A Color – Coded Bracelet Modeling System to Measure Heart Rate Pressure and Drug Level for Sports Application

A Color – Coded Bracelet Modeling System to Measure Heart Rate Pressure and Drug Level for Sports Application

Department of Bio-medical Engineering, Alpha College of Engineering, Chennai

Abstract

This paper presents a current invention for monitoring the athletes heart rate. A bracelet with 3 LEDs is designed as a wrist heart rate monitor. In the sports field, the Bracelet is used to find the heart rate (because the range of heart rate should be compatible with the exercise done by an athlete to get an optimum exercise) and also to find people who tak e drugs .The heart beat sensor in the bracelet is used to find the heart beat level, pressure sensor is to check the blood pressure level and drug detection sensor is to detect drug consumption. The sensor output is processed by the controller and received by the receiver through Zigbee. The processing software is a user friendly, and it provides data acquisition, monitoring and recording. And hence the software displays the heartbeat, pressure and the intake of drug level. This will be very helpful for athletes and coaches to monitor the fitness level of athletes and regulate their exercise training regime in a more effective and safer manner.

1. INTRODUCTION

   Nowadays, the use of a heart rate monitor is very common and not mere ly used at the hospitals as a monitoring system for patients. Generally, heart rate monitor was used by a person who cares about their heart to ensure that they have a normal heart rate. The early detection of the abnormal heart rate can help to prevent from the serious disease. In the sport field, the heart rate monitor is needed to determine the range of heart rate. This range of heart rate should be compatible with the exercise done by an athlete to get an optimu m e xe rc ise to prevent from serious injury. Such digita l display of target heart rate did not provide for ease of reading the display under the most conditions of use, particularly when the user is exercising vigorously [1, 4]. This paper proposed an innovation to respond to this problem by providing a novel

   wearable bio med ical signal sensor device for monitoring heartbeat conditions at home easily, which displays the heart rate by glowing of 3 diffe rent LEDS and enabling a user to tell at a brief glance, whether they are e xerc ising at a suitable intensity and the coach to identify the sports person who have in taken drug or alcohol. The proposed innovation will be progra mmed to auto matica lly suggest the user about their health conditions. The work will be focused for sport training application [2]. This Prototyping can monitor appropriate heart rate while performing an e xerc ise by sending feedback to the user via the specific color (LED) and to the coach via the wire less protocol. The Zigbee wireless protocol is chosen as a transmission mediu m because it provides a small volume, high e xpansion, low powe r consumption, stylization and two-way transmission [3] co mpared to Bluetooth [5].

   In this research work, we developed a group of sensors for measuring heart beat rate, pressure level and drug level with real-t ime monitoring system based on Zigbee wire less network. The heart beat data measured by the sensor is processed by the ADC in the microcontrolle r that data was read every second and stored on microcontroller. The data from mic rocontroller unit was sent to base node via Zigbee wireless network and stored on data-logging PC. Mic rocontroller hard ware and Zigbee module are packed in suitable case and can be worn on the sports persons wrist.

   The physiological para meters that are monitored with the proposed wearable bracelet are electrocardiogra m (ECG), heart rate (HR) derived fro m ECG signals by determining the RR intervals, body temperature, respiratory rate, and three a xis move ment (accele ration and position) of the subject measured using an accelerometer. In order to design and construct the signal acquisition circuits efficiently and simply, modula r design concept is adopted in this research. Three basic high quality and fle xib le modules for signal conditioning are designed and assembled together for satisfying each

   sensor. Human b io medica l para meters can be registered and analyzed continuously during homework act ivities .

   The rest of the paper is organized as followed. Section 2 describes about the proposed systems hardware design. Section 3 describes about the data transmission based on Zigbee wire less sensor network. In section 4, the software design of proposed system is e xpla ined and the last section is about the conclusion.

2. HARDWARE D ESIGN

   The heart rate monitoring brace let model main ly consists of two subsystems: first, a wearab le data acquisition hardware, where the sensors for acquiring the biomedical para meters are integrated and transmitted to the receiver through Zigbee, and secondly, a remote monitoring station placed separately.This system as a whole is used in sports application.

