BracelHertZ

Overview

Developed in collaboration with a partner representative from the Portuguese Prison System through a university initiative, BracelHertz was designed to address a critical challenge in correctional facilities: inmate suicide prevention.

Scientific literature links specific anomalous heart rate patterns and sudden biometric spikes to acute emotional distress and suicidal attempts. To leverage these findings, our team developed a complete telemetry solution consisting of custom wearable hardware paired with a centralized management dashboard to detect and flag high-risk biometric patterns in real time.

Hardware & Wearable Prototyping

This project served as my introduction to hardware engineering, microcontroller programming, and physical enclosure design.

• Biometric Sensors & Microcontrollers: Programmed an Arduino board from scratch in C++ to continuously capture pulse sensor data and transmit telemetry payload over network interfaces to our central backend.
• Enclosure Modeling: Designed and 3D-modeled a wearable wristband enclosure tailored for the physical constraints and safety requirements of a prison environment.

Backend Architecture & Security

The software platform was powered by Java and Spring Boot, acting as the central hub for processing real-time telemetry and supporting facility workflows.

• Hierarchical Role-Based Access Control (RBAC): To reflect the operational hierarchy of correctional facilities, the system implemented fine-grained permissions across three user tiers: Operational Staff, Supervisors, and Prison Directors.
• Failsafes & Security Redundancies: Integrated fail-safe protocols and credential safeguards to prevent accidental system overrides or data mishandling during high-stress alerts.
• Automated Risk Engine: Designed a rule-based alerting service that continuously evaluated incoming telemetry against research-backed threshold parameters, immediately raising priority flags on the dashboard when abnormal heart rate spikes were detected.

Challenges & Retrospective

BracelHertz was an ambitious undertaking as one of my first web development projects. We were tasked with self-teaching Spring Boot and microcontroller programming simultaneously, with minimal external guidance.

Bridging bare-metal Arduino hardware with an enterprise Java backend required learning object-oriented backend patterns and asynchronous data flow on the fly. Despite the steep learning curve, seeing real-time biometric telemetry transmit from a custom wristband to a live, web-based dashboard was immensely rewarding.

The project earned us yet another perfect score (20/20) and demonstrated the power of combining IoT hardware with full-stack software to solve real-world human problems.