CN101700186A - Bluetooth Electronic Heart Sound Stethoscope - Google Patents

Abstract

The invention discloses a bluetooth electronic cardiophone which is characterized by comprising a portable terminal and a PC. In the portable terminal, after a sensor conducts primary amplifying, lowpass filtering and secondary amplifying on an acquired cardiac sound signal, a power amplification module conducts real-time cardiac sound playing on one path of the cardiac sound signal, and after a master control module conducts A/D conversion on the other path of the cardiac sound signal, a liquid crystal screen displays a phonocardiogram at the real time, and the other path of the cardiac sound signal is transmitted to the PC by a serial port or a bluetooth transmission module; and the PC displays the phonocardiogram at the real time through a PC screen after received cardiac data is processed by the master control module at the PC end, or the received cardiac data is stored by a storage module and assists a diagnosis module to carry out computer assisted diagnosis according to requires. Compared with the prior art, the invention has the advantages of storing and analyzing the cardiac sound data, displaying the phonocardiogram at the real time, providing more intuitive diagnosis data and giving prompts to common heart diseases, such as tachycardia, bradycardia, arrhythmia, and the like.

Description

Bluetooth Electronic Heart Sound Stethoscope

technical field

The invention relates to the technical field of computer diagnosis and medical treatment, in particular to a bluetooth electronic heart sound stethoscope.

Background technique

Doctors usually use a traditional mechanical stethoscope when seeing a patient. The mechanical stethoscope is composed of a listening head, a rubber tube, a metal frame, and earplugs. The heart sound is vibrated through the diaphragm of the listening head, and the heart sound is transmitted to the earplugs by the connected rubber tube. , due to structural limitations, the traditional stethoscope can only be used by one person, and the transmission distance is greatly limited.

Now some electronic stethoscopes have also been developed, which have made some progress on the basis of traditional stethoscopes. The heart sound signal can be amplified and processed through the stethoscope head. (Patent No. 02144276.2) and "Medical Electronic Stethoscope" (Patent No. 200520069536.5) both have a certain signal preprocessing function, which can improve the precision and accuracy of the enhanced signal, but cannot transmit, record or analyze the acquired signal. "Remote Electronic Stethoscope" (Patent No. 03241337.8) and "Wireless Electronic Stethoscope" (Patent No. 200410012647.2) have improved the stethoscope signal transmission function to a certain extent. "Wireless Electronic Stethoscope" (Patent No. 200720119416.0) has recording and playback functions. However, these electronic stethoscopes all lack digitization of acquired signals and computer-aided diagnosis of the signals.

Contents of the invention

The purpose of the present invention is to provide a bluetooth electronic heart sound stethoscope for the deficiencies in the prior art. Its portable terminal can amplify and filter the patient's heart sound signal, and can play it in real time through the loudspeaker after power amplification. After sampling by the processor, the LCD screen displays the phonocardiogram, which is transmitted to the PC through the serial port or bluetooth to display the phonocardiogram and heart rate in real time, and the collected signal is analyzed by computer to detect common symptoms of tachycardia, arrhythmia and heart valves. Diseases give diagnostic hints.

The concrete technical scheme that realizes the object of the present invention is: a kind of bluetooth electronic heart sound stethoscope, it is characterized in that this stethoscope is made up of portable terminal machine and PC machine, and the heart sound signal that portable terminal machine will gather by sensor is through primary amplification, low-pass filter, secondary After the stage is amplified, it is divided into two outputs, one is routed to the power amplifier module for real-time heart sound playback, and the other is routed to the main control module to A/D convert the heart sound signal and display the real-time phonocardiogram on the LCD screen, and transmit it to the PC through the serial port or Bluetooth sending module The PC will display the phonocardiogram in real time on the PC screen after the heart sound data received by the PC is processed by the main control module of the PC, or the data storage by the storage module and the computer-aided diagnosis by the auxiliary diagnosis module as required.

The primary amplification and secondary amplification adopt JRC4558D operational amplifier chip, and the amplification factor can be adjusted to adapt to the amplitude of different detection objects.

The low-pass filter uses a MAX7410 fifth-order Butterworth filter chip.

The main control module is an S3C2410 embedded processor.

The PC-side main control module can store the phonocardiogram data as a file or export it into a WAV audio format to be played by a compatible player.

The auxiliary diagnosis module is a computer-aided diagnosis for common tachycardia, arrhythmia and heart valve diseases by PC terminal software according to the phonocardiogram, and gives corresponding prompts.

