CN107260206B - Electronic stethoscope based on MEMS (micro-electromechanical systems) sound sensing principle - Google Patents
Electronic stethoscope based on MEMS (micro-electromechanical systems) sound sensing principle Download PDFInfo
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- CN107260206B CN107260206B CN201710553457.9A CN201710553457A CN107260206B CN 107260206 B CN107260206 B CN 107260206B CN 201710553457 A CN201710553457 A CN 201710553457A CN 107260206 B CN107260206 B CN 107260206B
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B7/00—Instruments for auscultation
- A61B7/02—Stethoscopes
- A61B7/04—Electric stethoscopes
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B7/00—Instruments for auscultation
- A61B7/003—Detecting lung or respiration noise
Abstract
The invention relates to an electronic stethoscope based on MEMS (micro-electromechanical systems) sound sensing principle, which comprises a sound pick-up head shell, wherein a polyurethane sound transmitting cap and a packaging base are respectively fixed at two ends of the sound pick-up head shell; the sound head shell is connected with the handheld support body through a cylindrical connecting pipe with a built-in lead, a signal processing circuit board and a power supply are installed in the handheld support body, the signal processing circuit board is connected with the sound sensor microstructure through the lead, and the power supply supplies power to the signal processing circuit board and the sound sensor microstructure. The stethoscope of the invention utilizes an acoustic sensor processed by MEMS technology as a sensitive element for receiving acoustic signals, combines the processing functions of modules on a signal processing circuit board, ensures that received cardiopulmonary sound signals are more accurate, simultaneously sends heart sound, heart rate and respiratory sound signals collected in real time to a client through a Bluetooth module for real-time display and analysis, and calculates conventional parameters such as heart rate and the like through corresponding algorithms.
Description
Technical Field
The invention relates to an intelligent biomedical device, in particular to an electronic stethoscope based on the MEMS sound sensing principle.
Background
The current clinical main diagnostic tool for cardiovascular and cerebrovascular diseases and respiratory diseases is still auscultation of heart sounds and respiratory sounds. The traditional stethoscope is mainly used for calculating the heart rate by doctors according to the heart beat frequency, signals are weak, low-frequency response is poor, diagnosis depends on subjective judgment of doctors to a large extent, human ears have inherent limitation (the frequency range most sensitive to hearing is between 1kHz and 3 kHz), sensitivity to low-frequency sound is poor, the frequency range of heart sounds with clinical value is usually concentrated in the range of 20Hz to 600Hz, and therefore pathological features of low-frequency and low-intensity heart sounds (such as second heart sounds and the like) with important diagnostic significance are difficult to capture.
Disclosure of Invention
The present invention is directed to solve the above problems of the prior art, and provides an electronic stethoscope based on MEMS acoustic sensing principle. The stethoscope is an electronic stethoscope which is designed based on MEMS technology, can auscultate and display waveforms in real time, and has high signal-to-noise ratio and low cost.
The invention is realized by the following technical scheme:
the utility model provides an electronic type stethoscope based on MEMS acoustic sensing principle which characterized in that: the acoustic sensor comprises a sound pick-up head shell, a polyurethane sound-transmitting cap, a packaging base, an acoustic sensor microstructure, a cylindrical connecting pipe and a handheld supporting body; two ends of the sound head shell are open, and an oil injection hole is formed in the shell wall of the sound head shell; the polyurethane sound-transmitting cap is packaged at the open end of one end of the sound-collecting head shell, and the packaging base is packaged at the open end of the other end of the sound-collecting head shell; the acoustic sensor microstructure is arranged in the sound pick-up head shell and is fixed on the packaging base through a round PCB (printed circuit board), the acoustic sensor microstructure comprises four piezoresistors, namely a rectangular supporting frame, a rectangular strain gauge, a cantilever beam and a piezoresistor, the rectangular supporting frame is fixed on the round PCB, the rectangular strain gauge is suspended at the central position of the rectangular supporting frame through the cantilever beam, two piezoresistors are distributed on the cantilever beam, the rest two piezoresistors are distributed on the frame edge of the rectangular supporting frame connected with the cantilever beam, and the four piezoresistors are connected into a Wheatstone bridge; one end of the cylindrical connecting pipe is connected with the shell wall of the sound pick-up head shell, the other end of the cylindrical connecting pipe is connected with the handheld supporting body, and a lead is arranged in the cylindrical connecting pipe in a penetrating manner; a signal processing circuit board and a power supply are arranged in the handheld support body, and a power supply voltage supply module, an adjustable voltage-stabilized power supply module, a signal conditioning module, a signal acquisition module, a data storage module and a Bluetooth module are arranged on the signal processing circuit board; the signal processing circuit board is connected with the acoustic sensor microstructure through a lead in the cylindrical connecting pipe, and the power supply supplies power to the signal processing circuit board and the acoustic sensor microstructure; the inner cavity of the sound head shell is filled with silicone oil with good sound conduction performance through the oil injection hole.
