I have been trying to get realtime ecg data from arduino using matlab.
I am able to visualise the real time data using this code.
Here the issue is I cannot get the filtered output at the same time as I am not aware of the fs.
Would like to know how we can process the signal realtime and plot the output.
I am attaching the result I am getting with this code (0 to 200)
The output is taken from arduino pin A0
clear
clc
close all
%get some user settings
%ledPin = 'D13'; %For blinking the led we should access this pin
%deltaT_blink = 0.5;
port = 'COM5';
board = 'Uno';
a = arduino(port,board); % we are creating an arduino object with this specific board and this specific port
%write a small for loop that flashes the LED on and off
% for k = 1:20
% %turn the arduino LED on
% a.writeDigitalPin(ledPin,1);
% pause(deltaT_blink*5);
% %turn the arduino LED off
% a.writeDigitalPin(ledPin,0);
% pause(deltaT_blink*2);
%
% end
init_time = 1;
x =0;
s=0;
f = 0;
tic
while(init_time
To achieve real-time processing and visualization of the filtered data, you need to modify the code as follows:
Move the filter coefficient calculation ([b1, a1] = butter(4, fc/(fs/2), 'bandpass');) outside the while loop. This ensures that the coefficients are only calculated once and not repeatedly in each iteration.
Create a buffer array (ecg_buffer) to store a window of the ECG data.
Update the buffer with the new ECG samples in each iteration.
Apply the filter to the buffer (ecg_filtered = filter(b1, a1, ecg_buffer);).
Plot the filtered data (subplot(2,1,2); plot(ecg_filtered);).
Your question does not contain all the necessary information to answer. An Arduino without an ECG amplifier cannot measure a millivolt signal. And the ECG amplifier has built-in filters.
What exactly is your problem?
I don't kmow what the smapling rate is .
What should I take.
Yes there is an ECG amplifier,from that only the output is connected to A0
But I am having trouble in designing the filter as I dont know what the 'fs' is
Your graph has 200 counts and 18 pulse periods. Assuming a pulse period of about 1 second, the most likely sampling rate is 10 samples per second.
A sampling rate of 10sps is clearly not enough for any kind of filtering ECG. At a minimum, it is necessary to supplement the sample with interpolated values to bring it up to 100-200sps.
I agree with Vladimir, you should increase the fs to at least 150-200 Hz.
Okay so I will have to upsample to 200 Hz or so and then design a filter?
There are many papers on this topic. For example:
https://www.sciencedirect.com/science/article/pii/S2352711020303526
https://dergipark.org.tr/en/download/article-file/1802588
https://www.diva-portal.org/smash/get/diva2:1601275/FULLTEXT01.pdf
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