   The hardware design main ly consists of three sensors namely: Drug detection Sensor, Heartbeat Sensor, Pressure Sensor. These sensors are connected to the mic rocontroller. This microcontroller is further connected to three diffe rent color LEDs. The transmission medium used here is zigbee wire less protocol [Fig 1]

   1. Transmitter Module

      1. Heart Beat Sensor

         There are three sensors used in the transmitter module. They are the, Heartbeat Sensor, Pressure Sensor and Drug detection Sensor. The heart beat sensor used here is 1157 Hea rt beat sensor. This sensor is designed to give digital output of heart beat when a finger is placed on it. When the heart beat detector is working, the beat LED flashes in unison with each heartbeat. This digital output can be connected to microcontroller direct ly to measure the Beats per Minute (BPM) rate. It works on the principle of Light modulation by blood flow through finger at each pulse.

         The pin details are the following: PIN1-power

         supply positive input, PIN2- active high output and PIN3- power supply ground [Fig 2]. Specifications are Operat ing Voltage is +5V DC regulated, Operating Current is 100 mA , Output data Level is 5V TTL level , Heart Beat detection is indicated by LED and Output High Pulse Light source used is 660n m Super Red.

         Maste r Controller

         ZIGBEE

         PC Front end display

         P I C

         Channel 0

         Pressure sensor

         Heart beat sensor

         1 U

         Channel 1

         6

         F A

         8

         Drug detection sensor

         7 R

         Channel 3

         7

         Battery Voltage

         A T

         Channel 4

         ZIGBEE

         RS232 Driver

         Master Controller

         Fig.1 BLOCK DIAGRAM

         Green LED

         Yellow LED

         Red LED

         Fig.2 HEART BEAT SENSOR

      2. Pressure Sensor

         High blood pressure, also known as hypertension, occurs when the force (or pressure) of blood against your artery wa lls is too great, causing e xcessive strain on your blood vessels. This condition is dangerous because its damaging effects accrue over time and may not become apparent until an individual's blood pressure is shockingly high. This is why hypertension is sometimes known as a "silent kille r."

         Power supply

         The sensor can be used to detect pressure in a range of situations from air press ure in tyres to blood pressure. The capacitance-type pessure sensor is generally characterized by high sensitivity and low current consumption and this product also minimizes the influence of temperature changes on pressure detection. Due to the ability of the ceramic packaging to withstand a wide range of temperatures, it can even be used in the volatile automotive environ ment. The sensor detects air, blood and other pressures by means of changes in

         capacitance. Pressure is detected when pressure changes cause the me mbrane on the moveable electrodes known as a diaphragm to fle x, the capacitance between the fixed electrodes changes and the degree of this change is converted into an electrica l signal. A persons blood pressure is usually e xpressed in terms of the systolic pressure over diastolic pressure and is measured in millimet res of mercury (mmHg)

         Fig.3 PRESSURE SENSOR

      3. Drug Detection Sensor

      The drug detection sensor used here is Gas sensor MQ-303A. It is a tin di -o xide semiconductor gas sensor which has a high sensitivity to alcohol with quick response speed. This model is suitable for alcohol detection such as portable drug detection or breath alcohol checker. The pin details are the following: PIN1-power supply positive input, PIN2- active high output and PIN3- power supply ground [Fig 4]. Specifications are Operating voltage is dc voltage less than 6V, resistance is 4.5 ± 0.5, current is less than 13mA , Power dissipation is less than 10mW.

      Fig.4 DRUG DETECTION SENSOR

      The change of the sensor resistance (R ) is obtained

      S

      as the change of the output voltage across the fixed

      or variable resistor (R ). In order to obtain the best

      L

      performance and specified characteristics, the

      values of the heater voltage (V ) circuit voltage

      H

      (V ) and load resistance (R ) must be within the

      norma l testing , the sensor shall stabilize and enter into norma l working conditions quickly.

   2. DATA PROCESSING

      The mic rocontroller used here is PIC16f877a .It is a 40 p in microcontrolle r with 5 I\O ports, 10 b it ADC up to 8 channels, three 16 bit timers and 2 comparators. Operat ing speed: DC 20 MHz clock input DC 200 ns per instruction cycle. It has 8K x 14 words of Flash Program Me mory, 368 x 8 bytes of Data Me mory (RAM) and 256 x 8 bytes of EEPROM. 5 volt dc supply is given to the heart beat sensor, pressure sensor, drug detection sensor. Primarily the heart beat sensors output is given to the PIC16F877A .This mic rocontroller has built-in analogue to digital converter (ADC) and RS-232 serial co mmunication interface. The flash program me mo ry allows in-circuit reprogra mming of the firmware. A lthough the ADC has a 10-b it These heart beat signals are in turn converted from analog to digital form in this built in ADC. Then this converted output is temporarily stored in RAM me mo ry of PIC16F877A.A fter a small delay of 3ns the pressure sensor output is given to the microcontroller where these pressure signals are in turn converted from analog to digital form. Then this converted output is temporarily stored in RAM me mo ry of PIC16F877A. Again After a small delay of 3ns drug detection sensor output is given to the mic rocontroller where these signals are in turn converted to digital form. Then this converted output is temporarily stored in RAM me mory of PIC16F877A .

