Smart Ring Resize and Window Casting

This project involved scaling a prototype smart ring to support additional sensing functionality while maintaining compatibility with an existing flex PCB. The work also focused on developing sealed, optically clear windows to protect internal electronics during on-body testing, with an emphasis on manufacturability and rapid iteration.

Objectives:
-Redesign smart ring prototype to fit larger finger while maintaining compatibility with existing flex PCB layout to integrate new vital sign modality
-Seal ring windows with waterproof optically clear windows to protect PCB during on body testing

Ring Scaling Approach:
-Modeled a scalable parametric ring design in SolidWorks with adjustable radii and window position
-Created Excel-based variable tracking system to streamline design iterations
-SLA 3D printed iterations to fit test mockup of flex PCB
-Adapted design for external fabrication using lost-wax casting and 3D printing in copper and brass

Developed and tested window sealing methods including:
-Using 3M medical diagnostic tape on inner surface of ring
-Photopolymerizing Resin deposition and curing approach

For Resin approach:
-Designed parametric molds in SolidWorks using variables to help with iteration
-SLA printed and tested many mold iterations
-Developing a repeatable process for creating resin windows

Challenges:
-Ensuring ring material compatibility with PCB sensors for accurate performance
-Redesigning ring geometry for machinability while preserving functional constraints
-Developing a repeatable process for creating resin windows for sensor visibility

Skills Learned/Reinforced:
-CAD and Modeling: SolidWorks parametric design, design tables
-Prototyping and Fabrication: SLA printing, mold creation, rapid prototyping
-Design Principles: Design for manufacturing, tracking critical parameters

Impact and Value:
-Parametric SolidWorks design enables rapid future adjustments to ring radius and window spacing without redesign
-Successfully produced waterproof, optically clear windows for sensor visibility, validating sealing approach
-Demonstrated feasibility of scaling ring for larger battery while maintaining compatibility with existing PCB
-Established a flexible design and manufacturing workflow that supports iterative prototyping