Design of Heartbeat Detector Based on Pressure Sensor
Dept. of Electrical Engineering Gunadarma University
causing hearbeats too fast, too slow or irregularly [2]. Arrhythmias can take place in a healthy heart and be of minimal consequence but they may also indicate a serious problem that may lead to stroke or sudden cardiac death [3]. Heart arrhythmia treatment can often control or eliminate irregular heartbeats.
Wahyu Kusuma R.
Dept. of Electrical Engineering Gunadarma University
Jakarta, Indonesia wahyukr@staff.gunadarma.ac.id
Jalinas
Dept. of Computer System Gunadarma University
Jakarta, Indonesia jalinas@staff.gunadarma.ac.id
Elvyra N.
www.irjetm.com
Design of Heartbeat Detector
Based on Pressure SensorJakarta, Indonesia elvyranasution@student.gunadarma.ac.id
Abstract —Heartbeat Detector serve as an instrument used to calculate the heartbeat humans with sphygmomanometer, using arduino as processors, as well as censorship mpx5050dp detection as heart rate and blood pressure. Sensors will take the data of the parameters of which is measured. From the data which the parameter measured it will be showing how much the number of human heart rate. The method in this research is to process the input signal from the pressure sensor mpx5050dp, the signal amplified by the signal conditioner, Arduino detect inter-pulse period. The hardware used consists of a sphygmomanometer and pressure sensor mpx5050dp as heart rate detection, and signal conditioning board Arduino Uno as a processing of data. Design software in the system uses the Arduino IDE language C based programming. The result is different to each person because of his or her condition and age. Based on measuring the ten respondents, comparison result between heartbeat sensor and pulse oxymeter have error rate 6.47%. The error rate is so high because the measurement takes for 10 seconds. Pulse oxymeter takes 10 seconds to calculate the heart rate, so the authors also takes 10 seconds as well to experiment.
Electrocardiogram (ECG) is a diagnosis tool that reported the electrical activity of heart recorded by skin electrode. The morphology and heart rate meditates the cardiac health of human heart beat [4]. It is a noninvasive technique [5]. The ECG signal provides important information of a human heart for detection of diseases. To acquire the signal, ECG devices with varying number of electrodes (3
- –12) can be used. Multi lead systems exceeding 12 and up to 120 electrodes are also available [6].
I. INTRODUCTION The heart is an organ of human body which has a vital function, small abnormalities can have a big impact on the performance of the heart. Illness of the heart is the number one cause of death in the world. Based on data from the World Health Organization (WHO), cardiovascular disease has reached 29% in the percentage of deaths in the world and 17 million people die every year due to heart and blood vessel disease throughout the world [1].
Index Terms — Sphygmomanometer, heartbeat, pressure sensor, Arduino Uno, LCD display
Technology has been widely used on various aspects, one of which is in the medical world. A lot of medical equipment that used to work manually now working digitally, for example is Sphygmomanometer. Sphygmomanometer is a device used to measure human blood pressure. Sphygmomanometer is often used today is the analogue sphygmomanometer that use mercury in a scale tube as an indicator of measurement results [7].
This analogue sphygmomanometer only used by medical, and it is difficult to do by a layman, so to do blood pressure checks society should go to a doctor or clinic. For that it needs to be made digital sphygmomanometer that can help people in measuring blood pressure practically, easy to read, and more efficient. So when use it does not need to be done by the medical even by a layman is readable. In this digital sphygmomanometer, use MPX5050DP pressure sensors [8] are useful for measuring blood pressure. The sensor size is relatively small so easy to put on the circuit. The voltage on the sensor can also be determined based on the needs of the circuit. The sensor is also equipped with a channel that is used to connect the hose in the cuff
Heart arrhythmias occurs when the electrical impulses in heart that coordinate your heartbeats don’t work properly
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with the condition of the pressure to be measured. Also used a microcontroller Arduino Uno [9] which serves as a controller throughout the circuit. The signal received by the microcontroller will be processed as input in the program to count the number of heartbeats per minute. If the microcontroller receives a high signal from the heart rate then the counter will be increased by one [12]. The output of the microcontroller is the number of heartbeats per minute is displayed on the LCD screen.
II. MATERIALS AND METHODS In general, the system will be built at the end of this project can be seen in the block diagram below: Sensor (MPX5050DP) read the blood pressure pulse Conditional signal filter the signal from sensor Arduino Uno process signal to known the heart beat People put the cuff on their arm and then Press To Sphygmomanometer Display BPM of heartbeat on LCD
Fig. 1. Diagram block of heartbeat detector system
The sensor system will detect input signal when people put their arm on the cuff that is connected with the sensor. Sensor MPX5050DP detects a heartbeat based on the pressure of blood in the human arm, as a sign on input board there was a LED will blinking when signal detected, light of LED output was a sign of heartbeat.
Voltage value out of the signal conditioning circuit is processed by the microcontroller Arduino. Outcome of these devices is showing heart beats of human on the LCD display.
A.
