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Since most of the contact conduction type of heart sound sensors don’t take into account the acoustic signal attenuation problem caused by the heart sound signal transmitting to a sensor whose filling materials’ impedance is different to human soft tissue, the signal-to-noise ratio (SNR) of the heart sound sensors is not very well. Human heart is immersed in blood. If the sensor’s core sensitive element can be immersed in fluid, the attenuation of heart sound signal may be decreased greatly. Inspired by the principle of hydroacoustic signal’s detection, this paper proposes the design of heart sound sensor based on the bionic vector hydrophone. Then theoretical analysis and finite element method (FEM) simulation about the sensor have been carried out. Combined sensitivity with resonant frequency, the optimum dimension of the sensor’s structure has been determined. The sensor’s micro-structure has been fabricated by using Micro-Electro-Mechanical System (MEMS) technology and coupling encapsulated by choosing a kind of medical coupling agent as the filling material. Finally, the performance of the proposed sensor is tested. The fact is that the proposed sensor can work well with either healthy people or patients with heart disease. The obtained data clearly show that: the SNR of the proposed heart sound sensor is superior to 3200-type of 3M Littmann 8.2 dB.

Inspired by the hairy structure of fish neuromast, a multiple sensor units (multi-unit) vector hydrophone is proposed in the paper, which integrates multiple sensor units on one chip according to bionics. Its sensitivity and signal noise ratio (SNR) are theoretically analyzed compared with the hydrophone which has only one sensor unit. In order to verify the correctness of the theory, a 4-unit vector hydrophone has been fabricated. For experiments, the comparative calibration experiment is used to validate the theoretical analysis of sensitivity and fast fourier transform algorithm (FFT) is used to process the experiment data to verify the theoretical analysis of SNR. The results show that the sensitivity of the 4-unit hydrophone is improved by 11.8 dB and the SNR is improved by 1.9 dB on average, which is correlated with the theoretical analysis.