approach where each sensor operates optimally within its capacity range, extending the overall measurement capability.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If multiple sensors with distinct absorption capacities are used, then the measurement range is extended, but the device complexity increases

Engineering Contradiction:
Improvecontinuous monitoring durationVSAvoidmulti-sensor system architecture
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The monitoring duration is segmented across sensors with different absorption capacities. The first sensor monitors until saturation, then the second sensor takes over for continued monitoring. This temporal segmentation extends the total monitoring duration without requiring one sensor to operate indefinitely at reduced accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system ensures continuous useful action by designing sensors whose absorption capacities overlap. When the first sensor saturates, the second sensor is already partially filled and continues monitoring without interruption, maintaining continuous sweat volume tracking throughout the extended duration.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If sensors with overlapping saturation points are used, then sweat volume tracking accuracy is improved, but the processing complexity increases

Engineering Contradiction:
Improvesweat concentration measurement accuracyVSAvoiddata processing algorithm
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The processing unit uses feedback from electrical impedance measurements to determine both sweat volume and concentration. By continuously monitoring impedance changes in each sensor and comparing them against known absorption capacities, the system calculates accurate sweat parameters through iterative feedback processing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system exploits parameter changes in electrical impedance as sweat absorbs into the sensors. By measuring impedance variations and correlating them with the known absorption characteristics of each sensor, the processing unit can distinguish between volume changes and concentration changes, improving measurement accuracy.

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

Enables precise and reliable monitoring of sweat volume from the onset of perspiration, with extended measurement range and redundancy ensuring accurate sweat concentration tracking over time.

Implementation Method 1

each sensor comprising an absorption element capable of absorbing a volume of bodily fluid

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the processing unit being configured to determine an ionic concentration of the bodily fluid, based on the value of the electrical measurement data provided by the first sensor at saturation

Methodology Applied
Scientific EffectElectrical impedance: Electrical Resistance

Data Source

PatentEP4659669A1Device for monitoring the perspiration of a living being
Publication Date: 2025.12.10 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4659669A1 patent drawingFigure 1A~1B
  • EP4659669A1 patent drawingFigure 2
  • EP4659669A1 patent drawingFigure 3~4

AI summary

The invention relates to a device (1) for monitoring the perspiration of a living being, said perspiration causing the creation of a bodily fluid, said device comprising a support (10) having an active surface (100) intended to be applied against the skin (P) of a living being, said device comprising a processing unit (CU) and n sensors, with n greater than or equal to 2, each sensor (S1-Sn) being arranged on said active surface and connected to said processing unit (CU) to provide electrical measurement data, each sensor comprising an absorption element (2) capable of absorbing a volume of bodily fluid, the sensors being chosen with distinct bodily fluid absorption capacities so that a first sensor will reach saturation with bodily fluid more quickly than a second sensor.