Comparative Assessment of PPG-Derived HRV Using MAX30102 Sensor and Analog Circuitry with ADS1115 ADC

Area of Science:

• Biomedical Engineering
• Physiological Monitoring
• Wearable Technology

Background:

• Heart rate variability (HRV) is crucial for assessing autonomic nervous system function and cardiovascular health.
• Photoplethysmography (PPG) is widely used in wearable devices for deriving HRV metrics.
• Existing PPG-based HRV monitoring systems face challenges in cost and flexibility.

Purpose of the Study:

• To compare the accuracy of basic HRV metrics derived from a MAX30102 optical sensor and a custom analog circuit with an ADS1115 ADC.
• To evaluate the performance of a novel analog acquisition system for PPG signal processing.
• To demonstrate a low-cost, flexible alternative for HRV monitoring.

Main Methods:

• Simultaneous PPG signal acquisition using MAX30102 and custom analog circuitry with ADS1115 ADC.
• Application of consistent analog and digital filtering pipelines to preserve HRV-relevant frequency bands.
• Extraction of inter-beat intervals to calculate Standard Deviation of NN intervals (SDNN), RMSSD, and pNN50.
• Bland-Altman analysis for evaluating agreement between the two measurement methods.

Main Results:

• The custom analog circuit with ADS1115 achieved comparable basic HRV metrics (SDNN, RMSSD, pNN50) to the MAX30102 sensor.
• The analog circuit demonstrated an improved Signal-to-Noise Ratio (SNR) due to high-resolution ADC and low-noise amplification.
• Bland-Altman analysis confirmed good agreement between the two measurement pathways.

Conclusions:

• A carefully designed analog acquisition system can reliably reproduce basic HRV parameters from PPG signals.
• The custom analog circuit offers a viable, low-cost alternative for flexible biosensing platforms.
• This approach enhances the potential for widespread adoption of PPG-based HRV monitoring.