Implementation of patient monitoring system using gsm technology 2

International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
INTERNATIONAL JOURNAL OF ELECTRONICS AND
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 1, January- February (2013), © IAEME
COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)
ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Volume 4, Issue 1, January- February (2013), pp. 18-24
IJECET
© IAEME: www.iaeme.com/ijecet.asp
Journal Impact Factor (2012): 3.5930 (Calculated by GISI)
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IMPLEMENTATION OF PATIENT MONITORING SYSTEM USING
GSM TECHNOLOGY
Manish M. Patil 1 Prof. Chhaya S. Khandelwal2
ME (E.C.) JNEC Aurangbad1 Assistant Prof. JNEC Aurangabad2
manish_107.77@rediffmail.com chaya.khandelwal@rediffmail.com

ABSTRACT

In this fast pace of life it is difficult for people to be constantly available for their near ones
who might need them while they are suffering from any disease or physical disorder. So also constant
monitoring of the patients body parameters such as temperature, pulse rate, sugar level etc. becomes
difficult. Also in intensive care units it is necessary to monitor continuously the patient’s health
parameters and keep their record. But there is a possibility of human errors. Hence to remove human
errors and to lessen excessive burden of continuously monitoring patient’s health from doctor’s head,
we are proposing patient monitoring system using GSM. A patient monitoring system which provides
continuous monitoring of a patient includes a data acquisition & processing module which receives
physiological data from the patient and GSM module to transmit acquired data to doctor’s mobile.
This unit may be inserted in a bedside display unit to display the physiological condition of the
patient. Patient monitoring systems measure physiological characteristics either continuously or at
regular intervals over time.

INTRODUCTION

In this fast pace of life it is difficult for people to be constantly available for their near ones
who might need them while they are suffering from any disease or physical disorder. So also constant
monitoring of the patients body parameters such as temperature, pulse rate, sugar level etc. becomes
difficult [4]. Also in intensive care units it is necessary to monitor continuously the patient’s health
parameters and keep their record. But there is a possibility of human errors[6]. Hence to remove
human errors and to lessen excessive burden of continuously monitoring patient’s health from
doctor’s head, we are proposing patient monitoring system using GSM.
The concept of this paper is builds upon the integration of wireless communications into
medical applications to revolutionize personal healthcare. The objective of this project is to build a
wireless heart beat monitoring system using GSM Technology, which could potentially be an integral
part of a suite of personal healthcare appliances for a large-scale remote patient monitoring system.
As its name implies this is a Patient monitoring system, with a feature of sending SMS to
doctor and patients relative in event of emergency, hence the system can be used at hospitals as well
as at home. Remote patient monitoring will not only redefine hospital care but also work, home, and
recreational activities [4].

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The objective of patient monitoring system is to have quantitative assessment of important
physiological variables of patients during critical conditions[1-6]. This system is used for measuring
continuously automatically the values of the patient's important physiological parameters such as
blood pressure, body temperature, pulse rate, respiration rate and other health-related criteria.
The proposed system is portable and can be used at home. In the proposed system
microcontroller is used so the cost of the system will very less. For transmission of message GSM
technique of messaging can be used, due to that message can be sent any time any were in the
network. So the proposed system is very cost effective and the vital parameters are measured and sent
accurately to the numbers which are already store in the system. So the efficiency of hospitals and
doctors can be increased by the proposed system. The programming is in assembly language and AT
commands of GSM is used for the transmission of message.

SYSTEM DEVELOPMENT

Figure 1.1 shows the block diagram of the Patient Monitoring System. Various physiological
signals such as body temperature, blood pressure, heart rate are continuously monitored as well as
controlled remotely with this system.
Various types of transducers are used to sense these bioelectrical signals [1,2]. To sense the
body temperature we used LM35 of national instruments because it is cheap in rate and its size is
small enough to fit on patient’s body [11]. Heart rate sensor is non invasive type of sensor based on
photo plethesmography principle [1,2]. The heart rate sensor is designed by us only to reduce the
overall cost of proposed system. This circuit consists of instrumentation amplifier and ECG electrodes
which are not costly. The ECG signal is collected with the help of three electrodes. Out of which one
is a reference electrode, one is connected to the left side and other to the right [2]. This collected
signal is given to instrumentation amplifier and the remaining circuit, which counts the number of R
peaks per minute and gives the accurate Heart rate.

