KR20080088247A - Wireless biomedical signal monitoring device on movable vehicle using noncontact electro-mechanical film sensor - Google Patents

Abstract

A wireless biomedical signal monitoring device on a movable vehicle using a noncontact electro-mechanical film sensor is provided to use a 3-axial acceleration sensor to remove a movement signal influencing on a BCG(BallistoCardioGraph) signal. A wireless biomedical signal monitoring device on a movable vehicle includes a sensing sheet, a transmitter(14), a receiver(21), a server, and a computer. The sensing sheet includes a noncontact electro-mechanical film sensor and is positioned on a sheet of the movable vehicle. The transmitter detects a heartbeat signal and a respiration signal from a BCG from the sensing sheet and transmits the heartbeat signal and the respiration signal through a wireless communication channel. The receiver receives the heartbeat signal and the respiration signal and transmits the received signals to a mobile communication terminal(31) through a cable. The server analyzes the signals received from the mobile communication terminal through mobile communication network. The computer is connected to the server.

Description

Wireless Biomedical Signal Monitoring Device on Movable Vehicle using Noncontact Electro-mechanical Film Sensor}

1 is a perspective view showing a moving body and a transmitter according to an embodiment of the present invention.

2 illustrates a transmitter, a receiver, and a mobile terminal according to an embodiment of the present invention.

3 is a view showing the appearance of a receiver and a mobile communication terminal according to an embodiment of the present invention;

4 is a view showing a wireless bio-signal monitoring apparatus for a moving body according to an embodiment of the present invention.

5 is a graph showing 19 breaths for 1 minute using SKpac sensor of Biopac.

6 is a graph showing the BCG original signal detected through the sensing sheet in the experiment.

7 is a graph showing the respiration signal detected through a Gaussian filter in the BCG original signal of FIG. 6.

8 is a graph showing the respiratory signal obtained from the subject in the experiment applying hypothesis 1 of the tine-driven manual wheelchair.

Figure 9 is a graph showing the results of 20 breaths for 50 seconds according to hypothesis 2.

10 is a graph showing the results of breathing 17 times for 1 minute according to hypothesis 3.

11 is a graph showing signals generated when adjusting a wheelchair.

12 is a graph showing a signal obtained from a three-axis acceleration sensor.

FIG. 13 is a graph showing a result of calibrating a BCG signal using a three-axis acceleration sensor. FIG.

<Description of Symbols for Main Parts of Drawings>

10: moving body 11: non-contact piezoelectric sensor

12: sensing sheet 13: cable

14 transmitter 21 receiver

31: mobile communication terminal 41: remote server

42: computer

The present invention relates to a monitoring device for monitoring the human heart rate and respiratory rate in real time, and in particular, to monitor the heart rate and respiratory rate in real time during the movement of the patient using a noncontact electro-mechanical film sensor. It relates to a wireless bio-signal monitoring device for wheelchairs.

Recently, devices for monitoring a patient's condition in real time using a combination of sensor technology and wireless communication technology have been developed. In most human body condition monitoring devices, a sensor for monitoring a patient's condition has been applied to a method in which a sensor is embedded in a band and the band is worn on the patient, or the sensor is directly contacted or inserted into a part of the human body.

The method of embedding the sensor in the band has a problem that the patient has to wear the band and gives the patient an uncomfortable feeling when the sensor is directly contacted or inserted into the human body.

In addition, the existing human body state monitoring device is designed to a fixed space or location environment even if the wireless communication technology is adopted, so that the patient wearing the sensor is not suitable for the mobile environment, such as a decrease in signal reception sensitivity when the patient is moving.

Accordingly, an object of the present invention is to provide a wireless bio-signal monitoring apparatus for a mobile body to monitor the heart rate and respiratory rate in real time during the movement of the patient by using a non-contact piezoelectric sensor to solve the problems of the prior art.

In order to achieve the above object, the wireless bio-signal monitoring apparatus for a mobile body according to an embodiment of the present invention is a sensing sheet is built in a non-contact piezoelectric sensor and placed on a sheet of the mobile body; A transmitter for detecting a heartbeat signal and a breathing signal from a cardiograph (BCG) from the sensing sheet and transmitting the heartbeat signal and the breathing signal through a wireless communication channel; A receiver for receiving the heartbeat signal and the breathing signal and transmitting the received heartbeat signal and the breathing signal to a mobile communication terminal through a cable; A server analyzing the heartbeat signal and the breathing signal received from the mobile communication terminal through a mobile communication network; And a computer connected to the server.

