AR Navigation Glasses for Athletes

Overview

Lightweight athletic smart glasses providing real-time turn-by-turn GPS navigation through a micro-OLED heads-up display. Features sensor fusion with Extended Kalman Filter for accurate positioning, custom optics system, BLE connectivity for route management, and a web application for route planning and activity tracking. Complete hardware-software integration including custom PCB, battery management system, and 3D-printed frame.

Key Features

• Custom PCB with ESP32-S3, GPS (PA1616D), 9-axis IMU (BNO055), and battery management
• Optical system: micro-OLED display with prism assembly for non-intrusive HUD
• Extended Kalman Filter fusing GPS/IMU data for accurate real-time localization
• FreeRTOS-based firmware with layered architecture (HAL, Service Layer, Application FSM)
• Turn-by-turn navigation with waypoint tracking and "lost mode" recovery
• BLE GATT file transfer for route upload/download from web app
• Django web application with Mapbox integration for route creation and GPX parsing
• 4+ hour battery life with dual 800mAh LiPo batteries

Technical Challenges

End-to-end system integration across hardware, firmware, and software layers required extensive debugging of inter-component communication. Traced issues from PCB-level signal integrity (I2C/SPI/UART) through FreeRTOS task synchronization to web-BLE data transfer. Debugged sensor fusion pipeline where GPS NMEA parsing, IMU quaternion conversion, and EKF state updates had to coordinate reliably. Resolved timing issues between display rendering, navigation logic, and file system operations competing for SPI bus access.

Outcome

Successfully demoed at UMich CoE Design Expo with full end-to-end navigation in real-world testing. Achieved all milestone deliverables on schedule and under budget ($826 vs $1,500 allocated). System provides reliable turn-by-turn guidance with position accuracy suitable for outdoor athletics.

Technologies

• C
• C++
• FreeRTOS
• PCB Design