CN201033074Y - Portable ECG Wireless Monitor - Google Patents

Abstract

The utility model is a portable electrocardiogram wireless monitor, which belongs to the technical field of research and development of electronic medical instruments. It mainly includes an ECG acquisition module (1), an amplification and filtering processing module (2), a microcontroller (3), a keyboard (6) and a GPRS wireless module (7), and the amplification and filtering processing module (2) combines the ECG acquisition module ( 1) The collected ECG signal is amplified and filtered and sent to the microcontroller (3), and the keyboard (6) controls the microcontroller (3) to start collecting the ECG signal, and the ECG signal is checked once every 2 to 5 seconds. ECG detection analysis, if the electrocardiogram is abnormal, the buzzer (8) sounds, if the alarm of the buzzer (8) is not touched within 6 to 10 seconds, the microcontroller will send the alarm through the GPRS wireless alarm module (7) Send a short message to the monitoring terminal. The utility model adopts a single-chip microcomputer and a GPRS wireless module to carry out an alarm, so that the monitor has the advantages of small size, low power consumption, stable and reliable operation, and the like.

Description

Portable ECG Wireless Monitor

technical field

The utility model is a portable electrocardiogram wireless monitor, which belongs to the technical field of research and development of electronic medical instruments.

Background technique

As we all know, cardiovascular disease is already the number one killer threatening human life and health. According to the WHO report, 17.5 million people die from cardiovascular disease every year, and cardiovascular disease is the first cause of death, accounting for about 30% of deaths from various causes. It is estimated that by 2020, 25 million patients will die from cardiovascular diseases. In my country, the prevalence, morbidity and mortality of cardiovascular diseases are also on the rise, and the death toll accounts for about 40% of the total death toll. Heart disease has the characteristics of sudden, unpredictable, and high mortality, so it is particularly important to monitor patients' ECG signals in real time. At present, due to factors such as changes in people's lifestyles and fierce social competition, the incidence of cardiovascular diseases continues to rise, and has a trend of younger age. Most patients need instruments that can provide ECG monitoring at any time, and make them work and live. will not be affected. Most of the current ECG monitors are expensive and complicated to operate, so they are not suitable for popularization in families; due to the use of wired communication methods, they can only be used in fixed environments or small ranges of activities, and cannot achieve the purpose of dynamic monitoring.

Utility model content

The purpose of the utility model is to develop a portable ECG wireless monitor for families, which can collect, analyze and alarm in real time. It can monitor and analyze the ECG signal in real time through the portable instrument worn, and give a diagnosis and alarm to the arrhythmia. Short messages to gain valuable treatment time.

In order to achieve the above object, the utility model adopts the following technical solutions. It mainly includes an ECG acquisition module 1, an amplification and filtering processing module 2, a microcontroller 3, a liquid crystal display module 4, and a power supply module 5. The amplification and filtering processing module 2 amplifies and filters the ECG signals collected by the ECG acquisition module 1 and sends them to the Into the microcontroller 3, which is characterized in that: it also includes a keyboard 6 and a GPRS wireless module 7 connected to the microcontroller 3, the keyboard 6 can control the microcontroller 3 to start collecting ECG signals, and every 2 to 5 seconds An ECG detection analysis is performed on the ECG signal, and the heart rate obtained by the ECG detection is sent to the liquid crystal display module 4 for display. If the ECG is abnormal (such as the heart rate is too fast or too slow), the buzzer 8 will sound, and the keyboard 6 can be disconnected. The connection of the buzzer and the microcontroller 3, if the buzzer 8 is not disconnected with the microcontroller 3 within 6 to 10 seconds, the microcontroller will send a short message to the monitoring terminal through the GPRS wireless alarm module 7.

Described keyboard 6 comprises four buttons S1, S2, S3, S4 that are connected with the input and output ports of microcontroller 3, the press of button S2 can control microcontroller 3 to start collecting electrocardiogram signal, button S3 can Adjust its amplitude according to the ECG signal waveform displayed by the liquid crystal display module 4. Press the button S4 to make the microcontroller 3 perform ECG detection on the ECG signal every 2 to 5 seconds. When the buzzer sounds, press Press the confirmation key S1 to confirm that the ECG signal is not really abnormal, and the buzzer is disconnected from the single-chip microcomputer through software setting to cancel the alarm.

