How to do TKEO based Peak Detector in ECG In Simulink Realtime?

I have been trying to do ECG peak detection using TKEO in matlab and has done the same in matlab and has got results

Heres the code for it

% Passband frequency range in Hz

[b, a] = butter(4, fc/(fs/2), 'bandpass');

ecg_filtered = filter(b, a, ecg);

% Apply TKEO to enhance R-peaks

tkeo = ecg_filtered(2:end-1).^2 - ecg_filtered(1:end-2).*ecg_filtered(3:end);

% Apply moving average filter to smooth the TKEO signal

win_size = round(fs*0.15); % Window size in samples (0.15 seconds)

tkeo_smooth = movmean(tkeo, win_size);

% Find R-peak locations

[r_peaks_tkeo, r_locs_tkeo] = findpeaks(tkeo_smooth, 'MinPeakDistance', 50,'MinPeakHeight',mean(tkeo_smooth)); % 0.2 seconds between R-peaks

r_locs_tkeo_updated = r_locs_tkeo+3;

figure;

plot(t, ecg_filtered);

xlim([0 10])

title('Filtered ECG')

xlabel('Time(Sec)')

ylabel('Amplitude')

But Now I would like to do the same realtime using simulink and arduino.

I have done the filtering using Butterworth filter part in Simulink using Digital filter design block.

But I dont know how to implement the TKEO Block so that I would get R peaks.

Kindly Help Me Out

Thank You in Advance

Answer 1

[Divit]

Hi Krishnapriya,

I understand that you are looking for assistance in translating your MATLAB code for ECG peak detection using TKEO into a real-time Simulink model that can be used with an Arduino for continuous ECG data processing.

To implement the TKEO algorithm, you can create a custom “MATLAB Function block” Here’s a step-by-step breakdown of how to implement the TKEO algorithm in Simulink:

• Create a MATLAB Function block.
• In the MATLAB Function block, define the algorithm following your MATLAB code. Here's an example implementation of the TKEO algorithm in Simulink's MATLAB Function block:

function tkeo_output = myTKEO(ecg_filtered)
    % Apply TKEO to enhance R-peaks
    tkeo = ecg_filtered(2:end-1).^2 - ecg_filtered(1:end-2) .* ecg_filtered(3:end);
    % Return the TKEO signal
    tkeo_output = tkeo;
end

• Connect the input (filtered ECG signal) to the MATLAB Function block.
• Connect the output of the MATLAB Function block to the subsequent blocks in your model.

R-Peak Detection:

To detect R-peaks in the TKEO signal, you can use a “Switch block” as a threshold or a custom “MATLAB Function block”. The key idea is to set a threshold and detect peaks in the TKEO signal above that threshold.

To know more you can refer to the following documentation links:

• MATLAB Function Block: https://www.mathworks.com/help/simulink/ug/what-is-a-matlab-function-block.html
• Switch Block: https://www.mathworks.com/help/simulink/slref/switch.html

I hope this helps!