The stethoscope provided by the invention uses the sound sensor microstructure processed by the MEMS technology as a sensitive unit to be applied to a listening part of the stethoscope and as a receiving device of a heart sound signal, and realizes the acquisition of the heart sound signal through the coordination of signal conditioning and signal acquisition.
As the preferred technical scheme, the sound head shell is in a round table shape, the polyurethane sound-transmitting cap is packaged at the large open end of the sound head shell, and the packaging base is packaged at the small open end of the sound head shell.
The stethoscope of the invention uses an acoustic sensor processed by MEMS technology as a sensitive element for receiving acoustic signals, combines the processing functions of modules on a signal processing circuit board, ensures that heart and lung sound signals are heard more accurately, simultaneously sends heart sound, heart rate and breath sound signals collected in real time to a client through a Bluetooth module for real-time display and analysis, and calculates conventional parameters such as heart rate and the like through corresponding algorithms. The function of the stethoscope of the invention shows the practicability of the MEMS stethoscope, and the clinical experience can be further combined to give a preliminary diagnosis result so as to improve the accuracy of heart lesion diagnosis or fetal heart monitoring of children. In addition, the stethoscope has the advantages of small volume, high sensitivity, low cost and capability of wirelessly transmitting the waveform and the heart sound digital characteristics to clients such as a mobile phone and the like, and is clearer and more convenient for detecting the heart rate compared with the traditional stethoscope.
Drawings
Fig. 1 is a schematic diagram of the back structure of the stethoscope of the present invention.
Fig. 2 is a schematic front view of the stethoscope according to the present invention.
FIG. 3 is a schematic structural diagram of a circular PCB and a microstructure of an acoustic sensor in the stethoscope according to the present invention.
Fig. 4 is a block diagram of the connection of the modules on the signal processing circuit board of the stethoscope of the present invention.
FIG. 5 is a stress cloud plot of the microstructure of an acoustic sensor in a stethoscope according to the present invention.
Fig. 6 is a first-order mode diagram of the microstructure of the acoustic sensor in the stethoscope according to the present invention.
FIG. 7 is a stress curve diagram of the cantilever beam and the rectangular strain gauge of the acoustic sensor microstructure of the stethoscope according to the present invention.
FIG. 8 is a graph of the harmonic response of the microstructure of the acoustic sensor in the stethoscope according to the present invention.
In the figure: the acoustic sensor comprises a sound pick-up head shell, a 2-polyurethane sound-transmitting cap, a 3-packaging base, a 4-sound sensor microstructure, a 4-1-piezoresistor, a 4-2-rectangular supporting frame, a 4-3-rectangular strain gauge, a 4-4-cantilever beam, a 5-cylindrical connecting pipe, a 6-handheld supporting body, a 7-oil filling hole, an 8-round PCB (printed circuit board), a 9-signal processing circuit board and a 10-power supply.
Detailed description of the invention
The invention is further described below with reference to the accompanying drawings:
as shown in fig. 1 to 4, an electronic stethoscope based on MEMS acoustic sensing principle includes a sound head housing 1, a polyurethane acoustic cap 2, a package base 3, an acoustic sensor microstructure 4, a cylindrical connection tube 5 and a handheld support 6.
The sound head shell 1 is made of aluminum alloy materials, the sound head shell 1 is in a round table shape, the upper end and the lower end of the sound head shell are arranged in an open mode, the upper end is a small open end, the lower end is a large open end, and an oil filling hole 7 is formed in the shell wall of the sound head shell 1.
