A Bionic MEMS Electronic Stethoscope With Double-Sided Diaphragm Packaging

In this paper, an electronic stethoscope is designed based on a bionic Micro-Electro-Mechanical System (MEMS) sound-sensitive sensor. Inspired by the strong sound reflection effect of the water-air interface, a double-sided diaphragm MEMS electronic stethoscope (DMES) encapsulated by a novel double-sided diaphragm packaging is proposed. The double-sided diaphragm packaging’s superiority is verified by comparing a single diaphragm MEMS electronic stethoscope (SMES) with DMES. The frequency of the clinical heart sound signal is mostly in the range of 20–600 Hz. Finite simulation results show that for the same incident sound source, the sound pressure level inside double-sided diaphragm packaging is 4dB higher than that of single diaphragm packaging in this frequency band. Furthermore, the actual auscultation test results show that the signal-to-noise ratio (SNR) of DMES reaches 41.3dB, which is 2.2dB higher than SMES. Besides, comparing the heart sound signals collected by DMES and a commercial electronic stethoscope (Model 3200, 3M Littmann, USA), the high consistency of the two signals’ characteristic parameters in the time domain and frequency domain proves the feasibility of DMES. Finally, DMES has the advantages of low cost, and its SNR is 10.2db higher than that of the 3M electronic stethoscope. All these show that DMES has a broad prospect in the popularization of basic medical treatment.