# Modeling Capacitive Sweat Rate Sensor

- Organization: [Khan Lab, USC](https://khan.usc.edu/)
- Role: Coauthor of Paper Published in Advanced Intelligent Systems
- Dates: Dec 2024
- Supervisor: Professor Yasser Khan
- Topics: Wearable sensors, Microfluidics, Fusion 360, Scientific figures
- Page: https://www.cedarroseleach.com/work/sweat-rate-sensor/

> Co-authored a paper in Advanced Intelligent Systems on a fully printed, flexible sweat rate sensor, and built the 3D CAD models used in its published figures.

Links:
- [View Full Paper](https://doi.org/10.1002/aisy.202400927)

Publications:
- Journal article: Mohammad Shafiqul Islam, Sangwon Cha, Md Farhad Hassan, Wenxin Cai, Tahsin Sejat Saniat, Cedar Rose Leach, Yasser Khan "Printed wearable sweat rate sensor for continuous in-situ perspiration measurement." Advanced Intelligent Systems, December 25, 2024. https://doi.org/10.1002/aisy.202400927

## Abstract

> Sweat rate measures key physiological states such as hydration levels and heat tolerance. Incorporating wearable technology with sweat rate sensors allows individuals to conveniently monitor their health, optimize workouts, and enhance occupational safety. However, challenges persist in such integration techniques, including intricate manufacturing, nonlinear responses to changes in sweat rates, and errors from the intermediate measurement of the distance sweat travels in the sensor. To address these issues, we present a comprehensive wearable platform that includes a fully printed, flexible sensor patch, readout electronics, and a mobile app for continuous, real-time monitoring of sweat rate. We fabricate a sensor patch with an area of 700 mm² and a weight of 380 mg by utilizing direct 3D printing and scalable microfluidic fabrication. The microfluidic channels are 850 μm wide and 164 μm thick, with serpentine electrodes measuring sweat rate using capacitance...

## My Contribution

I helped to visualize and communicate the design of our wearable capacitive sweat sensor by creating detailed 3D models of the capacitive sweat rate sensor in Fusion 360.

Effective communication is one of the most crucial aspects of any advancements in science, and my hope is that I could enhance the understanding and appreciation of our lab's capacitive sweat sensor. Through detailed CAD models, I highlighted the sensor's structural layers, design features, material composition, and functionality. Here are some of the published designs:

Figures:
- Three layers of the sweat rate sensor. Bottom layer - the encapsulated Ag electrodes on a flexible polyimide substrate. Middle layer - the patterned microfluidics channel to direct the sweat. Top layer - microfluidics cover. Both the substrate and microfluidic layers are hydrophilic, so they generate a capillary force that directs sweat into the dielectric channel.
- Capacitive system for the analytical modeling of the sweat rate sensor. Capacitance is formed by the sweat and the air within the dielectric channel. Dielectric encapsulation and the two parallel metal electrodes are shown.
- Fabrication process - direct 3D writing of two parallel Ag electrodes.
- Fabrication process - direct 3D writing of dielectric encapsulation.
- Fabrication process - assembly of a double-sided microfluidic tape, patterned by using a desktop cutter machine, with the already encapsulated Ag electrodes.
- Fabrication process - assembly of a microfluidic cover, patterned by using the same desktop cutter machine, concluding the sensor fabrication.

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By Cedar Rose Leach (cdleach@usc.edu). Site summary: /llms.txt