The device of the present invention is simple and easy to use, and has the following beneficial effects compared with the prior art:

(1) It can amplify the heart sound signal, and the speaker can play it in real time, without wearing a stethoscope earpiece or earphones, and can also connect external speakers through the audio interface, and use ordinary earphones for auscultation;

(2) The magnification can be adjusted to obtain good results for signals from different patients;

(3) The LCD screen or PC of the portable terminal can display the phonocardiogram in real time, providing doctors with more intuitive diagnostic data;

(4) It can be transmitted to PC through Bluetooth wireless transmission or serial port, which is convenient for the storage and analysis of digital signals;

(5) The software of the PC terminal can save the heart sound data within the selected time range, including two kinds of phonocardiogram data format and WAV audio format, and can convert each other;

(6) Computer-aided diagnosis based on heart sound signals, real-time detection of heart rate, and diagnosis prompts for common heart diseases such as tachycardia, bradycardia, and arrhythmia;

(7) Power supply in multiple ways. The portable terminal can be powered by DC power supply and rechargeable battery. The device can be plugged into the DC power supply to charge the battery, so as to achieve the purpose of repeated use of the battery.

Description of drawings

Fig. 1 is a structural representation of the present invention

Figure 2 is the primary amplifier circuit diagram

Figure 3 is a low-pass filter circuit diagram

Figure 4 is a secondary amplifier circuit diagram

Figure 5 is a power amplifier circuit diagram

Figure 6 is the main control module and connection circuit diagram

Figure 7 is a flow chart of Bluetooth transmission

Figure 8 is a bluetooth packet format diagram

Figure 9 is the PC program interface and heart sound waveform diagram

Figure 10 is a diagram of S1, S2 detection and heart rate detection

Detailed ways

Referring to accompanying drawing 1, the present invention is made up of portable terminal machine 1 and PC machine 2, portable terminal machine 1 comprises: sensor 3, primary amplifier 4, low-pass filter 5, secondary amplifier 6, main control module 7, power amplifier module 8, LCD screen 9, bluetooth sending module 10 and serial port 11; PC machine 2 comprises: bluetooth receiving module 12, serial port 13, PC end main control module 14, storage module 15, auxiliary diagnosis module 16 and PC screen 17, sensor 3 will collect The heart sound signal is divided into two outputs after primary amplification 4, low-pass filter 5, and secondary amplification 6. One is routed to the power amplifier module 8 for real-time heart sound playback, and the other is routed to the main control module 7 to A/D convert the heart sound signal to the LCD screen. 9. Carry out real-time phonocardiogram display, and transmit the heart sound signal to the PC 2 through the serial port 11 or the Bluetooth sending module 10, and the heart sound data received by the serial port 13 or the Bluetooth receiving module 12 will be processed by the PC end main control module 14 program control and processed by the PC The screen 17 displays the phonocardiogram in real time, or the storage module 15 performs data storage and the auxiliary diagnosis module 16 performs computer-aided diagnosis as required, and gives corresponding prompts.

Below in conjunction with specific embodiment technical scheme of the present invention is described in further detail, and its concrete steps are as follows:

(1) Primary amplification of heart sound signal

Referring to accompanying drawing 2, the primary amplifier 4 is the circuit of the JRC 4558D operational amplifier chip, the heart sound signal collected from the sensor 3 is amplified by the signal of the primary amplifier 4, and the capacitor C1 plays the role of blocking and coupling the AC signal. Since the JRC 4558D uses a single power supply, the input signal must be DC biased to establish a static operating point, so after C1, the resistor R1 and resistor R2 are used to bias the signal at 2.5V DC, and the resistor R1 and resistor R2 are adjusted. The value of the upper and lower swings tends to be consistent. The resistor R5, the resistor R6, the capacitor C8, and the capacitor C6 constitute an amplification branch of the operational amplifier. The function of capacitor C8 and capacitor C6 is to make the circuit only amplify the AC signal and not amplify the DC signal. Changing the resistance value of resistor R5 can change the magnification of the circuit. The magnification A of the circuit can refer to the following formula:

$\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 6</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 5</span>}}$

(2) Low-pass filtering of heart sound signal

Referring to accompanying drawing 3, the low-pass filter 5 is the circuit of the MAX7410 fifth-order Butterworth filter chip, which can obtain a more accurate cut-off frequency and a higher order to suppress or attenuate the high frequency from the 20-600Hz heart sound signal noise. When using the chip's internal clock, a ground-connected capacitor is required, and its frequency calculation formula is:

f _OSC (kHz)＝30*10 ³ /C _OSC (pF)

The relationship between filter cutoff frequency and clock frequency:

f _C = f _CLK /100

Among them: f _CLK =f _OSC , from f _C =600Hz, get C _OSC =500pF.

