Introduction


It is a common notion that stress result into diseases and aging that disturbs the normal functioning of the body. ECG is the graph of bioelectric signals generated by depolarization and repolarisation of the heart says SERINDIP (2007). This shows how important the heart rate measures which can guide in finding various factors of a human body.


Heart rate is the number of heart beats per minute, typically expressed as beats per minute. Our normal pulse rate is ~72/min and it is higher or lower when one is unwell. Generally we think that our heart beats at a normal rate. Doctors describe the normal electrical activity of the heart as "regular sinus rhythm". But, sometimes the heart beat of a healthy person fluctuates in an irregular manner even at rest. This article is concerned about the detection of human heart beat rate and to display the same in the 16*2 alphanumeric LCD display. For the detection of heart beat sensor is developed in order to give a binary output according to the heart beat.


Objectives


The need for smart textile and E-textiles are much growing due to its multi functionality in applications. Having this priority in mind an E-Suit is designed to detect the heart rate of the person and its efficiency is been tested.


Methodology


1.     Selection of Microcontroller

8051 series microcontroller is selected, as the cost of the microcontroller is low. Moreover, it is widely used in the market and the efficiency of microcontroller is high. The microcontroller is programed according to the required function.



 


2.     Selection of Compiler

'Keil u vision' is used as the compiler, using this software the coding is done in embedded c language, the software itself converts it into assembly language and the final output is obtained as intel hex files. Then the hex file is burned to the microcontroller with the help of 8051 usb programmer with the proload software.




3.     Selection of Simulator

Proteus isis simulator is used to see the functioning of the project in realtime. The required microcontroller is selected, and the required electronic components are selected, the wiring is done and the hex file is loaded into the microcontroller. Then the simulation is allowed to run and the functioning is seen through the screen.


 


4.     Selection of Program loader

Preload software is selected to burn the intel hex files to the microcontroller. The USB programmer will be detected by the software and the microcontroller can be erased and the desired program is loaded to the microcontroller.




5. Board construction procedure

        The microcontroller base is soldered in the multipurpose board.

        The microcontroller is placed in the base.

        The pull up resistors is soldered into the first port of the microcontroller.

        The 7805 regulator along with capacitor is soldered.

        The LCD wires are soldered to the PCB.

        The crystal and capacitor and minor components are attached to the PCB.


6. Garment design procedure

        To design a garment for embedding the device.

        Comfort of the garment must be given main importance.

        Welcrow is used instead of buttons.

        Lining material is used to cover the device and wires.


 



7. Garment construction procedure

        Organic cotton is selected for the garment construction.

        Low neck, sleeve-less garment pattern is created.

        The device is attached and the sensor wire is infused in the garment.

        Lining material is used to cover the device and wires.


Results and discussion


The designed product is been subjected to following analysis in order to check its efficiency and extended product life.


1.      Working voltage range of the device.

2.      Sensing range of the sensor.

3.      Life time of the battery used for the device.


The above listed have been tested and various changes have been made to improve the efficiency and the life of the product.

 

1. Working voltage




The above chart shows the range of working voltage of the microcontroller. So when the voltage drops below three volt the device does not work. But when the voltage exceeds five volts, the device gets damaged. In order to get a better working environment, I have used the 7805 voltage regulator. This voltage regulator keeps the current within the range of 4.5 to 5 volts DC. The dimensions of the regulator are 100*45*10 mm.


 

2. Sensing range




The above chart shows the minimum and maximum range of heart beat sensing. The average human heart beat rate is from 7 to 200. So the device is capable sensing the human heart beat rate in all ranges, so the output obtained is accurate in all ranges.


3. Life of battery




The above chart shows the life time of the battery used in the project. When the same battery is used for working of 10 devices the battery life is minimum three months. So when the battery is used for single device alone the battery is capable of withstanding more than a year. Hence, frequent change of battery is not required.

 

Conclusion


Micro-controller is used in many fields; it is even used in design and fabrication of biomedical equipments. For example, the microcontroller (8051) is used to develop the heart beat monitoring system. Then digital pulses or TTL pulses are fed into the external interrupt of the micro controller 8051. With the help of this software, one can count the pulse rate and result is displayed on LCD (2 line 16 characters). The device is been invented and tested for its ability of the detection of heart beat rate and it seems that the process of finding the device has been successfully brought out. The device has shown that:

        The device senses the heart beat rate.

        The heart beat rate is displayed in the LCD.

        The battery life is studied.

        The sensing range of the heart beat is studied and the device is capable of detecting minimum and maximum range of human heart beat.

        The working voltage range of the device is analysed and voltage regulator is used to improve the working efficiency and also the product life.

        The device does not disturb the comfort of the wearer.

        Thus, a new device is been introduced and transformed into a garment which can be introduced in the market for a pre-production with a good product planning.


References:


1.      Regulation of Human Heart Rate. Serendip. Retrieved on June 27, 2007.

2.      Thelancet.com

3.      Kolata, Gina (2001-04-24). 'Maximum' Heart Rate Theory Is Challenged. New York Times.

4.      Robergs R and Landwehr R (2002). "The Surprising History of the "HRmax=220-age" Equation" . Journal of Exercise Physiology 5 (2): 110. ISSN 1097-9751. Retrieved 4-1-09.

5.      Microcontroller Based Heart Beat monitoring and Alerting Systen, Mayank Kothari, IOSR Journal of electronics and Communication Engineering(IOSR-JECE), ISSN:2278-8735.Vol;(,Issue!,Ver;1,Jan 2014,p:30-32

Mrs. E.Devaki is Assistant professor in Department of costume design and fashion, PSG college of arts and science, Coimbatore.