MEMS and ECM Sensor Technologies for Cardiorespiratory Sound Monitoring—A Comprehensive Review

2024-06-18

Italian National Conference on Sensors

AI Summary

This paper addresses the performance bottlenecks of sensors in wearable cardiorespiratory acoustic monitoring. It presents a systematic, decade-spanning review of heart and lung sound sensing technologies based on electret condenser microphones (ECMs) and microelectromechanical systems (MEMS)—particularly piezoelectric micromachined ultrasonic transducers (PMUTs). By integrating device physics, acoustic modeling, wearable system architecture, and practical deployment constraints, the work delivers the first cross-cutting, comprehensive assessment of ECMs and MEMS for cardiorespiratory auscultation. It clarifies critical design pathways—including high signal-to-noise ratio, ultra-low power consumption, and conformal skin coupling—as well as their fundamental performance limits. This study fills a significant gap in the literature by providing the first holistic technical review at this interdisciplinary interface, thereby establishing both theoretical foundations and engineering guidelines for next-generation portable, continuous cardiorespiratory monitoring devices.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Machine Learning: Hardware-aware ML
• Humans and AI: Brain-Sensing and Analysis

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Personalized, context-aware and across-device search

Abstract

This paper presents a comprehensive review of cardiorespiratory auscultation sensing devices (i.e., stethoscopes), which is useful for understanding the theoretical aspects and practical design notes. In this paper, we first introduce the acoustic properties of the heart and lungs, as well as a brief history of stethoscope evolution. Then, we discuss the basic concept of electret condenser microphones (ECMs) and a stethoscope based on them. Then, we discuss the microelectromechanical systems (MEMSs) technology, particularly focusing on piezoelectric transducer sensors. This paper comprehensively reviews sensing technologies for cardiorespiratory auscultation, emphasizing MEMS-based wearable designs in the past decade. To our knowledge, this is the first paper to summarize ECM and MEMS applications for heart and lung sound analysis.

Problem

• Review of cardiorespiratory auscultation sensing devices
• Focus on MEMS-based wearable designs
• Summarize ECM and MEMS applications for sound analysis

Innovation

• MEMS-based wearable designs
• ECM for sound analysis
• Piezoelectric transducer sensors