Wearable Sweat Sensor with Radial Wicking and Capacitive Feedback
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Solution Overview
Problem
Current methods for monitoring hydration levels in humans are invasive, non-portable, or provide delayed indications, making them inefficient for real-time assessment, especially for high-performance athletes.
Innovation Solution
A wearable paper-based platform with a disposable wicking-based sweat collection patch and a reusable electronic module that provides simultaneous passive and active feedback, using a hygroscopic wicking material with a radial finger design for visual readout and capacitive sensing to alert users when a pre-determined volume of sweat is collected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods like serum ion concentration analysis are used, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent uses sweat as an intermediary substance that reflects hydration status without requiring direct blood sampling. The sweat collection patch captures sweat naturally secreted by the skin, which contains ion concentration information that correlates with serum ion concentration, thus providing accurate hydration assessment without invasive procedures
Solution Approach 2:
The patent replaces the mechanical/invasive blood sampling system with a passive sweat collection system. Instead of puncturing skin to obtain serum samples, the system uses a hydrophobic barrier and hydrophilic wicking material to passively collect sweat that naturally emerges through sweat glands, eliminating the need for needles or surgical intervention
2Ease of operation
If urine color or body mass methods are used, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent incorporates a colorimetric feedback mechanism where the wicking material contains indicators that change color based on sweat ion concentration. This provides real-time visual feedback about hydration status, allowing users to assess their hydration level accurately and immediately without waiting for laboratory analysis or indirect measurements
Solution Approach 2:
The patent utilizes color changes in the wicking material as a direct indicator of sweat composition and hydration status. The colorimetric response provides precise information about ion concentration in sweat, which correlates with serum ion concentration and thus accurate hydration assessment, while maintaining the simplicity of visual observation
3Ease of operation
If urine method is used, then ease of operation is improved, but loss of time worsens due to delayed indication
Solution Approach 1:
The patent performs preliminary sweat collection and analysis continuously throughout the day, so that hydration status is already assessed and indicated before the user needs to know it. The patch continuously collects sweat and the colorimetric indicators continuously reflect current hydration status, providing immediate information rather than delayed feedback after urine excretion
4Ease of operation
If a wearable sweat collection system is designed, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent divides the sensor platform into two independent modules: a disposable sweat collection patch and a reusable electronic module. The patch contains only the essential wicking material and hydrophobic barrier for sweat collection, while the electronic module handles detection and data processing. This segmentation allows the wearable patch to remain simple and comfortable, while complexity is concentrated in the separate electronic module
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 objective and timely quantification of sweat loss during physical activities, allowing users to assess hydration levels effectively and conveniently, with the system being robust, economical, and suitable for mass production.
Implementation Method 1
a first spacer centrally contacting a first side of the hygroscopic arrangement and configured to couple the hygroscopic arrangement to skin of a subject... an adhesive layer centrally adhered to a second side opposite to the first side of the hygroscopic arrangement and configured to affix the hygroscopic arrangement to the skin of the subject... such that hydration from sweating is allowed to wick to the common central region through the opening and traverse down each of the plurality of fingers
Data Source
AI summary
A wearable paper-based platform with simultaneous passive and active feedback for monitoring perspiration is provided. The sensor platform comprises two modules: a disposable wicking-based sweat collection patch with discrete colorimetric feedback, and a reusable electronic detachable module for active feedback. The disposable patch comprises a hygroscopic wicking material laminated between two polymeric films. The wicking material is patterned with a radial finger design that offers discretized visual readout of the sensor. The active module attaches to the film and alerts the user when the film collects a pre-determined volume of sweat. The multi-feedback system allows high-performance athletes who value objective quantification of perspiration to better assess their sweat loss during physical activities.