EZ430-Chronos Watch as a Wireless Health Monitoring Device

EZ430-Chronos Watch as a Wireless Health Monitoring Device I.N.A. Mohd Nordin, P.S. Chee, M. Mohd Addi, and F.K. Che Harun Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor

Abstract— The paper describes a wireless health monitoring system, developed in LabVIEW, which is able to transmit and receive a patient’s body signal wirelessly to an eZ430Chronossport watch.Patient’s vital body signal such as heart rate andpercentage of oxygen saturation will be wirelessly transmitted to a programmable eZ430-Chronos watchto easepatient monitoring. The watch, used as a monitoring device will be worn by the doctor or any other individuals who is responsible in monitoring a patient’s condition (i.e.nurse or any of the patient’s family members). The system enables the user to be alerted immediatelyshould any abnormalities occur to a monitored patient and he/she can be attendedinstantly. This would improve patient monitoring system remotely within the wireless protocol given.

Ming, et al. [4]proposed a portable ECG measurement device based on MSP430 MCU, which is small, light, low powered and used to analyze arrhythmia. The device uses a16-bit MCU-MSP430 with the integration of amplifier circuits, filter circuit, wireless transmitting-receiving circuit, data management, keyboard and LCD display. In this design, thetypes of electrodes used are the ones that stick ontothe patient’s chest, making the device suitable for long monitoring. Even aggressive movementsduring surgery would not give much errors to the measurement [4].

Keywords— wireless monitoring device, heart rate, oxygen saturation, eZ430-Chronos.

I. INTRODUCTION Fig. 1 Texas Instrument eZ430-Chronos programmable sport watch [5] Research in the field of telemedicine has developed and expanded vastly over the years, where at present, wireless monitoring devicesarewidely used in enhancing the provision of emergency medical care. Such applications provide increased flexibility and portability for physiological parameter measurements in areas where cables are not feasible. In 1999, Pettis et al., [1]evaluated the efficiency of handheld computer screens used by cardiologist. Electrocardiogram (ECG) signals from 12-leads attached to the patient were transmitted from remote locations to the cardiologists. They believed that if the interpretation of ECG data from the newly designed computer-based system were reliable, the treatment time for cardiac patients will be shortened. Diagnosis by cardiologist was proven to be significantly similar when viewing LCD-displayed ECG and paperdisplayed ECG[1]. Due to patient’s physical restrictions when connected to cables and machines, Taylor,et al.,[2]had designed wireless transducers for cardiotocography via radio frequency (RF) telemetry, where there was no wire connection between the transmitter and the receiver. Thus, patients feel more confortable and at ease to move. There are also many other existing researches regarding wireless transmission of ECG signals, and the transmission is always to a laptop or a personal computer (PC)[3-4].

Figure 1 shows an eZ430-Chronos sport watch, a product of Texas Instrument which has been widely used in various wireless applications.Zhou Z. [6] has developed the watch to be used as an electronic door locking device [6]. The watch was programmed to communicate wirelessly with the device attached to the door for the door to be locked and unlocked. This is done by tapping on the watch’s 3-axisaccelerometer which is located on the watch’s liquid crystal display (LCD). Thisproves that the wireless communication of the watch can be developed as long as the RF transceiver used is suitable for low power wireless applications. The objective of this project is toexpand the application of telemedicine with a slightly different approach by utilizing the current wireless wearable device, eZ430-Chronos watch (from Texas Instrument) as a wireless health monitoring device. Ahealth monitoring system using LabVIEW is developed forwireless transmissionofheart rate and oxygen saturation percentage to the watch using RF telemetry.

II. METHODOLOGY Figure 2 shows the block diagram of the proposed watchbased wireless health monitoring system which consists of an ECG processing circuit system, a pulse oximeter module,

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a computer transmitter station and a receiver station which is the eZ430-Chronos watch. The ECG electrodes will acquire heart signals while the pulse oximeter module will get the oxygen saturation signal from the patient. The analog inputs (ECG signal) and UART input (oxygen saturation digital signal) will then be integrated to a computer and processed by LabVIEW. The process includes the calculation of heart rate and percentage of oxygen saturation and the wireless data transmission to the receiver station (sport watch).

Pulse oximeter module: The digital signal from the module is connected to the computer for data integration using UART. LabVIEW (computer): The ECG signal is processed by a system developed in LabVIEW to calculate and display the value of heart rate and oxygen saturation. It is also programmed to send the packets of heart rate and oxygen saturation data from the LabVIEW transmitter station via RF module (USB access point), which is wirelessly paired with the existing transceiver in the eZ430-Chronos watch. B. Receiver Part

ECG electrodes

Pulse Oximeter Module

eZ430-ChronosWatch: The eZ430-Chronos sport watch can be reprogrammed using Code Composer Studio software, which can be written in C language, to displaythe received heart rate and oxygen saturation data from the LabVIEW transmitter station whenever required. Simplified programming and debugging can be achieved by using the eZ430 USB emulator which comes with the Chronos sport watch, (refer to Figure 3).