System Design Fig. 2. Devices of heartbeat detector based on Arduino Uno
In figure 2, shown hardware design of the device is divided into five parts i.e sphygmomanometer, sensor, conditional signal, microcontroller and LCD display. Sphygmomanometer or blood pressure meter is a device used to measure blood pressure. Sensor system on the device using pressure sensor MPX5050DP. Signal conditional using LM358 to amplified the signal, where as for microcontroller using ATmega328 which is the base of the board Arduino Uno, output of system displayed on LCD display 16x2. The schematic of hardware design of can be seen in Figure 3.
Fig. 3. Schematic of heartbeat detector system
When the tool is run, then the tool will calculate the heart rate.Filling the air in the sphygmomanometer cuff is done so that the MPX5050DP sensor can detect the heartbeat and obtained the result of the initial pressure value are in the range of the human heartbeat.
Because output value of the sensor is to low around 100mV, need signal conditional that will erase high frequency noise and amplify signal to around 0V-5V.
Microcontroller will receive input values from signal conditional. The results of the reading sensor system is processed by the microcontroller.Output will be displayed on LCD display 16x2. www.irjetm.com B.
StartTime was used on program to give flag on clock of
Software Design
the system to sign of start point. Command millis() was used Software design describes the design and description of to command on the system to start the computation time in a how the device works in the form of programs. The design matter of mili-second count. Command elapsedTime was of the system using the Arduino programming used to store value of interval between to peak heartbeat softwareknown as
IDE (Integrated Development signal. Command blinking was used to start counting the Environment). Programming with Arduino IDE is easier, computation time of millis(). because the programming is much simpler and has libraries
Flowchart on figure 4 will explaining detail of the that can help in building the system. The Arduino IDE is system. Program will initialize the port, declare variables used in this system is version 1.0.5. Some processes are used and configure the pins of the LCD. After that the program in the design of this system include: will check the pressure in the cuff, if the MPX5050DP
startTime pressure sensor has been activated sensors will begin to elapsedTime detect and the program will start counting. But if the sensor millis() does not detect any pressure on the cuff, the program will re-
blinking check the pressure. When the program starts counting, there will be a delay for 10 seconds. After that will be reading the sensor value, then the results will be displayed on the LCD REGISTER VARIABLE INITIALIZATION START screen.Below is a flowchart of the program to be made. LCD DISPLAYS:
III. DEVICE TESTING AND ANALYSIS This device uses a three-step process to obtain the required
“SELAMAT DATANG”
value signal in the data processing. The first analysis used PIN2 = LOW No the sensor output signal from the MPX5050DP, will be (BUTTON PRESSED) pass filter first, the third and final analysis of the output Yes analyzed both the output signal of the op-amp and a low signal of the op-amp and a second low pass filter. DETIK = 1 The first analysis used the sensor output signal from the pressure sensor MPX5050DP. LCD DISPLAYS: DETIK + 1 Following figures shows output signal when sensor does not detect heartbeat and when sensor detects heartbeat.
“Menghitung…” DELAY = 100ms A1 A1 = HIGH COUNTER+1 ≠ A1' Yes DISPLAY BPM ON LCD No CONDITION) DETIK = 100 No A1' = A1 (A1 LAST COUNTER*6 BPM = Yes Fig. 4. Flowchart Program of heartbeat detector system Fig. 5. Output signal when sensor does not and detect heartbeat www.irjetm.com
When the sensor does not detect a heartbeat there is a signal with a very small voltage (between -26mV to 24mV)
Overall System Testing
which is the noise of the sensor. When the sensors detect the Device testing system is performed on both of the heartbeat signal has a higher voltage (-32mV to 142mV) respondent's arm, right arm and left arm. which indicates the presence of a heartbeat. Signals from the sensors are still very weak that need to be strengthened to make it easier to measure.
Fig. 7. Testing heartbeat detector device for respondent TABLE I. TESTING RESULT OF HEARTBEAT DETECTOR FOR TEN RESPONDENTS
Fig. 6. Output signal processed by conditional signal stage 1 and stage 2
Figure 6 shown output signal of sensor then processed by conditional signal. The signal filtered and amplified using two stage active low pass filter. The cut-off frequency of the each filter can be calculated using following equation:
(1) This frequency will be set as reference whether the input frequency will be passed or stopped. If the input signal has
Table I shows measurement result to ten respondents. frequency above cut-off frequency the signal will be
The result is different to each person because of his or her attenuated and vice versa. Based on figure 6, gain of first condition and age. Based on tab le’s data, comparison result stage of low pass filter can be determined by following between heartbeat sensor and pulse oxymeter have error equation: rate 6.47%. The error rate is so high because the measurement takes for 10 seconds. Pulse oxymeter takes 10 seconds to calculate the heart rate, so the authors also takes
And for the second stage: 10 seconds as well to experiment. www.irjetm.com
IV. CONCLUSION Based on the testing of hardware and application programs also the analysis has been done in the making of this final task can be concluded that this research has been successfully to detect, calculate and determine heartbeat. The system is designed to use Arduino Uno Board, pressure sensor MPX5050DP and LCD display. Based the tests that has been done to ten correspondent, the device has error rate 6.47% compared with pulse oxymeter.
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