Correct data format to write to a spesific destination via API

I am writing a nd trying to combine a simple program which reads physiological data from shimmer(ECG-type data). My problem currently is, that I have no idea what command to use to write the data from the code to the spesific path. Sorry For the lengthy code pieces. The Problems is on the row

 %% definitions

    shimmer = ShimmerHandleClass(comPort);
    SensorMacros = SetEnabledSensorsMacrosClass;                               % assign user friendly macros for setenabledsensors

    fs = 512;                                                                  % sample rate in [Hz]
    firsttime = true;

    % Note: these constants are only relevant to this examplescript and are not used
    % by the ShimmerHandle Class
    NO_SAMPLES_IN_PLOT = 5000;                                                 % Number of samples in the plot 
    DELAY_PERIOD = 0.2;                                                        % Delay (in seconds) between data read operations
    numSamples = 0;

    %% settings

    % filtering settings
    fm = 50;                                                                   % mains frequency [Hz]
    fchp = 0.5;                                                                % corner frequency highpassfilter [Hz]; Shimmer recommends 0.5Hz for monitoring applications, 0.05Hz for diagnostic settings
    nPoles = 4;                                                                % number of poles (HPF, LPF)
    pbRipple = 0.5;                                                            % pass band ripple (%)
    
    HPF = true;                                                                % enable (true) or disable (false) highpass filter
    LPF = true;                                                                % enable (true) or disable (false) lowpass filter
    BSF = true;                                                                % enable (true) or disable (false) bandstop filter
    
    % highpass filters for ExG channels
    if (HPF)
        hpfexg1ch1 = FilterClass(FilterClass.HPF,fs,fchp,nPoles,pbRipple);
        hpfexg1ch2 = FilterClass(FilterClass.HPF,fs,fchp,nPoles,pbRipple);
        hpfexg2ch1 = FilterClass(FilterClass.HPF,fs,fchp,nPoles,pbRipple);
        hpfexg2ch2 = FilterClass(FilterClass.HPF,fs,fchp,nPoles,pbRipple);
    end
    % lowpass filters for ExG channels
    if (LPF)
        lpfexg1ch1 = FilterClass(FilterClass.LPF,fs,fs/2-1,nPoles,pbRipple);
        lpfexg1ch2 = FilterClass(FilterClass.LPF,fs,fs/2-1,nPoles,pbRipple);
        lpfexg2ch1 = FilterClass(FilterClass.LPF,fs,fs/2-1,nPoles,pbRipple);
        lpfexg2ch2 = FilterClass(FilterClass.LPF,fs,fs/2-1,nPoles,pbRipple);
    end
    % bandstop filters for ExG channels;
    % cornerfrequencies at +1Hz and -1Hz from mains frequency
    if (BSF)
        bsfexg1ch1 = FilterClass(FilterClass.LPF,fs,[fm-1,fm+1],nPoles,pbRipple);
        bsfexg1ch2 = FilterClass(FilterClass.LPF,fs,[fm-1,fm+1],nPoles,pbRipple);
        bsfexg2ch1 = FilterClass(FilterClass.LPF,fs,[fm-1,fm+1],nPoles,pbRipple);
        bsfexg2ch2 = FilterClass(FilterClass.LPF,fs,[fm-1,fm+1],nPoles,pbRipple);
    end
    

    
    %%
    if (shimmer.connect)
        shimmer.setsamplingrate(fs);                                           % Select sampling rate
        shimmer.setinternalboard('ECG');                                       % Select internal expansion board; select 'ECG' to enable both SENSOR_EXG1 and SENSOR_EXG2 
        shimmer.disableallsensors;                                             % Disable other sensors
        shimmer.setenabledsensors(SensorMacros.ECG,1)                          % Enable SENSOR_EXG1 and SENSOR_EXG2
       
        if (shimmer.start)                                                     % TRUE if the shimmer starts streaming 

            plotData = [];                                               
            timeStamp = [];
            filteredplotData = [];

            h.figure1=figure('Name','Shimmer ECG signals');                    % Create a handle to figure for plotting data from shimmer
            set(h.figure1, 'Position', [100, 500, 800, 400]);
            h.figure2=figure('Name','Shimmer ECG signals');                    % Create a handle to figure for plotting data from shimmer
            set(h.figure2, 'Position', [950, 500, 800, 400]);

            elapsedTime = 0;                                                   % Reset to 0    
            tic;                                                               % Start timer

            while (elapsedTime < captureDuration)       

                pause(DELAY_PERIOD);                                           % Pause for this period of time on each iteration to allow data to arrive in the buffer

