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See discussions, stats, and author profiles for this publication at: evelopment of portable biofeedback devicesfor sport applicationsCONFERENCE PAPER · APRIL 2015READS352 AUTHORS:Tan CHOON MongZulkifli AhmadUniversiti Malaysia PahangUniversiti Malaysia Pahang2 PUBLICATIONS 0 CITATIONS16 PUBLICATIONS 5 CITATIONSSEE PROFILEAll in-text references underlined in blue are linked to publications on ResearchGate,letting you access and read them immediately.SEE PROFILEAvailable from: Zulkifli AhmadRetrieved on: 09 November 2015

Development of portable biofeedback devicesfor sport applicationsTan Choon Mong, and Zulkifli Ahmad*Human Engineering Group,Faculty of Mechanical Engineering, Universiti Malaysia Pahang26600, Pekan, Pahang, MalaysiaCorrespondent Author: kifli@ump.edu.myAbstract—The purpose of this project is to propose a portablelow cost of ECG and EMG devices that plays the role ofcontinuous monitoring of the user heart rate and muscle eElectrocardiography (ECG) and Electromyography (EMG) areimportant in the field of healthcare and sports which enable toassess the physiological state and training progress of athlete.Heart rate can reflect individual natural fitness whereas theEMG signal indicates muscle activation and fatigue level thusdetermine the performance. However, most of the EMG andheart rate measuring tools are expensive and large in size. Theprocess of data collection also often confined to hospital orbiomechanics lab. Therefore, the development of this monitoringsystem capable provides immediate feedback about physiologicaldata which is desired by athletes and trainers. The monitoringsystem is knitted with a pulse sensor and muscle sensor V3.Arduino Uno was act as microcontroller to analyze the collectedsignal then transmits the data via Bluetooth to Android basedsmartphone; Laptop through Processing software; or LCDscreen. The significant of using Processing software is allowdisplay the data in graphical way. The pulse sensor is applyingphotoplethsmography (PPG) technique to measure the heart ratein beats per minute (bpm). In other hand, the EMG signal will becollected by passive electrode which allows the monitoring of usermuscle stress. Throughout the ECG experiment, the pulse sensorresult collected via Coolterm application was compared to radialpulse and Treadmill. The result showed that the error rate of thedevice is negligible and promising. While the EMG dataproduced by muscle sensor is achieving a full wave rectifiedwaveform that demonstrates the forearm strength romyography(EMG); Microcontroller; athlete.I.INTRODUCTIONBasically, Electrocardiography (ECG) and SurfaceElectromyography (EMG) are non-invasive technique andmonitoring tools for the detection and measurement ofheartbeat and EMG signal. Biosignals of ECG and EMG notonly play an important role in patient health monitoring butalso assess the physiological state of athlete in trainingprogress.ECG is used to evaluate the cardiac abnormalities anddetect how fast your heart is beating [1] whereas EMG is usedto analyze the muscle activity by recording the electricalactivity produced by skeletal muscle during muscle contractionand relaxation cycle [2]. In modern live, both techniques haveincreasing important in sports for biomechanical analysis. Thedata heart rate capable provide good indicators of exerciseintensity and fitness respectively by inform athlete about hishealthy and effective exercise behavior [3].Surface EMG canhelp to understand the muscle activation in specific movementwhich may lead to healthy training by improve the utilizationof muscle and prevent risk of injury [2].The conventional ECG and EMG tools were expensive andbulky. Therefore, the experiment was confined in hospital orbiomechanical lab. Beside this, both measurement methodswere using conductive electrodes which directly attached to theskin with help of gel. These kind of method was not reusableand troublesome where not optimal for long term used as aresult of surface degradation of the electrode and require thecleaning of target muscle [4].Such situation has lead to certain needs for lower cost , userfriendly and portable heart rate and muscle activity detector inorder to achieve the purpose of continuously monitoring theathlete physiological information [5]. In the sport domain, thereis a trend to personal monitoring. Thus, there is a growing needfor solution to record and analyze the biosignal on mobiledevices. Hence, with the help of Bluetooth module, the datacollected were capable transmit to Android base smartphonefor further analyzing.II.DEVICE DEVELOPMENTFig. 