The polyurethane sound-transmitting cap 2 is bonded and fixed at the large open end of the sound head shell 1 through polyurethane sealant and is used for contacting a human body to conduct heart sound or lung sound; the packaging base 3 is made of aluminum alloy material, and the packaging base 3 is connected with the small opening end of the sound head shell 1 through a thread sealing ring in a threaded mode.
The acoustic sensor microstructure 4 is arranged in the sound head shell 1 and is fixed on the packaging base 3 through a circular PCB 8, and the acoustic sensor microstructure 4 is used for converting heart sounds into electric signals; the acoustic sensor microstructure 4 comprises a rectangular supporting frame 4-2, a rectangular strain gauge 4-3, a cantilever beam 4-4 and a piezoresistor 4-1, wherein the rectangular supporting frame 4-2 is fixed on a circular PCB 8, the rectangular strain gauge 4-3 is suspended at the central position of the rectangular supporting frame 4-2 through the cantilever beam 4-4, four edges of the rectangular strain gauge 4-3 are respectively arranged in parallel with four frame edges of the rectangular supporting frame 4-2, one end of the cantilever beam 4-4 is fixedly connected with the middle position of one edge of the rectangular strain gauge 4-3, the other end of the cantilever beam 4-4 is fixedly connected with the middle position of the frame edge of the corresponding rectangular supporting frame 4-2, and the rectangular strain gauge 4-3 forms a fan-shaped sheet; the number of the piezoresistors 4-1 is four, two of the piezoresistors are distributed on the cantilever beam 4-4, the remaining two piezoresistors are distributed on the frame edge of the rectangular supporting frame 4-2 connected with the cantilever beam 4-4, and the four piezoresistors 4-1 are connected into a Wheatstone bridge; the acoustic sensor microstructure 4 is made of an SOI silicon chip and processed by adopting an MEMS micromachining technology, specifically, a rectangular supporting frame 4-2, a rectangular strain gauge 4-3 and a cantilever beam 4-4 for connecting the rectangular supporting frame 4-2 and the rectangular strain gauge 4-3 are etched on a silicon substrate by utilizing an ICP plasma etching technology, boron ions are respectively injected on the frame sides of the cantilever beam 4-4 and the rectangular supporting frame 4-2 by utilizing a plasma injection technology to form a piezoresistor 4-1, the four piezoresistors 4-1 have equal resistance values and are connected through metal leads to form a Wheatstone differential circuit for detecting cardiopulmonary acoustic signals. When heart sound vibration signals with different intensities are transmitted to the acoustic sensor microstructure 4 in the cavity of the sound head shell 1 through the polyurethane sound-transmitting cap and the silicone oil, the rectangular strain gauge 4-3 is caused to swing and bend up and down, the vibration signals are transmitted to the high-precision cantilever beam 4-4, the stress on the cantilever beam 4-4 changes, the resistance value of the piezoresistor on the corresponding cantilever beam 4-4 changes, and the output voltage value of the Wheatstone bridge also changes synchronously, so that the aim of distinguishing different acoustic signals is fulfilled. According to the acquisition of a period of time and the output voltage value corresponding to the period of time, a heartbeat oscillogram of the heart sound vibration signal can be drawn, and the heart rate parameter can be obtained through calculation.
One end of the cylindrical connecting pipe 5 is connected with the shell wall of the sound head shell 1, the other end of the cylindrical connecting pipe is connected with the handheld supporting body 6, and a lead is arranged in the cylindrical connecting pipe 5 in a penetrating mode.
