Electrocardiograph
Wei Lin
Department of Biomedical Engineering
Stony Brook University
Instructor’s Portion
Summary
This experiment requires the students to build an electrocardiograph based
on the previous projects of instrumentation amplifier and high-pass/lowpass filters. The students are required to build a sub VI that can measure
the heart rate from the collected ECG signal.
Uses
This lecture applies to all courses of virtual instrumentation.
Equipment List

Computers

LabVIEW 8.6

NI-ELVIS benchtop workstation

LabVIEW 8.6

VIs from the project “Data Acquisition Using NI-DAQmx”
References
Student’s Portion
Introduction
The students will build the electrocardiogram (ECG) amplifier based on the
provided schematics diagram. They will develop a VI that can detect the R
wave in the ECG signal and convert the R-R interval into heart rate. The ECG
amplifier will be based on the circuits developed in the previous projects of
instrumentation amplifier and filters. The students will modify the data
acquisition VIs developed in the previous project titled “Data Acquisition
Using NI-DAQmx VIs” to collect ECG and measure heart rate.
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Objectives



ECG amplifier
Data acquisition using LabVIEW
Data analysis using LabVIEW
Theory
The basic ECG amplifier consists of two components. The first component
is the instrumentation amplifier with typical gain of 1000 (60dB). The
second component is the band-pass filter. The low cutoff frequency is
around 0.5Hz to minimize the baseline shift. The high cutoff frequency is
around 100Hz for antialiasing purpose.
Lab Procedure
1. Keep ELVIS workstation power off.
2. Verify that the instrument amplified and bandpass filter built in the
previous lab sessions are working properly.
3. Change the resistors R4 and R5 from 200kΩ to 10kΩ.
4. connect the output of the instrument amplifier to the input of the band
pass filter
5. Connect BANANA A on the prototyping board to the positive input of
instrumentation amplifier (Pin 3 of LF353)
6. Connect BANANA B on the prototyping board to the negative input of
instrumentation amplifier (Pin 5 of LF353)
7. Turn on the ELVIS workstation.
8. Place two ECG electrodes on the wrists of both arms and connect the
electrodes to the connectors (left arm to BANANA A & right arm to
BANANA B) of the ELEVIS station. On the breadboard, BANANA A
should be connected to the positive input of the amplifier and
BANANA B should be connected to the negative input of the
amplifier.
9. Place the third electrode on the abdomen and connect it to the
connector (BANANA C) of the ELVIS workstation. BANANA C
should connect to the GND on the prototype board.
10. Launch LabVIEW and ELVIS.
11. Use ELVIS scope to check the ECG signal.
12. Using finite data acquisition VI to record ECG signals
13. Modify the continuous data acquisition VI measure the heart rate. The
sub VI for the measurement of heart rate should be finished before the
lab. Students are encouraged to develop their own algorithms.
Lab Report
The lab report also includes the bioinstrumentation project.
This port of lab report should contain the following:
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1. The experiment objective
2. The experiment procedure and theory including description of heart
rate measurement algorithm.
3. Experiment results, which include ECG recordings
4. Discussion
5. You must submit all VIs for the heart rate measurement with the
documentation.
Lab report due 12/11/2009
Extra credit
You can develop an ECG analysis module to analyze the collected ECG
signals. The best approach is to do a search for researches in ECG signal
analysis and implement the method in your project.
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Appendix:
Schematics for ECG amplifier
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Prototype layout
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