1 shows an overview of the device system monitoring.This project is proposed to develop a system by using ArduinoUno as microcontroller to perform analog to digital (A/D)process. It compatible for both pulse and muscle sensors todetect and measure the heartbeat and muscle activityrespectively.A. Electrocardiography (ECG)For ECG system application, the pulse sensor was chosenwhich applied the photoplethysmography (PPG) technology tomeasure the heartbeat. Basically , PPG tools is an inexpensiveand less power consume optical technique which measure theblood volume change in the vascular tissue [6]. The PPG ispreferred in the portable design due to small size and withoutprecise positioning the sensor on subject body compared withconventional ECG. Pulse sensor is reflectance mode where the

photo-detector sensor and LED placing on the same side oftissue. The pulse sensor work by green light shining into veinsand a light source measure the reflected light and convert intoan analog voltage. The pulse sensor can attach on finger orearlobe.both the digital value of pulse sensor and muscle sensor data asshown in Fig. 2. Next, Processing is an open sourceprogramming language which serves as visual context by graphthe data from the microcontroller as shown in Fig. 3. Lastly,Bluetooth module is attached which act as bridge between themicrocontroller and Android based smartphone. The data frommicrocontroller will transmit to phone wirelessly by Bluetoothmodule and display through Blueterm as shown in Fig. 4.Fig. 2. LCD screen display heart rate and EMG.Fig. 1. An overview of the device system.B. Electromyography (EMG)In contrast, muscle sensor was applied as EMG system. Themuscle sensor include surface electrode which attach on targetmuscle will collect the raw EMG signal to muscle sensorcircuit. The electrode measures the voltage difference whichgenerate by muscle activation. The muscle sensor thenamplifies, filtered and rectified the raw signal from humanmuscle and send to Arduino Uno. In the application of musclesensor, the strength of muscle contraction is correspond to theamount of voltage output which mean the voltage output isdepending on the amount of activation in the targeted muscle.There are three platforms to display the collected data.Firstly, it can be display in Personal Computer (PC) viaProcessing programming interface. Second, with help ofBluetooth module, the data can send to Android based smartphone wirelessly via Blueterm apps. Lastly, the data also candisplay in LCD directly after connect with the Arduino Uno.The systems have considerable portability due to lowweight and small size of component. Furthermore, the ArduinoUno is chosen as microcontroller due to it is a compact sizedevice that has capability of high speed analog to digitalconversion as well as low cost. For wireless technology ofcommunication, the Bluetooth module was use in transmissionof heartbeat and muscle activity data due to its low cost andsmall size. Meanwhile the Processing software was used todisplaying the data from Arduino serial monitor in graphicalway. There are about five main components in the developmentof system. The most expensive part is muscle sensor of thecurrent device. However, this device is still low cost comparedto the traditional ECG and EMG device from clinic or hospitalwhose are too expensive and cannot to be as portable.III.EXPERIMENTAL DATAAfter set up the connection of pulse sensor and musclesensor to Arduino Uno, it then needs to create a platform todisplay the collected signal. The data which display by LCDscreen is same with serial monitor of Arduino board. It displaysFig. 3. Displaying heart rate (left) and muscle activation (right) viaProcessing programming interface.Fig. 4. Displaying ECG data on Android phone via Blueterm App.A. ECG validation processThe pulse sensor can either attach in finger or earlobe toperform the measurement. Moreover, the pulse sensor does notrequire skin preparation as it is placed directly in contact withthe skin. According to [6] stated that PPG are often attach toear or fingertip which are single site measurement where thepulse can easily be detected. Therefore, in order to maximizethe utilization of pulse sensor, the comparison between thefingertip and earlobe were conducted to identify which sites ofmeasurement are more reliable. As shown in Fig. 5, the pulsesensor was sewing on the index finger position of glove inorder to ease the user to wear the pulse sensor instead of strap itwith finger. Next, a sticker is stick on the surface of pulsesensor which is to prevent the sweaty or oil fingers which mayaffect the signal collection. In other hand, the secondexperiment is hot glue the pulse sensor on the ear clip forfurther measurement.