Heart Rate Monitor Tutorial

The concepts of Heart Rate measurement using reflective photoplethysmography (PPG) along with some of the basic digital signal processing (DSP) techniques are demonstrated. PPG waveforms are displayed and your heart rate is calculated. Signal processing controls are provided for experimenting with different DSP techniques on heart rate measurement. 

DSP techniques discussed in the tutorial sections include:
- recursive high-pass filter
- recursive low-pass filter
- signal source and signal to noise ratio (SNR)
- sampling rate

The main SwiftUI code for the demo is provided for reference or as a starting point for further investigation.