wearable heart sound sensor, digital auscultation sensor, lung sound monitoring sensor, phonocardiography sensor, cardiac acoustic sensor
Auscultation Microphone for Robust Heart and Lung Sound Monitoring
Advanced digital auscultation sensor optimized for high-quality heart and lung sound pickup under real-world conditions, designed for integration into the PCARDIO wearable monitoring platform.
- Raw audio up to 16 kHz
- Embedded data reduction
- Optimized for heart & lung sounds
- USB raw data collection
- S1–S4 extraction algorithms available
TECHNICAL OVERVIEW
Engineering-Grade Digital Auscultation Platform
The PCARDIO wearable heart sound sensor is designed for organizations developing next-generation physiological monitoring systems. Unlike standard microphones, this sensing module has been optimized specifically for reliable acquisition of clinically relevant cardiac and respiratory sounds.
The device captures raw acoustic signals up to 16 kHz, enabling detailed recording of heart sounds, lung sounds, murmurs, airflow events, and other bioacoustic phenomena.
Extensive engineering effort has been invested in mechanical coupling, acoustic pickup quality, and robust signal capture so the sensor also performs in challenging environments.
WEARABLE INTEGRATED
Optimized for Wearable Monitoring
This wearable heart sound sensor is designed to operate inside real monitoring systems rather than only in laboratory conditions.
Typical challenges addressed include:
- motion artifacts
- body contact variability
- environmental noise
- limited data bandwidth
- long-duration monitoring requirements
- synchronized multi-sensor operation
The result is a practical solution for real-world wearable auscultation.
EMBEDDED PROCESSING
Embedded Processing and Smart Data Reduction
Continuous raw audio streaming can generate large datasets. Therefore, the platform includes dedicated embedded microcontroller processing that can:
- downsample acoustic data intelligently
- reduce data size using custom algorithms
- preserve diagnostically relevant information
- optimize streaming for PCARDIO wearable systems
- enable longer battery operation
This creates an efficient balance between signal quality and wearable usability. The embedded processing allows the acoustic channel to be matched to for example the PCARDIO data architecture without simply discarding relevant signal content. The exact strategy can be adapted to the target use case, whether the goal is long-duration monitoring, synchronized multimodal analysis, or exploratory raw data collection.
Embedded Processing and Smart Data Heart Sound Analytics (S1–S4)
PCARDIO has algorithms available to extract heart sound features including S1, S2, S3, and S4. This supports use cases where the interest is not only in storing raw auscultation data, but also in obtaining structured events and features for scientific analysis, algorithm development, and system integration.
This supports:
- AI model development
- cardiac timing analysis
- digital phonocardiography research
- heart failure studies
- wearable diagnostic innovation
USB Raw Data Collection for Research
For engineering teams and scientific users, the device can also operate via USB 16kHz raw data mode for direct acquisition of high-fidelity sound data.
Ideal for:
- signal analysis
- machine learning datasets
- validation studies
- custom filtering research
- acoustic biomarker discovery
Two complementary operating modes
Embedded platform mode: optimized streaming and integration into PCARDIO workflows using dedicated embedded processing.
USB raw mode: direct access to richer raw acoustic data for engineering, scientific analysis, and algorithm development.
PERFORMANCE
Performance benchmark against commercial electronic stethoscopes
The acoustic performance of the 2M-Chestpiece was benchmarked against two established commercial electronic stethoscopes: the 3M Littmann 3200 and the Eko Core.
Rather than repeating in-house measurements on these reference devices, published acoustic characterization data were used where available. The frequency-response comparison is based on the peer-reviewed study by Arjoune et al. (2023), which characterized several digital stethoscopes, including the Littmann 3200 and Eko Core, and reported significant inter-device differences in frequency response. Additional signal-to-noise comparison was made against published data for the Littmann 3200 from an IEEE Access study on MEMS-based electronic stethoscope design.
Frequency response
The 2M-Chestpiece shows a broad and balanced response across the cardiac auscultation band. In our measurements, the response remains within approximately −6 dB from 50 Hz to 200 Hz, with a peak around 150 Hz. A stronger roll-off is observed at 40 Hz, which is consistent with the mechanical low-frequency limitations of a compact wearable chestpiece and silicone coupling layer.
In comparison, the published response of the Littmann 3200 shows a stronger low-frequency emphasis, while the Eko Core shows reduced sensitivity at the lower end of the cardiac band and a gradual rise toward higher frequencies. This means that the 2M-Chestpiece offers a more uniform passband across the range relevant for both low-frequency heart sound components such as S1 and S2 and mid-frequency components such as murmurs.
For a wearable monitoring device, this flatness is important: it supports consistent signal capture across a broader part of the cardiac auscultation spectrum, rather than emphasizing only a narrow frequency region.
Signal-to-noise ratio
The signal-to-noise ratio of the 2M-Chestpiece was measured at approximately 30 dB using the waveform amplitude method. Published data for the 3M Littmann 3200 reports an SNR of approximately 31.1 dB under comparable heart-sound measurement conditions.
This indicates that the 2M-Chestpiece achieves signal quality in the same range as an established hand-held commercial electronic stethoscope, while using a compact wearable form factor designed for continuous physiological monitoring.
Practical relevance
The result is not only relevant from an acoustic perspective, but also from a system-design perspective. Conventional electronic stethoscopes are primarily designed for short, clinician-led auscultation sessions. The 2M-Chestpiece is designed as part of a wearable sensing platform for longer-duration monitoring, where stable attachment, compact size, repeatable signal acquisition and integration with other physiological signals are essential.
In summary, the 2M-Chestpiece demonstrates:
| Parameter | 2M-Chestpiece result | Practical meaning |
|---|---|---|
| Frequency response | Within approx. −6 dB from 50–200 Hz | Broad coverage of the cardiac auscultation band |
| Peak sensitivity | Around 150 Hz | Suitable for relevant heart-sound components |
| Low-frequency roll-off | Approx. −12.6 dB at 40 Hz | Expected limitation of compact wearable coupling |
| SNR | Approx. 30 dB | Comparable to published Littmann 3200 reference data |
| Form factor | Compact wearable chestpiece | Suitable for continuous monitoring rather than only spot-check auscultation |
Conclusion: the 2M-Chestpiece combines a broad cardiac-band frequency response with signal-to-noise performance close to a leading commercial electronic stethoscope, while enabling a compact wearable design for continuous monitoring applications.
POSSIBLE APPLICATIONS
Use cases for engineering teams, researchers, and product developers
Clinical and translational research
- Heart sound recording and annotation studies
- Lung sound capture in ambulatory or semi-controlled environments
- Multimodal physiological monitoring combined with ECG, motion, respiration, or other wearable signals
- Algorithm development for classification, segmentation, and event detection
Product development and embedded innovation
- Development of advanced auscultation-enabled wearables
- Feasibility studies for long-duration acoustic monitoring under constrained bandwidth conditions
- Evaluation of robust acoustic pickup under noisy or mechanically challenging conditions
- Integration into custom OEM platforms for health monitoring, remote care, or operational physiology
WHY PARDIO
Designed around signal usefulness, not just sensor presence
Many acoustic sensing concepts can capture sound in principle. The engineering challenge is to capture the right sound with sufficient consistency and quality when the sensor must operate inside a wearable or applied monitoring system. This module has been developed with that challenge in mind: preserving clinically and scientifically relevant information while fitting within a scalable embedded platform.
For teams working on next-generation physiological monitoring systems, this provides a practical route from raw auscultation acquisition to usable features, synchronized data streams, and product-oriented system integration.
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