The handheld support body 6 is made of a plastic material, so that a doctor can conveniently diagnose the physical condition of a patient by using the handheld stethoscope, a signal processing circuit board 9 and a power supply 10 are arranged in the handheld support body 6, the signal processing circuit board 9 is connected with the acoustic sensor microstructure 4 through a lead in the cylindrical connecting pipe 5, and the power supply 10 respectively supplies power to the signal processing circuit board 9 and the acoustic sensor microstructure 4; the signal processing circuit board 9 is arranged at the back position of the handheld supporting body 6, a power supply voltage supply module is arranged on the signal processing circuit board 9, an adjustable stabilized voltage power supply module, a signal conditioning module, a signal acquisition module, a data storage module and a Bluetooth module, wherein the power input end of the power supply voltage supply module is connected with the power supply 10, the power output end of the power supply voltage supply module is connected with the power input end of the adjustable stabilized voltage power supply module, the power output end of the adjustable stabilized voltage power supply module is respectively connected with the signal conditioning module, the signal acquisition module, the data storage module, the Bluetooth module and the power input end of the sound sensor microstructure 4, the signal output end of the sound sensor microstructure 4 is connected with the signal input end of the signal conditioning module, the signal output end of the signal conditioning module is connected with the signal input end of the signal acquisition module, the signal output end of the signal Connecting; the power supply 10 of the power supply voltage supply module regulates the direct current power supply voltage to a corresponding amplitude value through the adjustable voltage-stabilized power supply module, and supplies the regulated direct current power supply voltage to the acoustic sensor microstructure 4 and the signal processing circuit board 9; through signal conditioning module, signal acquisition module's cooperation realizes the enlarged collection to the heart sound signal, at first the signal comes out through signal conditioning module, it handles to signal acquisition module again, then with data signal through the storage of corresponding algorithm processing back to data storage module, also can transmit the data to the cell-phone APP through bluetooth module simultaneously on, bluetooth module passes through signal acquisition module control bluetooth chip, pair with mobile client, realize heart sound and breath sound waveform display and rhythm of the heart digital computation on mobile client APP at last. Meanwhile, due to the action of the amplifying circuit, weak signals are correspondingly amplified, and observation is facilitated. The signal acquisition module is prepared for a storage module and a Bluetooth data transmission module behind by converting analog quantity into digital quantity, the signal acquisition module adopts an stm32 single chip microcomputer which integrates an ADC module, so that the volume occupied by an independent ADC device is reduced, and simultaneously the stm32 single chip microcomputer controls the Bluetooth module to transmit data; the power supply 10 comprises a battery jar arranged on the front surface of the handheld support body 6, a battery is arranged in the battery jar, a battery cover is arranged on the opening of the battery jar, and the power output end of the battery is connected with the power input end of the power supply voltage supplying module.
The inner cavity of the sound head shell 1 is filled with silicone oil with good sound conduction performance through the oil injection hole 7, and the oil injection hole and the lead hole at the joint of the sound head shell 1 and the cylindrical connecting pipe 5 are arranged in a sealing mode.
Fig. 5 is a stress cloud diagram of a simulation of a certain structural dimension of a microstructure of an acoustic sensor in a stethoscope according to the present invention, and fig. 7 is a stress curve diagram on a cantilever beam of the stethoscope according to the corresponding dimension of the microstructure of the acoustic sensor, as can be seen from fig. 5 and 7, which reflects the stress distribution on the cantilever beam, thereby determining the appropriate position for arranging the piezoresistors. Fig. 6 is a first-order mode diagram of the microstructure of the acoustic sensor in the stethoscope according to the present invention, and fig. 8 is a harmonic response curve diagram of the microstructure of the acoustic sensor in the stethoscope according to the present invention, as can be seen from fig. 6 and 8, reflecting the natural frequency of the structure, specifically 4300Hz, the range of the heart sound signal is 20-600Hz, and the natural frequency is greater than this range, which indicates that the frequency band requirement is satisfied and the diagnostic requirement is satisfied.