Described microcontroller 3 is 16 single-chip microcomputers MSP430.

The instrument can be powered by a lithium battery or an AC power supply, and the input voltage is converted to the required voltage through the power circuit.

The utility model adopts a 16-bit single-chip microcomputer MSP430 with ultra-low power consumption as the system kernel and a GPRS wireless module for alarming, so that the monitor has the advantages of small size, low power consumption, stable and reliable operation, and the like. The monitor has low cost and is easy to carry, which greatly improves the application range of the ECG monitor.

Description of drawings

Figure 1: System flow chart;

Figure 2: Block diagram of the principle structure of the ECG wireless monitor system

Figure 3: Structural diagram of ECG signal amplification and filtering circuit

Figure 4: Circuit diagram of the digital part of the monitor

Figure 5: Power Circuit Diagram

Figure 6: Pulse signal amplification and filtering circuit diagram

Detailed ways

This embodiment will be described in detail below with reference to FIGS. 1 to 6 .

This embodiment mainly includes an ECG acquisition module 1, an amplification and filtering processing module 2, a microcontroller 3, a liquid crystal display module 4, a power supply module 5, a keyboard 6, and a GPRS wireless module 7, and the keyboard 6 includes an input with the microcontroller 3. The four buttons S1, S2, S3, and S4 connected to the output port. Wherein, the amplification and filtering processing module 2 amplifies and filters the ECG signals collected by the ECG acquisition module 1 and sends them to the microcontroller 3 . The keyboard 6 can control the microcontroller 3 to collect ECG signals, and conduct ECG detection and analysis on the collected results to obtain the real-time heart rate. If the heart rate is normal, an alarm will be issued. If the alarm is not released within 10s, the GPRS wireless alarm will be activated. The module sends a short message to the monitoring terminal.

The portable family ECG wireless monitor of this embodiment uses the ultra-low power consumption 16-bit single-chip MSP430F449 of Texas Instruments as the control core. The MSP430F449 single-chip has a built-in eight-channel 12-bit A/D converter, so no additional ADC chip is required. , At the same time, it also contains two general-purpose synchronous/asynchronous serial communication interfaces, which makes the design of the interface circuit simpler, the integration level is higher, the volume of the instrument is greatly reduced, and the portability of the monitor is enhanced.

The communication mode of the ECG wireless monitor in this embodiment adopts the GPRS wireless module, communicates through the existing and mature GSM network, and can be applied wherever the GSM network covers. Therefore, the range of activities of the patient is expanded, and the quality of life of the patient is improved. In this monitor, the wireless communication module adopts the GSM/GPRS wireless module MC55 of Siemens, which is the smallest tri-frequency module in the market today, and its compact design is especially suitable for portable devices. The module has small size (5.5g), low power consumption (peak current 450mA), simple control, built-in AT command set, TCP/IP protocol. Under the control of the single-chip microcomputer, the existing GSM network is used for signal processing and transmission, so as to realize the purpose of remote wireless monitoring. The MC55 module can quickly and reliably realize wireless communication functions such as data and voice transmission, short message and fax services. It provides a 50-pin zero insertion (ZIF) connector, which includes several sub-interfaces such as power interface, serial interface, audio interface, and SIM card interface. connected to the main controller.

The circuit diagram of the digital part of the ECG monitor of the present utility model is shown in Figure 4. The keyboard is an input device for man-machine dialogue. With the help of the keyboard, parameters can be set to the system and control commands can be issued. When scanning the keyboard, first determine which column the button is located in according to which port line input value is not 1 among P1.4, P1.5, P1.6, and P1.7 of the read P1 port, and then detect P1.3 Is the value of 1, because only 4 buttons are used in the design and are in the same row, so if the value of P1.3 is 1, it means that the button is the button in this column, so as to determine the position of the button and perform the corresponding operation. Among them, S1 is a confirmation key, S2 is a selection key, S3 is a waveform adjustment key, and S4 is a detection key. When performing ECG wireless monitoring, first obtain ECG signals from the human body through the electrodes, send them to the pre-amplification filter, and then enter the single-chip microcomputer after being amplified and filtered by the analog amplifier circuit. After pressing the confirmation key S1, the LCD module will The menu interface is displayed. At this time, you can press the acquisition key S2 to select the acquisition of ECG signals, and then press the confirmation key S1, then use the ADC12 conversion module inside the microcontroller to perform analog-to-digital conversion on the analog signal, and send the acquired waveform to the LCD. displayed on the monitor. Due to individual differences, the size of the waveform can be adjusted through S3 according to the amplitude of the displayed ECG signal. After the waveform is stable, press the detection button S4 to perform an ECG detection analysis every 3s to obtain and display the real-time heart rate. Thereby it is judged whether the heart rate is abnormal, if the abnormal electrocardiogram is produced, report to the police immediately, if the confirmation key S1 is not pressed within 8 seconds to release the alarm, start the GPRS wireless alarm module to send a short message to the monitoring terminal.