ECG electrodes and pulse oximeter worn by a patient. ECG amplifier circuit

UART

DAQ Card

LabVIEW (computer)

Fig. 3 USB emulator for watch programming and debugging USB RF module

III. RESULTS

(Transmitter Station)

Figure 4 shows the sample of an amplified ECG signal from the ECG amplifier circuit which is connected to the ECG electrodes attached to the patient’s chest. To verify the accuracy of the program developed in LabVIEW, a patient

WIRELESS TRANSMISSION

Receiver station

Fig. 2 Block diagram of wireless health monitoring system A. Transmitter Part ECG Signal Processing Circuit:In this system, the ECG signal is acquired from the electrodes attached to the body. The small ECG signal, which is usually in the range of mV is amplified and connected to the computer via the input port of the Data Acquisition (DAQ) Card.

Fig. 4 GUI (Graphic User Interface) for heart rate transmitter station

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EZ430-Chronos Watch as a Wireless Health Monitoring Device simulator, a device that mimicshuman ECG signal is used as a reference. The heart rate calculation developed in LabVIEW was proven to be reliable as it gives the same heart rate value that is set at the patient simulator. A. Transmitter Station The developed LabVIEW program is able to send the calculated heart rate and oxygen saturation data in real time continuously to the eZ430-Chronos watch via a serial port through the USB RF module. The LabVIEW program(in run mode) will simultaneously interpret the input data and transmit them wirelessly to the watch.

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been developedis restricted to only patients that are critically ill and are not able to walk around. The patient being monitored must be attached to the computer/machine for continuous monitoring, which is a disadvantage in mobility of the system. For future development, we are upgrading the wireless watch monitoring system to a wearable miniature processing circuit that is able to transmit three inputs (heart rate, oxygen saturation and temperature) or more to the watch wirelessly and controlled by a PIC16 microcontroller, a smaller processor compared to a computer. The miniaturize circuit can be placed into a sling bag to be worn by the patient and is more portable.

B. Receiver Station

V. CONCLUSION

Figure 5 shows the received heart rate valueafter the data is transmitted from LabVIEW.One additional feature developed using the watch is the alarm mode. The alarm mode will alert the user who is wearing the watch if the heart rate and oxygen saturation data of the patient is out of normal range. The abnormal range of data can be set from the LabVIEW front panel.

A wireless communication can be established between the RF module connected at the computer (transmitter station) and the eZ430-Chronos watch (receiver station). The heart rate value calculated from the ECG signal and the percentage of oxygen saturation acquired from a patient can be wirelessly transmitted and displayed at the watch. The wireless health monitoring system enables the user to monitor the patient’s heart rate and percentage of oxygen saturation remotely within the wireless protocol range.

ACKNOWLEDGEMENT

Fig. 5 The transmittedsample heart rate of 60bpm and 120bpmdisplayed on the watch

The author would like to sincerely thank the Ministry of Higher Education Malaysia for funding support and Universiti Teknologi Malaysia (UTM) for the facilities and equipment provided for this research.

REFERENCES IV. DISCUSSION One of the advantages of the developed wireless health monitoring system is that the person who is responsible to monitor the patient’s condition can do it while doing other activities and be alerted instantly when the alarm mode is activated.. It would also be useful in clinics where nurses can be alerted and attend to the patient immediately when the patient’s heart rate and percentage of oxygen saturation is out of the normal range. The disadvantage of the wireless transmission is that the RF access point only transfers data up to 20m of distance from the watch. Currently, the monitoring system that has

1. Pettis, K., et al., Evaluation of the efficacy of hand-held computer screens for cardiologists' interpretations of 12-lead electrocardiograms. American Heart Journal, 1999. 138(4): p. 765-770. 2. Taylor, J., et al., Towards multi-patient leadless and wireless cardiotocography via RF telemetry. Medical Engineering &Physics, 1999. 20(10): p. 764-772. 3. Chen, F., et al., SmartPad: A Wireless, Adhesive-Electrode-Free, Autonomous ECG Acquisition System. 30th Annual International IEEE EMBS Conference Vancouver, British Columbia, Canada, August 2024, 2008. 4. Ming, H., Z. Yajun, and H. Xiaoping. Portable ECG Measurement Device based on MSP430 MCU. 2008. 5. Incorporated, T.I., eZ430-Chronos development kit. 2009 6. Zhou, Z., Secure Wireless Door Lock. EZ430-Chronos Projects2010. https://ziyan.info/2010/01/secure-wireless-door-lock/.

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