(3) Secondary amplification of the heart sound signal

Referring to accompanying drawings 4 and 5, the circuit of the secondary amplifier 6 is basically the same as that of the primary amplifier 4, but there is no need to set a DC blocking capacitor and a bias resistor for the input, wherein the resistor R7 is adjustable for adjusting the magnification. The heart sound signal is provided with two-way output after secondary amplification 6, and one output is connected with the power amplifier module 8 that is provided with loudspeaker and audio output interface to play in real time, and the other output is connected with the main control module 7, because the operating voltage of the main control module 7 is 3.3V, so the static operating point needs to be reset.

(4) Settings of the main control module

Referring to accompanying drawing 6, the heart sound signal that collects is through primary amplification 4, low-pass filter 5, the heart sound signal preprocessed by secondary amplification 6 outputs one way and connects the power amplifier module 8 that is provided with loudspeaker and audio output interface to play in real time, and another way outputs Connect the main control module 7, the main control module 7 adopts S3C2410 ARM embedded processor, 3.3V power supply. The filtered and amplified heart sound signal is input to the A/D sampling terminal (AIN2 pin) of S3C2410 for 1K Hz sampling, and the S3C2410 processor is connected to the LCD screen through VD0~VD23 and other pins.

The program of main control module 7 comprises: system clock, operating mode, input, the initialization of output interface, UART initialization, A/D sampling, signal processing, timing control, liquid crystal display, bluetooth module initialisation, bluetooth inquiry, establish connection, data Transmit, disconnect, and error responses.

The bluetooth transmission data designed by the main control module 7 is packaged and sent every 5 samples, and sent every 5ms, and is controlled by timer TOUT0 of S3C2410 in an interrupt mode.

(5) Transmission of heart sound data

Referring to accompanying drawing 7, the heart sound signal processed by main control module 7 is transmitted to PC 2 with serial port 11 or bluetooth sending module 10, serial port 13 or bluetooth receiving module 12, and serial port 11,13 adopts RS232 serial transmission, and bluetooth sending module 11 , bluetooth receiving module 12 adopts the BlueCore4-Rom chip that CSR company produces, and is connected with main control module 7 by UART, and main control module 7 is sent each by bluetooth main controller interface (HCI) to bluetooth main controller by hci_send_cmd () function commands and receive events returned by the master. HCI commands are sent to the main controller in the form of data packets.

The format of the data packet is instruction operation code (OGF, OCF), data length and specific command data. When UART (H4) is transmitted, a byte of HCI indication packet should be added in front to distinguish what kind of HCI packet it is. After most commands are executed, they will return a successful command execution event (Command Complete event) in the form of an event group. For specific parameters, please refer to the Bluetooth specification.

The entire HCI communication process mainly includes: Bluetooth module initialization; Bluetooth master device query; connection establishment steps. After completing the A/D sampling of the heart sound data, add the packet header information required for Bluetooth transmission before the data, and then send it to the slave device through the master controller.

Referring to accompanying drawing 8, bluetooth packet format, packet head comprises connection handle, PB, BC sign (packet demarcation sign, data broadcast sign) and data length. The actual form of the packet header is (hexadecimal): 022A200100, a total of 5 bytes, of which 02 means ACL data packet; 2A 20 is the connection handle and PB, BC signs, the connection handle occupies the lower 12 bits of the 2 bytes, in After the connection is successfully established, it will be automatically assigned by the Bluetooth module, and the sending end must be consistent with the receiving end, here is 0x002A; BC, PB (0b0010) means the use of point-to-point connection and single data mode; 0500 means that the subsequent data is 5 characters Section, that is, five 8-bit A/D sampling valid data. The PC main control 14 of the receiving PC 2 mainly completes the initialization of the Bluetooth receiving module 12, implementation of the HCI Bluetooth upper layer protocol, timing control, and data reception.

(6) Display of heart sound waveform

Referring to accompanying drawing 9, the sampling frequency of heart sound data is 1000Hz. On the liquid crystal screen 9 of portable terminal 1, data is drawn once on the screen every 5ms, and each time (period) depicts 5 points, and the work is as follows: first the heart sound waveform of the whole screen is moved to the right by one pixel (screen at the beginning is empty), draw the 5 data just received on the first column that has been vacated (according to the amplitude plot). The 5 points in the first column are connected, and the first received data in the first column is connected with the last drawn point in the second column to realize the continuity of the waveform graph. Such fast repetition is to realize the dynamic oscilloscope of the LCD screen 9 of the portable terminal 1. The LCD screen 9 display selects the L35T32 LCD screen, and the circuit connection with the main control module 7 is referred to accompanying drawing 6.