As shown in Figure 4, J_LCD is the LCD display interface socket, and the dot-matrix liquid crystal display can display various graphic information, Chinese characters, etc. in addition to displaying characters. The liquid crystal display module 4 in this embodiment adopts RT12864CT dot-matrix liquid crystal Display, liquid crystal display RT12864CT is a 128×64 dot matrix display module with EL backlight, which can display graphics and text.

As shown in Figure 4, U6 is the RS232 serial interface chip MAX3232, and J2 is the serial interface socket, which can communicate with the MC55 wireless module through this serial interface. Since the signal level of MSP430 is only 3.3V, the 3.3V logic level conversion chip MAX3232 newly launched by MAXIM is selected to complete the level conversion, and convert the CMOS voltage serially output by MSP430 into a standard RS-232-C logic voltage. flat. JTAG is the JTAG adjustment interface socket, which is connected to the PC through this socket to realize online debugging and downloading of the program.

In order to make the monitor easy to carry, the developed ECG wireless monitor can be powered by +3.7V lithium battery. Since the MSP430 single-chip microcomputer and the corresponding digital parts use low level, it needs to be designed to be powered by +3.3V power supply, and the monitoring system The operational amplifiers used in the analog parts such as the mid-amplification filter circuit are powered by ±5V power supply. Therefore, we need to convert the power supply voltage into +3.3V, +5V and -5V to supply the MSP430 microcontroller and its analog and digital circuit parts. The power supply circuit is shown in Fig. 5, mainly adopts the power management chip LTC3441 and LT1613 of Linear Technology Company and the product MAX860 of MAXIM Company. The LTC3441 is a high efficiency, fixed frequency buck-boost DC/DC converter that operates efficiently from input voltages above, below or equal to the output voltage. Quiescent current of only 25µA matches the system's low power design, making it ideal for single-cell Li-Ion or multi-cell applications where the output voltage is within the battery voltage range. Burst Mode operation is under user control and can be enabled by driving the MODE/SYNC pin high. Fixed frequency switching is enabled if the MODE/SYNC pin is driven low or has a clock. The typical working circuit of LTC3441 is shown in Fig. 5, the input voltage is +3.7V, the output voltage is +3.3V. The LT1613 is the industry's first current mode DC/DC converter in a 5-lead SOT-23 package. Targeted at small, low-power applications, it operates from an input voltage as low as 1.1V and switches at 1.4MHz. Thanks to its small size and high switching frequency, users require less than 0.2 square inches of printed circuit board area A complete DC/DC converter function can be realized. The device is capable of generating 5V and 200mA from a 3.3V supply, or 5V and 175mA from four alkaline cells. The typical working circuit of LT1613 is shown in Figure 5, the input voltage is +3.3V, and the output voltage is +5V. MAX860 can convert the voltage input range from +1.5V to +5.5V to the corresponding negative voltage (ie -5.5V to -1.5V), or convert the voltage input range from +2.5V to +5.5V In order to double the output, its function of outputting negative voltage is applied in this design, that is, the voltage of +5V is converted into -5V.