Figure 1.1: conceptual block diagram of the system

All the signals from transducers are weak signals hence these signals are processed and
amplified to desired level with the help of signal conditioner and instrumentation amplifier. The
output of instrumentation amplifier is given to analog to digital converter. These converted digital

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signals are then fed to microcontroller 89S52. Microcontroller displays these respective values on
LCD display. Microcontroller then compares these values with the hard coded values given
to microcontroller by user through keypad. These values are stored in memory of
microcontroller. If measured values cross the limit of reference values then microcontroller
will activate relay which is connected to alarm circuit. It also send SMS to two mobile
numbers stored in memory through GSM modem. Microcontroller continuously displays
these variables on the LCD Display. Microcontroller continuously does this work, thus
providing a real time monitoring of temperature heart rate and blood pressure.
HEART RATE SENSOR DESIGN
As the sensors which are used in medical field are very costly, to reduce the cost of
developed system heart beat measurement sensor is developed using different OAMPS such
as LM 358,OPAMP 07 and other IC’s as MCT2E, IC 4538 etc[10]. This sensor is based on
the concept of ECG[2]. In the developed system three electrodes are used as ECG leads. Two
of them were connected on the body and the third one was used as ground. The circuit
diagram of developed heart rate measurement sensor is as shown in figure 1.2

Figure 1.2:- circuit diagram of heart rate sensor
In the developed system chest sensors are used for sensing ECG signal. Three
electrodes are used for sensing signal out of which one electrode is used as a ground and
remaining two are connected to body one at left side of chest and other at right side of chest.
Range of this ECG signal is in Mv[2] but the input required for ADC is near about 2.5 volts
hence the gain of overall system is set to 1000

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Output of the ECG sensors is then given to instrumentation amplifier. All the resisters
connected to instrumentation amplifier are of 20 k and gain adjust register is of 1 k , hence
the gain of instrumentation amplifier is calculated as, IC 620 is used as instrumentation
amplifier in the developed system [9].
ܴଶ
‫ܩ‬ଵ ൌ 1 ൅
ܴଵ
2 ‫଼01 כ 01 כ‬
ൌ 1൅ ൌ 21
1 ‫଼01 כ‬
Output of instrumentation amplifier is given to the opt coupler MCT2 and then it is given to
next processing circuit. ECG signal used for diagnostic purpose is in the range of 0.05 Hz to
100 Hz, but the required signal for the system is from 0.5 to 30 Hz, hence design a high pass
filter having cut off frequency 0.5 Hz
1
‫ ܨ‬ൌ
௖
2ߨܴ‫ܥ‬
Take R=330K
1
0.5 ൌ
2ߨ ‫01 כ 033 כ‬ଷ ‫ܥ כ‬
‫ ܥ‬ൌ 9.64 ‫଻ି01 כ‬
Output of this high pass filter is now given to single amplifier whose gain is set to 1000/ 21=
47.61. the gain of this amplifier is adjust to 47.61 so that overall gain of the system is 1000.
Gain of this amplifier is given by
ܴ௙
‫ܩ‬ଶ ൌ 1 ൅
ܴଵ
Select value of Rf = 100 K .
ଵ଴଴௞
47.61 ൌ 1 ൅ ோ
భ
R1= 2.14K
2.14 k is not standard register value, so fix register of 1.8 k is chosen and pot of 1 k is
used to adjust the value of 2.14 k
The notch filter is used to eliminate the 50 Hz frequency signal. It is narrow band reject filter.
Notch out frequency is the frequency at which maximum attenuation occurs.
݂௡ୀ ଵ
ଶగோ஼
In notch filter design C ≤ 1µF hence C =0.068 µF
‫ ܴ ׵‬ൌ 46.81‫ܭ‬
Hence taking standard value R=47 ‫ܭ‬
The output of notch filter is given to the DC offset null circuit. The DC offset present in the
system may vary from 0.2 to 25 mV. This circuit is used to remove this offset present in the
system. From data sheets maximum input DC offset for P07 is 25 µV. The gain of system is
1000 hence the maximum DC offset is 25 mV.
The maximum possible output offset voltage Voo caused by the input offset voltage Vio is.
ܸ‫ ݋݋‬ൌ ܸ݅‫݋݋ܣ כ ݋‬
ࡾࢌ
࢝ࢎࢋ࢘ࢋ ࡭࢕࢕ ൌ ૚ ൅ ࡾࢇ
ାࡾ૛૜
૝
Where Rf = 3.9 K , R23 = 8.2 K Ra =100K
‫ ݋݋ܣ ׵‬ൌ 1.117
Therefore maximum DC offset that can be removed by this circuit is
ܸ‫ ݋݋‬ൌ 27.952ܸ݉

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After removing Dc offset the signal is given to comparator LM324. It compares this
signal with the reference signal and gives compared output. For comparator reference voltage
is obtained from voltage divider arrangement of 10 K register and 10 K pot at the
inverting terminal and input signal is given at non inverting terminal. The signal from
comparator is given to the multi vibrator 4538 which gives square pulses according to
compared signal these pulses later on given to microcontroller.