The wireless communication channel is an IEEE 802.15.4 RF wireless communication channel.

The transmitter includes a circuit for removing noise mixed in the heartbeat signal and the breathing signal by the movement of the moving object.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

The present invention uses a non-contact piezoelectric sensor to measure the cardiac ballistic (BCG: Ballistocardiogram) of the patient riding on the moving body, from which it detects heart rate and respiration rate in real time during the movement. The movable body is a movable body on which the human body can sit and move manually or electrically, and includes a manual / electric wheelchair. Cardiac ballistics (hereinafter referred to as "BCG") is a method of assessing the cardiac cycle in a non-contact manner without using electrodes. Signals including BCG are heartbeat signal, respiratory signal, human body movement signal. An embodiment of the present invention detects a heartbeat signal and a breathing signal excluding the human body movement signal from BCG in order to measure the respiratory rate and heart rate in a moving wheelchair in real time.

In addition, an embodiment of the present invention is to produce a non-contact piezoelectric sensor in the form of a sheet to wirelessly detect the BCG of a person moving in a moving object, and apply a transmitter and a receiver using IEE 802.15.4 Zigbee wireless RF communication technology. . The experiment of the present invention was carried out by selecting the movable body by the wheelchair. IEE 802.15.4 Zigbee wireless RF communication technology is a short-range wireless communication method. Low power, large area networking, and communication with multiple devices are desirable.

The present invention has developed a device for measuring the respiratory rate and heart rate from BCG, and built-in 3-axis acceleration sensor to remove the noise added to the BCG signal caused by the vibration of the wheelchair during the movement. The signal obtained from the sensor is recorded on an SD card (Security Digital Card) of a PDA (Portable Digital Assistant) with a receiver via an A / D converter.

In the experimental procedure of the present invention, the data recorded on the SD card was analyzed using a data analysis program for a PC, and the results are shown graphically. Finally, it was confirmed that a warning message can be delivered to a remote server via a CDMA network in case of emergency of a wheelchair-mounted person on a PDA or mobile phone. The experiment was conducted on healthy men and women in their 20s who supported the study. The volunteers conducted an experiment comparing the signals output from the skin temperature amplifier (SKT) sensor provided by Biopac with the signals from the device developed by the research team while standing in a wheelchair. This comparative experiment used Biopac's SKT sensor, which can be used as a standard, to evaluate the superiority of the developed device. In addition, after verifying the comparison between the present invention and the SKT sensor, the respiratory rate and heart rate could be measured in wheelchairs moving through several homes.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 1 to 13.

2 and 3 illustrate a wireless bio-signal monitoring apparatus for a moving body according to an embodiment of the present invention.

2 and 3, the wireless bio-signal monitoring apparatus for a mobile body according to an embodiment of the present invention is a sensing sheet 12, a sensing sheet 12 placed on a sheet of the mobile body 10, the mobile body 10 A cable 13 connected, and a transmitter 14 connected to the cable 13.

The sensing sheet 12 includes non-contact piezoelectric sensors 11. The non-contact piezoelectric sensors 11 include a polypropylene film, and the inside of the film is formed in a cell-like structure using a mechanism in which the thickness of the air-void changes when pressure is applied from the outside. Sensor. The physical mechanism of the non-contact piezoelectric sensor is shown in Equation 1 below.

Δq is the calculated charge, k is the sensitivity variable, and ΔF is the externally applied force.

The transmitter 14 is composed of an A / D converter, a microcontroller, an IEEE 802.15.4 RF wireless communication chip, a non-contact piezoelectric sensor, and an acceleration sensor. The transmitter 14 amplifies the signal from the non-contact piezoelectric sensors, then digitizes and detects a heartbeat signal and a breathing signal from the digital signal BCG. After the transmitter 14 removes the noise included in the heartbeat signal and the respiratory signal by the movement of the moving object 10 using the acceleration sensor, the heartbeat signal and the respiratory signal are converted into the IEEE 802.15.4 RF radio protocol type. Convert and send. The transmitter 14 may transmit a heartbeat signal and a breathing signal in two modes according to a built-in program. In the periodic transmission mode, the transmitter 14 transmits a heartbeat signal and a breathing signal at a preset time period. In the emergency transmission mode, the transmitter 14 counts the heartbeat signal and the breathing signal, compares the count value with a preset reference value, and compares the count value with a preset reference value when the heartbeat and / or respiration rate exceeds the reference value. Send a signal.

