Real time acquisition using drawnow
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I tried to read data from AD8232 ECG Module using HC-05 and plot the signal in real time. But when I try drawnow it give a sample rate of 40-60 Hz and with drawnow limitrate it gives some random data and the final results its nothing like the ecg from arduino ide even if i have 500 Hz sample rate. I then tried to pause for 0.001 s and the sample rate is good 160 Hz, the signal is ok, but its with 1 minute delay and its not stopping even when i press ctr+c.
The code implemented is below:
b = instrfind('Type', 'bluetooth', 'Name', 'Bluetooth-HC-05:1', 'Tag', '');
if isempty(b)
b = Bluetooth('HC-05', 1);
else
fclose(b);
b = b(1);
end
fopen(b);
figure
h = animatedline;
ax = gca;
ax.YGrid = 'on';
i=1;
x = zeros();
stop = false;
startTime = datetime('now');
while ~stop
x(1,i) = str2double(fscanf(b));
t = time2num((datetime('now') - startTime),'seconds');
if isnan(x(1,i))
x(1,i) = 0;
end
addpoints(h,t,x(1,i))
ax.XLim = [t-3 t];
i = i+1;
drawnow limitrate
pause(0.001)
end
Please is there a function beside pause to slow down the drawnow limitrate without delaying the acquisition?
Below is the acquisition with pause and without it.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/621333/image.jpeg)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/621338/image.jpeg)
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