DESIGN AND CONSTRUCTION OF A PULSE-RATE MEASURING DEVICE BY OBAITAN ANNE-MARIE 2004/18843EE A Thesis submitted to the Department Of Electrical And Computer Engineering, Federal University of Technology, Minna, In Partial Fulfillment for the Award of Bachelor Of Engineering (B.Eng.) Degree. December, 2009... : I
DEDICATION dedicate this project to God Almighty who grants wisdom, and to my entire family for all their JUIl'VV.lo., care and understanding. To my very dear friends who have always been there for me,u.j.v... thick and thin. To my Lovely Mother I say thank you. I love you all. ii
DECLARATION Q!2 "~ ~_rl~=~~~_.: declare that this work was done by me and 'las never been presented elsewhere for the award of a degree. I hereby relinquish the copyright o the Federal University of Technology, Minna. OBAITAN ANNE-MARIE Mr. J.A. Ajiboye Signature and Date) (Signature and Date) J"lame ofh.o.d) (Name of Extemal Supervisor) ~ ( (\M.{},M ~ Qc, t \) ) ~-~~-~----l--- ~ Signature and Date) (Signature and Date) iii
ACKNOWLEDGEMENT utmost appreciation goes to God Almighty for his mercy, protection, provision and Loving,;an~:lI1e:ss throughout my stay in Federal University of Technology Minna. am specifically indebted to all the staff in the Department of Electrical and Computer ngineering for the great knowledge impacted into my life during my years of study. am extremely grateful to my project supervisor Mr. l.a. Ajiboye for his intellectual supports vice and constructive criticisms. Am also very grateful to the lab technologists especially Mr. B.A. Olawuyi. I remain highly indebted to my Mother Mrs. M.S. Obaitan and my sisters Peace, lizabeth and Stephanie Obaitan for all their supports both financially and otherwise during the ear of the program. Finally my thanks go to my friends, Omolara Akinyeye, Oladoyin Elujoba, bimbola Ajagun, Afoma Onyemelukwe, Yakubu Agoh, Yvonne Achema, Chiemela Akoma, ~neka Ndiwe and so many others for their unending support. God bless you all. iv
ABSTRACT The pulse rate measuring device is an electronic device that observes or monitors the eartbeat or pulse rate of the heart, and gives an output in form of a visible signal. It consists of input, a two stage gain amplifier, a comparator and a microcontroller. The output is displayed or observed through the liquid crystal display (LCD).The pulse rate monitor has a light source for illuminating the skin tissue. The infra-red sensor and transmitter used for signal detection and transmission, functions via the changes in the arterial blood flow as a result of expansion and contraction of the heart during pumping of blood in the body, on exposure to the ambient light. The output of the infra-red device is amplified, and then compared with a reference voltage by the comparator. The output from the comparator is then fed into the microcontroller which in turn feeds the liquid crystal display unit as the output. The output shows the number of eartbeats measured normally in beats per second (BPM). v
TABLE OF CONTENTS Title Page Dedication ii Declaration 1ll Acknowledgement IV Abstract V List of Figures IX Chapter one: General Introduction 1.1 Introduction 1.2 Definition of project 1.3 Aims/objectives of project.4 Methodology.5 Project Synopsis 1 3 3 4 4 Chapter Two: Literature Review l.1 Historical Background 6 _.2 The input device (The infra-red device) 8 2.3 Amplification of signal 8 Z.4 Pulse Detection 10 vi
2.5 Limitations 10 Chapter Three: Design and Implementation 3.1 Hardware and software Design considerations 11 3.2 Power Supply 13 3.3 Input Stage 16 3.4 Amplification 17 3.5 Comparator Stage 20 3.6 Micro-controller 21 3.9 Display 24 3.8 Implementation 27.9 Circuit Diagram 28...,....,.... Four: Construction and Testing.1 Construction 29 31 31 Problems Encountered 31 32 vii
33 I-UQIV\,.,l Five: Conclusion and Recommendation 1 Conclusion 34 Recommendation 35 36 viii
LIST OF FIGURES ig 1 A typical ECG wave form ig 2.2.2a An amplifier without feedback 'ig 2.2.2b An amplifier with feedback ig 3.1 Block Diagram ig 3.2 The Power Supply Unit ig 3.3 The infra-red sensor and transmitter ig 3.4a LM358 pin out Diagram 'g 3.4b Op-amp in its inverted mode 'g 3.5 Comparator circuit 'g 3.6 The PIC 1 6F84 microcontroller g 3.7 Character LCD type HD44780 pin diagram g 3.8 The circuit diagram g 4.1 Printed Circuit Board ST OF TABLES ble 1 Character LCD pins with 1 controller ble 2 Character LCD pins with 2 controller ix