The PC 2 receives the heart sound data through the serial port 13 or the Bluetooth receiving module 12 , and the PC main control module 14 performs real-time heart sound dynamic oscillography on the PC screen 17 after the received digital heart sound data is graphically displayed. The Bluetooth transmission of the above-mentioned portable terminal 1 also transmits 5 sampling data at a time, and uses the high-precision timer of the S3C2410 to send a data packet every 5ms. The receiving end of PC 2 also receives data once every 5ms. The oscillometric algorithm is similar to that of portable terminal 1. In each cycle, the entire waveform is first shifted to the right by one pixel, and 5 newly received points are drawn in the first column. The fast cycle repeats, so that the dynamic oscilloscope of the PC screen 17 is realized.

(7) Access to heart sound data

The storage module 15 of the PC 2 can intercept and save heart sound data within a specified time range for the user for further analysis and diagnosis. There are two formats of data storage: phonocardiogram data format and WAV audio format. The user can also use the storage module 15 to restore the saved phonocardiogram data files and WAV audio files into waveform diagrams or play them.

The suffix of the phonocardiogram data file is .txt, which adopts PCM encoding, and each line has an integer, which directly corresponds to the quantized digital quantity of the analog sound wave. The data sampling rate is 1000Hz, 1Byte (8bit), and the value range is -128～127.

The user can use the storage module 15 to export the phonocardiogram data into a WAV audio format to be played by a compatible player as required. WAV is a sound file format developed by Microsoft (Microsoft), also known as PCM (Pulse Code Modulation) sound file, which is an uncompressed sound wave data file. The data directly corresponds to the quantized digital quantity of the analog sound wave. Each quantization The value is 1Byte (8bit), and the value range is 0~255.

(8) Computer-aided diagnosis

Referring to accompanying drawing 10, the auxiliary diagnosis module 16 utilizes the analysis signal-heart sound envelope obtained by Hilbert-Huang transformation to obtain the phonocardiogram data, and by setting a suitable threshold, utilizes the differential method to segment the envelope to obtain the first Heart sound, the position of the second heart sound (start point, highest point, end point), combined with the sampling frequency to calculate the heart rate. In addition, according to the duration of heart sounds S1 and S2 and the noise waveforms in the picture, medical tips are given for common diseases such as tachycardia, bradycardia and arrhythmia.

The above is only a further description of the present invention, and is not intended to limit the patent, and all equivalent implementations of the present invention should be included in the scope of claims of the patent.

Claims (6)

1. Bluetooth electronic cardiophone, it is characterized in that this stethoscope is made up of mobile terminal device and PC, mobile terminal device by pick off with the cardiechema signals gathered through elementary amplification, low-pass filtering, secondary amplifies the back and divides two-way output, one route power amplifier module carries out real-time hear sounds and plays, another route main control module carries out real-time phonocardiogram with cardiechema signals A/D conversion back by liquid crystal display screen and shows, and being transferred to PC by serial ports or bluetooth sending module, PC is handled the back by PC screen demonstration phonocardiogram or carry out data storage by memory module as required and the auxiliary diagnosis module is carried out computer-aided diagnosis in real time with the heart sound data that receives through PC end main control module.

2. according to the described Bluetooth electronic cardiophone of claim 1, it is characterized in that described elementary amplification and secondary amplify employing JRC4558D computing and amplify chip, and the scalable amplification is to adapt to the amplitude of different detected objects.

3. according to the described Bluetooth electronic cardiophone of claim 1, it is characterized in that described low-pass filtering adopts MAX7410 five rank Butterworth filtering chips.

4. according to the described Bluetooth electronic cardiophone of claim 1, it is characterized in that described main control module is the S3C2410 flush bonding processor.

5. according to the described Bluetooth electronic cardiophone of claim 1, it is characterized in that described PC end main control module can become the phonocardiogram data storage file or export to the WAV audio format with compatible player plays.

6. according to the described Bluetooth electronic cardiophone of claim 1, it is characterized in that described auxiliary diagnosis module is that the PC terminal software is slow excessively to common tachycardia according to phonocardiogram, arrhythmia and valvular heart disease carry out computer-aided diagnosis, and provide corresponding prompting.

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