The wireless bio-signal monitoring apparatus for a mobile body according to an embodiment of the present invention includes a receiver 21 and a mobile communication terminal 31 to which the receiver 21 is connected, forming a wireless communication channel with the transmitter 14 as shown in FIG. 2. Equipped. The mobile communication terminal 31 may be a mobile phone or a PDA carried by a patient.

The receiver 21 is connected to the SD card of the mobile communication terminal 31 as shown in FIG. 3 to store the heartbeat signal and the respiratory signal received from the transmitter 14 in the memory of the SD card, and to process the packet and generate the packet. The data packet is transmitted to the mobile communication terminal 31.

The mobile communication terminal 31 executes the wireless biosignal processing program, receives the data packet input from the receiver 21, stores the data packet in the built-in buffer, and generates a data file by parsing the data packet received through the serial cable. In addition to storing in the memory, the heartbeat and respiration of the patient riding the mobile 10 is displayed in real time on the indicator. In addition, the mobile communication terminal 31 transmits the data including the heartbeat and respiration information through the CDMA network according to the transmission command of the patient riding in the mobile 10 using the built-in CDMA module as shown in FIG. 4.

The wireless bio-signal monitoring apparatus for a moving object according to an embodiment of the present invention includes a remote server 41 connected to a CDMA network and a computer 42 connected to a remote server 41 as shown in FIG.

The remote server 41 analyzes the heartbeat and respiration information data received through the CDMA network and stores the data in the database. In addition, the remote server 41 checks the position information received from the CDMA network and monitors the position of the patient riding in the mobile body 11 in real time. In addition, the remote server 41 receives the instructions of the doctor and professional counselor who analyzed the heart rate and respiratory rate from the computer 42 and transmits the transfer information to the mobile communication terminal 31 as an SMS message through the CDMA network. .

The computer 42 displays the heartbeat and respiration information input from the remote server 41 and the position information of the patient on the monitor. The doctor in charge and a professional counselor monitor the heart rate and the respiratory rate of the patient in the moving object 10 using the computer 42 in real time, and transmit the transmission information of the patient through the computer 42 in an emergency. ) Or the first aid team is placed in the patient's position.

In order to verify the effect on the present invention, the inventors conducted the following experiment.

In order to compare how accurate the signal output from the device developed by the inventors was selected SKT (Skin Temperature Amplifier) sensor provided by Biopac. SKT sensor is a sensor attached between the nose and the upper lip to detect respiration by the temperature change according to inhalation and exhalation. The sampling rate of the Biopac instrument was adjusted to 200 Hz. In order to proceed with the experiment, one subject and two inspectors were required. The experimental method is as follows. Subjects were seated in wheelchairs (mobile bodies) developed with SKT sensors. One of the two inspectors ran the Biopac program with SKT sensors and the other inspector ran the PDA program developed in this study. After 1 minute, each program is stopped and the experiment is finished.

Experimental results measured at the same time in each sensor are shown in Figs.

Experimental results in three different environments

(1) tine driven manual wheelchair

In order to confirm that the breathing rate can be measured in real time even while moving in a wheelchair, the experiment was conducted as follows. There was no sensor or device that could wirelessly measure breathing rate, which allowed him to count his breathing rate for about a minute. Finally, the respiratory rate counted by the subject himself was compared with the respiratory rate measured in the wheelchair.

Assumption 1 of this experiment is that a person in a wheelchair pushes the wheelchair behind him because he cannot control the wheelchair with his own power. Therefore, the subject only checks his breathing rate.

Experimental Process

Experimental Place: Corridor, Research Institute of Medicine, Chungbuk National University

Experiment distance: 48 m

Experiment time: about 1 minute

Average wheelchair speed: 0.8 m / s

8 is a graph showing a respiratory signal obtained from a subject in an experiment applying hypothesis 1 of a tine driven manual wheelchair.

(2) Self-driven manual wheelchair

In Home 2, a subject in a wheelchair can adjust a manual wheelchair by himself, so he / she drives the wheelchair and checks the breathing rate. This experimental procedure is the same as hypothesis 1. 7 is a result obtained by applying hypothesis 2, and a respiratory signal obtained from a subject. 9 is an experimental result screen showing the results of breathing 20 times for 50 seconds according to hypothesis 2.

