Eye Gaze Wearable Impact Detection System

Jorge, USA

The primary technical challenge involved isolating specific impact events from general swing kinematics using a low-power microcontroller. The system necessitated the empirical determination of 3-axis accelerometer thresholds to accurately trigger interrupts without false positives. Furthermore, the architecture required strict power optimization to maximize battery life within a compact, racket-mounted form factor.

Developed a prototype integrating a 3-axis accelerometer to identify sudden acceleration spikes corresponding to ball impacts. For the initial phase, the firmware executes basic threshold-based impact detection logic with a configuration mode.

Successfully engineered a functional wearable device that visually signals impact events based on configurable user parameters. The initial production run yielded 10 fully functional prototypes, complete with custom enclosures and printed circuit boards, for field evaluation.

Designed a compact, wearable PCB utilizing a 3-axis accelerometer and microcontroller options including STM32, ESP32, or MSP430 series components. Implemented a threshold-based interrupt system where motion data wakes the microcontroller from Low Power Mode (LPM3) to execute impact logic. Integrated four Tri-color R/G/Y LEDs and an external LED strip interface for optimized visual feedback. Engineered a hardware architecture compatible with advanced impact detection, establishing the foundation for future implementation of DSP and FFT algorithms for frequency domain analysis. Fabricated custom 3D-printed plastic housings with Velcro wrist strap integration.

Provided a quantifiable, configurable feedback mechanism for sports training applications. Visual indication duration can be precisely calibrated in 0.1-second increments up to a limit of 1.0 second (10 button presses), allowing tailored feedback for different swing speeds and drills. Established a scalable hardware foundation, allowing the current threshold-based system to upgrade to complex algorithm processing without complete hardware redesign. Minimized component footprint and power consumption by eliminating external voltage regulators, utilizing the microcontroller's internal reference for low voltage detection. Reduced overall BOM (Bill of Materials) cost, keeping the total component budget under $100 for the initial 10-unit batch.

Project Timeline: 7-week end-to-end development cycle encompassing electronic design, mechanical fabrication, and firmware development. Project Budget: Delivered 10 fully functional prototype units within a strict $2,070 total project budget covering design, fabrication, assembly, and testing. Development Phases: Component Procurement -> PCB Schematic & Layout -> Mechanical 3D Printing -> Basic Version Firmware (Threshold Logic) -> Testing & Debugging.

Power Constraints: Engineered to operate exclusively on a 3V CR2450 coin cell, maximizing Low Power Mode (LPM3) with all unused pins grounded to eliminate parasitic draw. The board was also designed with forward compatibility for rechargeable LiPo batteries. Kinematic Tolerances: The 3-axis accelerometer and associated housing mounts were engineered to withstand the high shock and vibration transfer from a tennis racket or golf club shaft during physical ball impact. Low Voltage Protection: Operates without a dedicated external voltage regulator; instead, it leverages the microcontroller's internal 2.5V reference to detect low voltage states and execute controlled system shutdowns.