Project Title: Wearable Health Monitor Device – A Secure, Multi-Sensor Health Tracker

Team Members: Qinwen Deng, Nam Vu
Course: ECE 414 – Embedded Systems

Project Overview

In response to the high cost of commercial health wearables, this project aimed to design and implement a cost-effective, embedded wearable health monitor. The device integrates an array of essential sensors to track key physiological and environmental metrics, providing users with valuable health data. A focus on accessibility and data privacy ensures the device is both practical and secure for personal use.

Key Features & Objectives

The system was designed with the following core capabilities:

  • Secure User Authentication: The device is locked on startup and requires a specific RFID card to unlock, ensuring user data privacy.

  • Comprehensive Health Monitoring: Once unlocked, the device displays real-time data including:

    • Heart Rate (BPM) from a pulse oximeter.

    • Ambient Temperature and Humidity.

    • Ambient UV Index.

    • User motion via accelerometer magnitude.

  • Visual Heartbeat Feedback: An LED matrix synchronizes its flashing pattern with the user’s detected heart rate, providing a clear visual indicator of pulse.

  • Real-Time Data Display: A colorful and intuitive LCD touchscreen interface presents all sensor data, updating every second to provide immediate feedback.

Technical Implementation

Hardware Core:
The device is built around a single Raspberry Pi Pico (RP2040) microcontroller that integrates a wide array of sensors and peripherals:

  • Microcontroller: Raspberry Pi Pico (RP2040)

  • User Interface: Adafruit 2.4” TFT LCD Touchscreen (SPI)

  • Biometric Sensor: MAX30102 Pulse Oximeter and Heart-Rate Sensor (I2C)

  • Environmental Sensors:

    • DHT20 Temperature and Humidity Sensor (I2C)

    • LTR390 UV Sensor (I2C)

  • Motion Sensor: MPU6050 Accelerometer and Gyroscope (I2C)

  • Security: RC522 RFID Reader (SPI) for user authentication.

  • Visual Feedback: IS31FL3731 LED Matrix Driver (I2C)

Software & Framework:

  • Framework: Arduino

  • Architecture: The software is structured around a Finite State Machine (FSM) with two primary states: DEVICE_LOCK (waiting for RFID) and DEVICE_UNLOCK (active monitoring).

  • Integration: A single main file orchestrates the reading of all sensors, data processing, and display updates, leveraging specialized libraries for each hardware component.

Challenges & Adaptations

The project involved significant integration challenges that were successfully overcome:

  • Multi-Sensor Integration: Coordinating six different I2C and SPI devices on a single microcontroller required careful management of pin assignments and communication protocols.

  • Library Compatibility: Sourcing and integrating multiple third-party libraries from GitHub for the various sensors was a complex task essential for functionality.

  • Power Management: Ensuring stable 3.3V power for all components from the Pico was critical for reliable sensor readings.

  • User Interface: Designing a clear and informative display layout to present multiple data streams simultaneously without cluttering the screen.

Results & Demonstration

The final prototype successfully operates as a proof-of-concept health monitor. The device:

  • Securely remains in a locked state until the correct RFID card is presented.

  • Unlocks and immediately begins displaying real-time sensor data on the LCD.

  • Accurately measures and displays heart rate, with the LED matrix flashing in sync with the user’s pulse.

  • Reliably reports temperature, humidity, UV index, and motion data.

  • Updates all information on the screen at a rate of once per second, meeting the specified performance requirements.

Conclusion & Future Work

This project successfully demonstrates a functional, low-cost prototype for a multi-sensor health monitoring wearable. It effectively combines data privacy, user feedback, and a wide range of health and environmental metrics into a single, integrated device.

Potential future enhancements could include:

  • Integrating a GPS module to track user activity and distance traveled.

  • Associating RFID cards with personalized user profiles (name, age, weight) for customized health tracking.

  • Implementing a fully functional touchscreen interface for richer user interaction beyond the basic logout button.

  • Adding data logging capabilities to track health metrics over time.

The project required approximately 24 hours of work per team member over four weeks.