The electrocardiographic signal amplification and filtering circuit is shown in Figure 6, which is composed of a preamplifier circuit, a main amplifier circuit, a bandpass filter, a level boost circuit and a limiter circuit. The circuit uses two 14-pin IC chips TL084, one 8-pin IC chip AD620 and one 20-pin band-pass filter chip MAX275. The voltage amplitude of the electrocardiographic signal extracted from the sensor is only a few millivolts. Therefore, according to the characteristics of the electrocardiographic signal and design requirements, it is usually required that the electrocardiographic amplifier should have an amplification factor of hundreds to thousands of times. In this design, the first stage of the ECG amplifier circuit adopts the high-performance operational amplifier AD620 of AD Company, which is a low-power, high-precision instrumentation amplifier that can set the magnification from 1 to 1000 with only one external resistor. Wide power supply range (±2.3V～±18V), small design size, very low power consumption (maximum supply current is only 1.3mA), so it is very suitable for sensor interface, ECG monitor, precision voltage-current conversion and other low-voltage, Low power consumption occasions. At the same time, the ECG signal is susceptible to high-frequency interference and 50Hz mains interference, so a 0.05-100Hz band-pass filter and a 50Hz notch circuit are used in the circuit to eliminate 50Hz power frequency interference and suppress other high-frequency noise. Since the collected ECG signals are bipolar signals, and the A/D module inside the MSP430 microcontroller can only convert unipolar signals, the level of the analog signal must be raised to make its waveform in the positive range, so Design a level-boosting circuit to boost the voltage of the analog ECG signal. At the same time, in order to keep the ECG signal from exceeding the reference voltage range of the A/D module, a limiting circuit needs to be designed to limit the dynamic voltage range of the analog signal.

Using this monitor we carry out the following tests. After turning on the power, the welcome interface will appear first, indicating that the instrument is working normally. Extract various ECG signals from the generator. After pressing the confirmation key S1, the LCD will display whether to collect ECG signals. At this time, you can press the acquisition key S2, and then use the ADC12 conversion module inside the microcontroller to simulate the analog signal. Digital conversion, and the collected waveforms are sent to the liquid crystal display for display. Due to the different conditions of each human body, the amplitude of the ECG signal may be different. Therefore, the amplitude of the displayed waveform can be adjusted by adjusting the button S3 to achieve the best waveform. After the waveform has been adjusted and stabilized, press the detection key S4 to conduct an ECG detection analysis every once in a while (about 3s), get the real-time heart rate and display it, so as to judge whether the heart rate is abnormal, and immediately call the police if there is an abnormal ECG , if the confirmation key S1 cannot be pressed to release the alarm within a certain period of time, start the GPRS wireless alarm module to send a short message to the monitoring terminal.

After the experiment is completed, the test results are compared with the actual parameters of the ECG waveform generated by the ECG signal generator, and the results are shown in Table 1. It can be seen that the heart rate parameters of the detection results are basically consistent with the actual ECG signal parameters, which reflects the accuracy of the system.

The test results show that the ECG monitor is easy to operate, works stably, and can monitor and alarm ECG signals in real time.

Table 1 Comparison of test results

Claims (3)

1. portable cardiac wireless monitoring instrument, mainly include electrocardiogram acquisition module (1), amplification filtering processing module (2), microcontroller (3), LCD MODULE (4), power module (5), amplification filtering processing module (2) is amplified the electrocardiosignal that electrocardiogram acquisition module (1) collects, send into microcontroller (3) after the filtering, it is characterized in that: also include the keyboard (6) and the GPRS wireless module (7) that are connected with microcontroller (3), keyboard (6) can be controlled microcontroller (3) and begin to gather electrocardiosignal, and every 2～5 seconds electrocardiosignal is carried out an ECG detection and analyze, the heart rate that the ECG detection draws is delivered to LCD MODULE (4) and is shown, if anomalous ecg, buzzer (8) sounds, can disconnect being connected of buzzer and microcontroller (3) by keyboard (6), if buzzer (8) does not disconnect with microcontroller (3) and being connected in 6～10 seconds, microcontroller will send SMS message to monitoring terminal by GPRS radio alarming module (7).

2. portable cardiac wireless monitoring instrument according to claim 1, it is characterized in that: described keyboard (6) includes the S1 that is connected with the input/output port of microcontroller (3), S2, S3, four buttons of S4, the may command microcontroller (3) of pressing of button S2 begins to gather electrocardiosignal, button S3 can adjust its amplitude according to the shown electrocardiosignal waveform of LCD MODULE (4), button S4 presses and makes microcontroller (3) carry out an ECG detection every 2～5 seconds to electrocardiosignal, when buzzer sounded, the pressing of button S1 can disconnect being connected of buzzer and microcontroller (3).

3. portable cardiac wireless monitoring instrument according to claim 1 is characterized in that: described microcontroller (3) is 16 single-chip microcomputer MSP430.

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