Heart Rate Monitor and Data Acquisition System

1
Heart Rate Monitor and Data Acquisition System

• Senior Design Project
• University of Illinois
• Bill Leece and Sofoklis Nikiforos

2
Introduction

• Design an ECG
• Display heart beat
• Display heart rate
• Count Calories

3
Motivation

• Interest in Digital and Analog Electronics
• Interest, but not necessarily experience, in
  Bioengineering
• Bill will be doing circuit design for pacemakers
  with Medtronic in the fall
• Nick is considering Bioengineering courses

4
Overview

• Design considerations
• Hardware
• Software
• Strengths and Weaknesses
• Cost Analysis

5
Design Specifics

• Biopotential electrodes
• Amplifier circuit
• PC interface via DAQ
• LabVIEW software

6
Block Diagram
7
Hardware Diagram
Right Leg Circuit
Input from Right Leg
Pre Amp
Bandpass Filter and Power Amplifier
Input from Electrodes
Output to PC
8
ECG Characteristics

• Preamplifier
• Low gain
• Eliminates unwanted signals (interference)
• Driven Right Leg Circuit
• Minimizes interference
• Electrically safe for patient

9
ECG Characteristics (Cont.)

• Power Amplifier and Bandpass Filter
• Industry standards are set at 0.05Hz-150Hz
• Amplification is essential in order to record the
  signal to a recorder
• Output to PC
• The analog signal is sent to the PC via the DAQ
• LabVIEW software performs signal analysis on data
  it receives from the DAQ

10
LabVIEW Software

• Graphical Programming Language
• Useful for Data Acquisition
• Easy to Debug

11
LabVIEW Hierarchy
12
Heart Rate Monitor Front Panel

• Enter age, weight, and resting heart rate
• The Heart Rate Monitor Front Panel VI outputs the
  users maximum and minimum target heart rate
  needed for maximum calorie burning during
  exercise
• The age and weight data is then sent to the ECG
  subVI

13
ECG

• Displays ECG data
• User controls sampling rate
• Displays BPM and calories burned
• Problems encountered

14
Timing Circuit

• Used to keep time for BPM calculations
• Makes sure that the program keeps real world time
• Problems encountered

15
Counter

• Counts rising edges of ECG pulse for BPM
  calculations
• Uses signal averaging to accurately count noisy
  signals
• Problems encountered
• Now lets look at a cost analysis of this project

16
Prototype Cost Analysis

• Case (Chassis) 10
• Printed Circuit Board 100
• OpAmps 5
• Resistors, Capacitors, Etc. 5
• Software (LabVIEW 5.1) 995
• NI-DAQ 795_
• Total Parts Cost 1,810

17
Conclusion

• Strengths and Weaknesses
• Areas that could be improved
• Questions?