The above-mentioned embodiments further explain the objects, technical solutions and advantages of the present invention in detail. It should be understood that any modification, equivalent replacement, improvement or the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. The utility model provides an electronic type stethoscope based on MEMS acoustic sensing principle which characterized in that: the acoustic sensor comprises a sound pickup head shell (1), a polyurethane sound-transmitting cap (2), a packaging base (3), an acoustic sensor micro-structure (4), a cylindrical connecting pipe (5) and a handheld supporting body (6); two ends of the sound head shell (1) are open, and an oil filling hole (7) is formed in the shell wall of the sound head shell (1); the polyurethane sound-transmitting cap (2) is packaged at the open end of one end of the sound-pick-up head shell (1), and the packaging base (3) is packaged at the open end of the other end of the sound-pick-up head shell (1); the acoustic sensor microstructure (4) is arranged in the sound pick-up head shell (1) and is fixed on the packaging base (3) through a round PCB (8), the acoustic sensor microstructure (4) comprises a rectangular supporting frame (4-2), a rectangular strain gauge (4-3), a cantilever beam (4-4) and piezoresistors (4-1), the rectangular supporting frame (4-2) is fixed on the round PCB (8), one cantilever beam (4-4) is provided, the rectangular strain gauge (4-3) is suspended at the central position of the rectangular supporting frame (4-2) through the cantilever beam (4-4), one end of the cantilever beam (4-4) is fixed with the rectangular supporting frame (4-2), the other end of the cantilever beam is fixed with the rectangular strain gauge (4-3), the piezoresistors (4-1) are four in total, two of which are distributed on the cantilever beam (4-4), the rest two piezoresistors (4-1) are distributed on the frame edge of the rectangular supporting frame (4-2) connected with the cantilever beam (4-4) to form a Wheatstone bridge; one end of the cylindrical connecting pipe (5) is connected with the shell wall of the sound pick-up head shell (1), the other end of the cylindrical connecting pipe is connected with the handheld support body (6), and a lead is arranged in the cylindrical connecting pipe (5) in a penetrating manner; a signal processing circuit board (9) and a power supply (10) are installed in the handheld supporting body (6), and a power supply voltage supply module, an adjustable voltage-stabilized power supply module, a signal conditioning module, a signal acquisition module, a data storage module and a Bluetooth module are installed on the signal processing circuit board (9); the signal processing circuit board (9) is connected with the acoustic sensor microstructure (4) through a lead in the cylindrical connecting pipe (5), and the power supply (10) supplies power to the signal processing circuit board and the acoustic sensor microstructure (4); the inner cavity of the sound head shell (1) is filled with silicone oil with good sound conduction performance through the oil injection hole (7).
2. The electronic stethoscope based on MEMS acoustic sensing principles of claim 1, wherein: the sound head shell (1) is in a round table shape, the polyurethane sound-transmitting cap (2) is packaged at the large open end of the sound head shell (1), and the packaging base (3) is packaged at the small open end of the sound head shell (1).
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| CN201710553457.9A CN107260206B (en) | 2017-07-08 | 2017-07-08 | Electronic stethoscope based on MEMS (micro-electromechanical systems) sound sensing principle |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109717892A (en) * | 2017-10-27 | 2019-05-07 | 榆林学院 | A kind of MEMS auscultation probe micro-structure based on sonic transducer |
| CN108514428A (en) * | 2018-04-12 | 2018-09-11 | 清华大学 | Gurgling sound harvester |
| CN108735307A (en) * | 2018-05-25 | 2018-11-02 | 山东锋士信息技术有限公司 | A kind of tcm health preserving health care wisdom cloud service system based on big data |
| CN109091135B (en) * | 2018-07-17 | 2021-09-14 | 中北大学 | MEMS technology-based miniature in-situ synchronous heart sound and electrocardiogram detection sensor |
| CN109745068A (en) * | 2019-03-18 | 2019-05-14 | 西安电子科技大学 | A kind of domestic portable fetal heart sound monitoring system |
| CN112957066B (en) * | 2021-02-10 | 2023-04-11 | 中北大学 | Electronic stethoscope based on n-type cantilever beam type one-dimensional MEMS (micro-electromechanical systems) acoustic sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US8024974B2 (en) * | 2005-11-23 | 2011-09-27 | 3M Innovative Properties Company | Cantilevered bioacoustic sensor and method using same |
| WO2011034843A1 (en) * | 2009-09-16 | 2011-03-24 | 3M Innovative Properties Company | Electronic stethoscope system for telemedicine applications |
| CN204520758U (en) * | 2015-03-21 | 2015-08-05 | 孙巧玲 | Teaching stethoscope |
| CN204734501U (en) * | 2015-06-10 | 2015-11-04 | 章哲华 | Teaching stethoscope |
| CN105232080B (en) * | 2015-09-17 | 2017-10-31 | 中北大学 | Visualization electronic type stethoscope based on MEMS sonic transducers |
| CN106236130A (en) * | 2016-08-30 | 2016-12-21 | 苏州中盛纳米科技有限公司 | A kind of electronic type stethoscope based on MEMS technology |
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