      The heart rate is calculated using the equation as followed

      BPM (Beats Per M inute) = 60 \ period (second) (1)

      Norma lly with the help of the Age Pred iction formula (2) and (3) the indiv iduals heart rate is determined. In itia lly, microcontrolle r will ca lculate the heart rate ma ximu m (HR ma x) and then determine the target heart rate zone desired by user. This HR ma x value is obtained by inserting the user age and gender informat ion. The formula used to calculate the HR ma x is presented in equation

      (1) and (2) respectively for ma le and fe male .

      Male: HR ma x = 206.9 – (0.67 x age) . (2) Fe male : HR ma x = 212.9 – (0.67 x age) (3)

      C L

      range of values given in the standard operating conditions shown in the Specification table on the next page. Genera lly, the sensor enters into normal working conditions after several minutes preheating, If you connect the sensor heater with a high voltage 2.2 ± 0.20V for 5-10 sec before

      Then, the following equation is used to calculate the target heart rate (THR) zone.

      THR = HR ma x x % intensity (4)

      After this Target heart rate value is found based on the Age Prediction formu la (2) and (3) pred iction

      equations then the heart rate and the pressure rate for each second of an individual is found. The calculated Target heart rate and the measured heart rate are co mpared. Then the heart rate for that second is found to be normal, low o r high in the PIC16F877A microcontrolle r. If the heartbeat value is normal when compared to the target heart rate then the Ye llo w LED glows in the transmitter section, in the wearable bracelet. And if the heartbeat value is low when co mpared to the target heart rate then the Green LED glo ws. And if the heartbeat value is high when compared to the target heart rate then the Red LED glo ws. By this range of heart rate, it should be compatible with the e xerc ise done by an athlete to get an optimu m e xerc ise to prevent from serious injury.

   3. Receiver Module

      MCU receives the sensors data in area via the Zigbee network, which Zigbee base node module was set in coordinator node. The data fro m every node are stored in the memory of M CU and subsequently transferred to a computer by UART every second. Data from the base node are sent to a computer using USB to serial converter. To add more end nodes into this network, the new nodes will send a request to the router or base node and wait for a reply. A PC is working as a data logger in this network because a large nu mber of spatial and temporal data can be stored for further analysis by user. The user can also access current heartbeat data from a base-PC co mputer.

3. DATA TRANSMISSION

   1. Zigbee Wireless Module

      Various wire less network technologies have been used in health monitoring system. This system is based on Zigbee wireless standard. Zigbee is fa mous for low cost, low power consumption and fle xib le network topology. All wire less sensor hardware operates upon a short-range communicat ion between 40 to 120 meters. The ZigBee based on IEEE 802.15.4 standard, defines the characteristics of the physical and the medium access control (MA C) layer for the low power of personal area network (PAN). The three frequencies was support by ZigBee physical layer:

      2.4 GHz ISM band (world wide), 915 MHz ISM

      band (America), and 868 MHz band (Europe). In this work, we used ZigBee module fro m Ma x stream wh ich provides 16 of personal area network ID (PAN ID) and used frequency of 2.4 GHz. This Max streams Zig Bee module.

      Fig.5 Zigbee Module with Mic rocontroller module

      Since co mmunication of the micro-controller and PC with the Zigbee transceivers is transparent byte- oriented data stream, data is packetized before being sent to the RF module for wire less transmission and de-packetized after receiving them fro m the transceivers. Each packet consists of eight bytes. The first byte is a header and the following seven bytes are data. To distinguish the header fro m the fo llo wing data, the mos t significant bit of the header is set to one. The first most significant bits of the following seven data bytes are shifted to the seven unused bits of the header. Then they are cleared as zeros. At the receiver side, a header can be detected when the mos t significant bit of the received byte is one. Following the header are the seven data bytes which can be recovered easily by shifting the seven bits from the header back to the most significant bits of the seven data bytes.