(3) Electric Wheelchair

In hypothesis 3, the subject checks his breathing rate while adjusting the electric wheelchair by himself in the electric wheelchair. The experimental procedure is the same as hypothesis 1. 8 is a result obtained by applying hypothesis 3, and a respiratory signal obtained from a subject. 10 shows the results of breathing 17 times for 1 minute according to hypothesis 3.

Experimental results of four normal subjects

As can be seen in Table 1 below, as a result of analyzing the signal output from the SKT sensor provided by Biopac and the transmitter of the present invention, breathing from the other subjects (subject1, subject2, subject3) except one subject (subject4) You can see that the signal is nearly identical. This is a result proved the correctness of the program of the transmitter, the receiver and the mobile communication terminal of the present invention. In addition, it can be seen from the assumption that the actual breathing rate and the number of breaths measured were almost identical if the subject pushed the wheelchair when the subject was in a manual wheelchair. Assumption 3 is also the same as the actual breathing rate and the measured breathing rate as a result obtained from a subject in an electric wheelchair. In case of hypothesis 2, the results of the actual breathing and the measured breathing were inconsistent, which was the noise caused by the subject driving the wheelchair directly.

Table 1 shows the results of the respiration comparison of each subject.

Environment biopac / sensing sensor 1.Respiration / Measurement 2.Respiratory breathing / measurement 3.Respiratory Breathing / Measurement biopac Sensing Sensor subject1 20/19 17 / Not measurable 17/16 14 14 subject2 21/20 20/25 21/21 15 15 subject3 16/16 10/19 14/14 16 16 subject4 14/11 22 / Not measurable 25/18 15 12

3-axis acceleration  Sensor data

The BCG signal measured in a wheelchair is a mixture of a human motion signal and a wheelchair motion signal in the form of noise. The noise signal affects the breathing signal and the heartbeat signal of the BCG signal. Therefore, the present invention has developed an algorithm that can remove this signal component by embedding the 3-axis acceleration sensor in the transmitter. FIG. 11 shows signals generated when adjusting the wheelchair, and FIG. 12 shows signals obtained from the three-axis acceleration sensor. FIG. 13 shows a result of calibrating a BCG signal using a three-axis acceleration sensor.

As described above, the wireless bio-signal monitoring apparatus for a mobile body using a non-contact piezoelectric sensor according to an embodiment of the present invention using a non-contact piezoelectric sensor, a transmitter, a receiver, and a mobile communication terminal in real time during the movement of the patient, heart rate and respiration rate. Can be monitored accurately.

As confirmed in the experimental results, it was confirmed that excellent results were obtained from the data of all the subjects except one subject. Also, in Home 2, many subjects were unable to measure respiratory rate due to body movement and wheelchair vibration caused by manual wheelchair adjustment.

The present invention uses a three-axis acceleration sensor to remove the motion signal affecting the BCG signal.

The present invention can transmit data to a remote server when an emergency occurs by using the CDMA module of the mobile communication terminal connected to the receiver.

In addition, the present invention can non-invasively detect the biological signal of the subject in real time even during the movement of the moving object. Herein, non-invasive means a method of not directly contacting a sensor to a human body of a patient.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (3)

A sensing sheet having a non-contact piezoelectric sensor embedded therein and placed on a sheet of the moving body; A transmitter for detecting a heartbeat signal and a breathing signal from a cardiograph (BCG) from the sensing sheet and transmitting the heartbeat signal and the breathing signal through a wireless communication channel; A receiver for receiving the heartbeat signal and the breathing signal and transmitting the received heartbeat signal and the breathing signal to a mobile communication terminal through a cable; A server analyzing the heartbeat signal and the breathing signal received from the mobile communication terminal through a mobile communication network; And Wireless biological signal monitoring apparatus for a moving object using a non-contact piezoelectric sensor characterized in that it comprises a computer connected to the server. The method of claim 1, The wireless communication channel is a wireless bio-signal monitoring apparatus for a mobile object using a non-contact piezoelectric sensor, characterized in that the IEEE 802.15.4 RF wireless communication. The method of claim 2, The transmitter is a wireless bio-signal monitoring apparatus for a mobile body using a non-contact piezoelectric sensor characterized in that it comprises a circuit for removing the noise mixed in the heartbeat signal and the breathing signal by the movement of the mobile body.

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