This project focuses on the development of a next-generation wearable smart ring designed for continuous health monitoring and activity tracking in an ultra-compact form factor. Unlike conventional wristbands or smartwatches, the ring form factor introduces unique challenges in miniaturization, power optimization, and sensor integration, making the design both innovative and technically demanding.

At the heart of the device is the nRF52832 Bluetooth Low Energy (BLE) microcontroller, which provides reliable wireless communication, efficient processing, and low power consumption. This SoC serves as the brain of the system, coordinating data from sensors, managing power, and ensuring seamless connectivity with smartphones and external applications.

Health Monitoring & Optical Sensing

The device integrates the AS7038RB optical biosensor, which enables real-time measurement of blood oxygen saturation (SpO₂) and heart rate. Its miniature footprint and optimized optical design allow for precise detection despite the limited surface area of a ring. Paired with custom LEDs (CH DELSS1.22), the system achieves accurate readings even in dynamic, real-life conditions.

Motion & Activity Tracking

To expand beyond biometrics, the smart ring incorporates the LIS2DTW12TR accelerometer, a high-performance 3-axis motion sensor with built-in step recognition and temperature measurement. This enables advanced activity tracking features such as step counting, gesture recognition, and posture detection — all while keeping power consumption minimal.

Power Management & Battery Design

Miniaturization requires extreme attention to energy efficiency. The design combines two power management ICs:

• RP605 step-down regulator for compact, high-efficiency voltage conversion.
• ISL9120IIAZ-T7A dynamic voltage regulator, which intelligently scales power usage depending on operating conditions.

These regulators work together to maximize battery life while maintaining reliable sensor operation. The system is powered by a GRP1507025 lithium-polymer rechargeable battery, chosen for its ultra-thin profile and high energy density, making it a perfect fit for wearable applications where every millimeter matters.

System Integration & Mechanical Design

The electronic architecture is implemented on a ds-000157 flexible PCB substrate, which allows the circuitry to conform to the ring’s circular shape while preserving mechanical durability and electrical performance. This design choice not only reduces space but also ensures ergonomic comfort for the user.

Result

The result is a sleek, low-power wearable device that combines advanced health monitoring (SpO₂, heart rate), activity recognition (steps, motion, temperature), and wireless connectivity in an elegant ring design. This project demonstrates expertise in sensor fusion, miniaturized electronics, flexible PCB design, and ultra-low-power optimization — all critical skills for modern wearable technology development.