Real-Time Heart Rate and SpO₂ Monitoring System with STM32F446RE

Overview

This project demonstrates a real-time heart rate and SpO₂ monitoring system using the STM32F446RE Nucleo board. It integrates the MAX301102 Pulse Oximeter and Heart-Rate Sensor for PPG signal acquisition, and the ILI9341 LCD for real-time signal visualization and user interaction. The system features custom drivers for efficient data acquisition, filtering, peak detection, and parameter estimation.

Features

PPG Signal Acquisition:

• Interfacing with MAX301102 using I2C for heart rate and SpO₂ data acquisition.
• Custom I2C communication driver to manage sensor data and interrupts efficiently.

Real-Time Signal Filtering:

• Moving Average Filter to smooth raw PPG signals.
• Drift Removal Filter to eliminate DC offset from the signal.
• User control via the LCD touch interface to toggle the filter on/off.

Finger Detection:

• Real-time detection of finger placement on the MAX301102 sensor.
• Visual feedback on the LCD display with a heart icon.
• Automatic suspension of peak detection and SpO₂ estimation when no finger is detected.

Peak Detection Algorithm:

• Real-time peak detection based on adaptive thresholding.
• Algorithm based on IEEE paper: A Real-Time QRS Complex Detector Based on Adaptive Thresholding (https://ieeexplore.ieee.org/abstract/document/7138573).

Heart Rate Calculation:

• Heart rate calculation based on the time between detected peaks.

SpO₂ Estimation:

• Real-time SpO₂ estimation using the Red and IR PPG signals from the MAX301102 sensor.
• Display of the SpO₂ value on the LCD.

Real-Time Data Visualization:

• Display of raw and filtered PPG signals, heart rate, SpO₂, and temperature on the ILI9341 LCD.
• Touch-based control to adjust signal gain and toggle filters.

Hardware Setup

• STM32F446RE Nucleo Board
• MAX301102 Pulse Oximeter & Heart-Rate Sensor
  • Interface: I2C
• ILI9341 LCD Display
  • Interface: SPI

Software Components

• STM32 HAL Libraries
• Custom Drivers for MAX301102 and ILI9341

Usage

1. Place a finger on the MAX301102 sensor and enable MA Filter.
2. Observe the heart icon on the display for finger detection status.
3. Monitor heart rate, SpO₂, and temperature in real-time.
4. Use the LCD touch interface to adjust signal gain and toggle filters.

Connection

Device

• Original Signal Distorted by Noise

• Signal Smoothing using Low-pass Filter