ECG Heart Rate Monitor
November 2021 - December 2021
Status: Completed
This was developed as a class project for Circuits and Signals to enhance knowledge on instrumental and operational amplifiers. It contains two stages of analog filtering and then digital filtering. It displayed the heart rhythms and heart rate in MATLAB using a National Instruments DAQ.
Purpose of the project
The purpose of this project was to learn more about the properties and usages of instrumental and operation amplifiers. Throughout this project, I had to choose components that fit specific needs as well as choose operation amplifier configurations to help isolate the very faint heart signal.
Outcome
After completion of this project, I now have proficiency in:
Operational Amplifiers
Frequency Domain Analysis
Oscilloscope, Digital Multimeter, and Function Generators
Circuit Debugging Skills
This project resulted in extremely clear and easy to read heart beat signals. The specific frequency of the heart beats were isolated, and therefore, the signal integrity was excellent which is needed for an accurate medical assessment.
Steps
Set Up Instrumental Amplifier
The first step of the project was to use an instrumental amplifier. The purpose of this was to make the extremely faint heart signal easier to manipulate. Although more amplification was needed to achieve a 3Vpp range, this allowed me to get a better idea of the frequency content of the heart signal in order to isolate it properly in the subsequent stages.
Add Filtering Stages
Since the heart signal operates at a few Hertz, isolating it was quite difficult. First, a high pass filter was added to remove the lower frequencies. Then, a low pass filter was added in order to remove the high frequency noise generated by the measurement. Once the signal was devoid of all unwanted noise, the pulse signal was ready to read using a DAQ.
Heart Rate DAQ Reading
Lastly, the output from the amplifier was read by a Data Acquisition (DAQ) unit. The sampling rate was chosen to avoid aliasing. After the acquisition, digital filters were added by using a Parks-McClellan filter with a Notch filter in order to isolate and amplify the heart signal even further.