heart rate

OBJECTIVE

    1.      To design and construct the Heart Rate Monitor in 8051 micro controller.   

    2.      To interface the Heart Rate Monitor with c language.

    3.      To detect pulse of heart rate in human.

DESCRIPTION OF HEART RATE MONITOR

The system is design to be use with 9V DC power supply. The system is divided into 3 different part which is the input module, the micro controller unit and the output display unit.

      1.      The Input Module

This consist of amplification circuit and IR pair. The two major component of this two are:-

Figure 1: LM324

It is a Dual-in-Line Packaged Quad processor which consists of four independent, high gain, internally frequency compensated operational amplifiers which are specifically designed to operate on single power supply over a wide voltage range. Three of them have been used to amplify the signals from the IR.

·         IR pair

Figure 2: IR pair

An IR transmitter and receiver pair is used. Here the transmitter transmits the signal through the finger which is placed over it. Whenever there is an increase in concentration of red blood cells in the vein, the signals detect by bouncing back to the receiver IR. This way each time the blood is pumped throughout the body, a localized area of the human body will help to detect it. This signal is then send to the micro controller unit. 

2.      The Micro controller Unit

An Intel 8051 micro controller is used as the main decision making processor in the system. Its architecture includes CPU, RAM, ROM, I/O, Interrupt logic, timer, etc in a single processor. It has a 8 bit accumulator and 8 bit ALU thus making it an 8 bit processor. This unit also uses a crystal to generate clock frequency. This crystal has been specifically chosen to have 11.0592MHz of frequency and the timer and delay programs have been generated taking this into consideration.

3.      The Output Display Unit

This module consist of liquid crystal display (LCD), due to the use of a micro controller to calculate and display the heart rate, it was decided that a LCD   module would be the most flexible way of displaying this numerical output.

LIST OF COMPONENT

1.      Strip board

2.      AT89C52 40 pin IC

3.      LM324N IC

4.      Turn-pins IC socket 40 pins

5.      Crystal 11.0592 MHz

6.      Capacitor 

7.      Resistor  

8.      Push button switch

9.      LED

10.  Voltage supply

11.  LCD display

12.  Diode

13.  IR sensor

Figure 5: Simulation running

The heart rate signal is obtained by LED and LDR combination, pulse from hands interrupts the light reaching the LDR and this signal read by microcontroller. The LED needs to be bright as maximum light must pass spread in finger and detect by detector, when the heart pumps a pulse of blood through the blood vessels, the finger becomes slightly more opaque and so less light reached the detector. With each heart pulse the detector signal varies. This variation is converted to electrical pulse. This signal is amplified and triggered through an amplifier and the result will displayed on LCD. 

CONCLUSION

This Heart Rate Monitor can be used by many people to measure their heart rate, especially to the person who like to exercise, with this heart rate monitor they can measure their heart rate. The result and output is a simple count that depends on the IR sensors. However there are a few disadvantages of the system and its specifications. The system considers the environmental factors and other parameters while checking the sensor value. This error may be generated. This error can only be avoided if the calibration of the system has been done correctly in the environment where the system is being used. The IR sensors correctly can detect changes in the blood flow thus making sure that the increment operator in the microcontroller program code work efficiently to produce the final result. It is also cost effective and easy to build. There is very little requirement of understanding the system before using it, thus making it easy, helpful and less time consuming.

Code Source
  https://drive.google.com/open?id=0B2VME2Xn52GwU0QzZTdwV2VIbGs

REFERENCE

1] R.S.Khandpur, “Handbook of Biomedical Instrumentation”, 2nd edition, Tata-Magrow-Hill Publication,2003, New Delhi

[2] John Webster, “Medical Instrumentation: Application and Design”, 3rd Edition, Wiley India Pvt. Ltd, July 2009

[3] Richard Aston, “Principles of Biomedical Instrumentation and Measurement”, Merrill Pub Co. , 1990

MUHAMAD AMIRUL BIN NAZRI                                                            51211215021

MUHAMMAD IMRAN BIN MOHAMAD                                                 51212114026