WORKING PRINCIPLE

In the developed system LM35 is used as temperature sensor. It gives analog output,
which changes 10mV per degree Celsius. This sensor output is given to the ADC 808. The
ADC808 gives digital count corresponding to the input voltage applied to it. Input Voltage in
the range of 0V to 2.5V is given for each sensor. The corresponding digital output will be 0 to
255. In the developed system potentiometer is connected in voltage divider circuit for the
simulation of blood pressure sensor. The output of the voltage divider circuit is connected to
the ADC808 which converts it to the digital count. In the developed system chest sensors are
used and circuit is designed for sensing heart signal.
The outputs of these sensors are given to ADC808. The channel select pins A B C of
ADC808 are connected to the port pins-P3.2 of micro controller. We can select different
channels by changing the status of these pins. The ADC808 is 8 channel ADC having 8-bit
resolution. The conversion time of ADC808 is 100 microseconds and its step size is 20 mV.
The data lines D0 to D7 of the ADC are connected to the port1 micro controller. When ADC
receives pulse on SOC pin (PORT P3.4) from micro controller it starts the analog to digital
conversion. After completion of conversion it gives pulse on EOC pin (PORT P3.3).
The output of the ADC is in hex format. The micro controller will convert it into BCD
format and then into ASCII format to display different readings of different parameters on
LCD. The data lines D0-D7 of LCD are connected to port 0 of micro controller. The control
lines RS (Register select), R/W (read/write) and Enable of LCD are connected to port pins
P3.5, P3.6, P3.7 of micro controller respectively.
Whenever temperature, heart rate or any parameter exceeds there selecting range at
that time message will be sent through GSM port which is connected though MAX 232.
ECG sensor Card

GSM modem

Master card

Figure 1.3: Photograph of implemented system

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RESULT

The different physiological variables to be monitored & controlled remotely are
sensed & converted into analogous form i.e. the digital form. Here microcontroller performs
various operations & gives desired output. We have partially implemented the project to
monitor temperature heart rate and blood pressure of the patient remotely.
For testing system following steps will perform:
1. By using keypad enter mobile no. to witch message is to be sent
2. Enter second mobile no. to witch message is to be sent
3. Set time after witch message is to be sent
4. Set temperature limits using keypad
5. Set heart rate limits using keypad
6. Set blood pressure limits using keypad
Testing results are as shown in table 1.1 through 1.

Table 1.1 test results for normal conditions

Table 1.2 test results when temperature exceeds limits

CONCLUSION

After successful completions of this project it can conclude that the microcontroller
based system can be effectively used as communication medium in conjunction with GSM.
Sensors designed in the developed system gives accurate readings so it can be said that the
developed system is very cost effective and accurate. The accuracy of the system is up to
99%.

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REFERENCES

[1]. Biomedical Instrumentation and measurements - Cromwell and Weibell
[2]. Introduction to biomedical Equipment Technology - Carr Brown
[3].C.Andersson GPRS & 3G wireless Applications,Wilay 2001
[4].Maglaveras, N., Home care delivery through the mobile telecommunications platform
PMID:12467795 [PubMed - indexed for MEDLINE]
[5]Schwartz, G.R. (1999) Principles and Practice of Emergency Medicine. King of Prussia,
PA: Rittenhouse Book Distributors.
[6]. Park Set al, Real-time monitoring of patient on remote sites. Proceedings of the 20th
annual international conference on IEEE EMBS, vol. 20, No.3; 1998.
[7]. Myung-kyung Suh & Chien-An Chen & Jonathan Woodbridge “A Remote Patient
Monitoring System for Congestive Heart Failure”
[8]Alexander G. Logan, Warren J. McIsaac, Andras Tisler, M. Jane Irvine ”Mobile Phone–
Based Remote Patient Monitoring System for Management of Hypertension in Diabetic
Patients”
[9]. Coughling,Driscoll - Op amps and Linear Integrated Circuits, Pearson education, 6/e
[10]. Ramakant Gaikward - Op amp and Integrated circuit, PHI
[11]. National Semiconductor Corporation, LM35 datasheet, precision centigrade
Temperature sensors, Atmel data book
[12] B.Sambath Kumar and Dr.S.S.Rau, “A Study on Service Oriented Architecture in
Electronic Patient Health Record System” International Journal of Management (IJM),
Volume3, Issue1, 2012, pp. 165 - 168, Published by IAEME
[13] Vani. Surapaneni and V. Shanthi Sri, “Monitoring and Fall Detection of Patients using
Mobile 3-Axis Accelerometers Sensors” International journal of Electronics and
Communication Engineering &Technology (IJECET), Volume3, Issue2, 2012, pp. 41 - 47,
Published by IAEME

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Implementation of patient monitoring system using gsm technology 2

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