      The transceiver's interface is RS-232 style with standard CMOS signal leve ls, which makes the electronic interation with the micro -controller and PC much easier through UART. Hence the heartbeat, pressure level and the intake of drug is acknowledged fro m PC wh ich can be seen by the coach during sports activities.

      OBS ERVATION

      Le d Col or	Target zone	Trai ning Recomme nde d
      Yellow	Norma l( 72 BPM)	Fit person, maintain the activity level.
      Green	Low(60- 70 BPM)	Unfit person, increase the activity level.
      Red	High(>7 2 BPM )	Indicates the person is in abnormal state, recovery and cool down e xerc ises should be done

      TA BLE I

      Different Co lor of LED Based On Heart Rate Zone

      Le d Col or	Pressure level	systolic (mmHg)	di astolic (mmHg)
      Yellow	Norma l	90 – 130	60 80
      Green	Low	< 90	< 60
      Red	High	>140	> 90

      Reception, interpretation and e xecution of commands fro m the seria l co mmun ication interface.

   2. Application Program Design

      TABLE I

      Diffe rent Color of LED Based On Blood Pressure level

      Sensitivity of Alcohol sensor

4. SOFTWAR E DESIGN

   The software can be separated into two parts: the firmware running in the micro-controller on the front end analogue circuit board and the application program running on PC.

   1. Firmware Design

      The program e mbedded on the mic rocontroller is written in Embedded C. The program contains the following:

      Conversion of analogue signals (heartbeat, pressure rate,drug level) to digital values.

      Heartbeat detection. Target Heart rate and Maximu m Heart rate ca lculation.

      Analyzing whether the Heart rate is norma l, low or h igh.

      Indication of the respective LEDs according to the Heart rate at that instant.

      Packetizat ion of the collected data and the transmission of them through the serial communicat ion interface.

      On the computer side, all sampled physiological data are displayed and saved to a file on hard d isk of PC in real-time . The application progra m running on PC is written in Microsoft Visual C++ for Windows. The progra m contains the following: the main part handles the data collection. It collects the data received by RS232 seria l co mmun ication port from one of the Zigbee transceivers connected to it. The received data is stored in a data buffer and a data buffer block. Then that data is obtained fro m the data buffer and displays them on the PC screen. There are two data buffer blocks used alternatively. When one of them is full, the saving thread will be created to save it to a file on the hard disk. The program has been running on a computer without losing any data.

      Fig. 6 Model of Wearable Heart Rate Monitor with a Pulse Oximeter

      Fig.7 FLOWCHART

5. CONCLUSION

The portable color coded bracelet modeling system is Designed as a wearable bracelet which is non- invasive, lightwe ight and easily worn so that the athlete feel co mfo rtable and will not impede their activities. This device also gives an advantage to coach to easily get the information about athlete heart rate, blood pressure and the in-taken drug level by only mon itoring the LED indicator on bracelet wearing by athletes

Future works will be focused on reducing the size of LED strips/bracelet to be worn as a wrist band and can be designed for low cost with less power consumption so can be comfortably used in daily life.

REFERENCES

1. N.H Mahmood, Uyop, N.Zulkamin, Ek -Che Harun, M.f.Kamarudin, A.linoby, LED Indicator for Heart Monitoring System in Sport Application, 2011 IEEE 7th International Colloquium on Signal Processing and its applications.

2. N.Watthanawisuth et al Wireless Wearable Pulse Oximeter for Health Monitoring using ZIGBEE Wireless Sensor Network, ECTI-COM 2010, pp.575-579.

3. Edwards C Health Care hi-tech lifelines, Journal of Engineering & Technology, 2008. Volume ¾ pp.36- 39.

4. A.Linoby Color-coded Heart Rate Monitoring Bracelets (COBRA) to guide specific Exercise Training Intensity,RMI-UiTM(patent),2009,pp.1-12.

5. Chenz,Hu,C; liao J, Liu S, Protocol architecture for Wireless Body Area Network based on nRF24L01, IEEE International conference on Automation and logistics,2008.pp.3050-3054.

6. Daoming Z. Branko C Monitoring Physiological Signal During Running Exercise,Proc.of 23rd Annual EMBS Int.Conference,2001,pp.3332-3335.