                [newData,signalNameArray,signalFormatArray,signalUnitArray] = shimmer.getdata('c');   % Read the latest data from shimmer data buffer, signalFormatArray defines the format of the data and signalUnitArray the unit

                
                if (firsttime==true && isempty(newData)~=1)
                    firsttime = writeHeadersToFile(fileName,signalNameArray,signalFormatArray,signalUnitArray);
                end

                if ~isempty(newData)                                           % TRUE if new data has arrived
                    
                    chIndex(1) = find(ismember(signalNameArray, 'ECG LL-RA'));
                    chIndex(2) = find(ismember(signalNameArray, 'ECG LA-RA'));
                    chIndex(3) = find(ismember(signalNameArray, 'ECG Vx-RL'));
                    chIndex(4) = find(ismember(signalNameArray, 'ECG RESP'));
                    
                    ECGData = newData(:,chIndex);
                    ECGDataFiltered = ECGData;
                    % filter the data
                    if HPF % filter newData with highpassfilter to remove DC-offset
                        ECGDataFiltered(:,1) = hpfexg1ch1.filterData(ECGDataFiltered(:,1));
                        ECGDataFiltered(:,2) = hpfexg1ch2.filterData(ECGDataFiltered(:,2));
                        ECGDataFiltered(:,3) = hpfexg2ch1.filterData(ECGDataFiltered(:,3));
                        ECGDataFiltered(:,4) = hpfexg2ch2.filterData(ECGDataFiltered(:,4));
                    end
                    
                    if BSF % filter highpassfiltered data with bandstopfilter to suppress mains interference
                        ECGDataFiltered(:,1) = bsfexg1ch1.filterData(ECGDataFiltered(:,1));
                        ECGDataFiltered(:,2) = bsfexg1ch2.filterData(ECGDataFiltered(:,2));
                        ECGDataFiltered(:,3) = bsfexg2ch1.filterData(ECGDataFiltered(:,3));
                        ECGDataFiltered(:,4) = bsfexg2ch2.filterData(ECGDataFiltered(:,4));
                    end
                    
                    if LPF % filter bandstopfiltered data with lowpassfilter to avoid aliasing
                        ECGDataFiltered(:,1) = lpfexg1ch1.filterData(ECGDataFiltered(:,1));
                        ECGDataFiltered(:,2) = lpfexg1ch2.filterData(ECGDataFiltered(:,2));
                        ECGDataFiltered(:,3) = lpfexg2ch1.filterData(ECGDataFiltered(:,3));
                        ECGDataFiltered(:,4) = lpfexg2ch2.filterData(ECGDataFiltered(:,4));
                    end
                    
                    dlmwrite(fileName, newData, '-append', 'delimiter', '\t','precision',16); % Append the new data to the file in a tab delimited format
                    plotData = [plotData; ECGData];                            % Update the plotData buffer with the new ECG data
                    filteredplotData = [filteredplotData; ECGDataFiltered];    % Update the filteredplotData buffer with the new filtered ECG data
                    numPlotSamples = size(plotData,1);
                    numSamples = numSamples + size(newData,1);
                    timeStampNew = newData(:,1);                                   % get timestamps
                    timeStamp = [timeStamp; timeStampNew];
                    if numSamples > NO_SAMPLES_IN_PLOT
                        plotData = plotData(numPlotSamples-NO_SAMPLES_IN_PLOT+1:end,:);
                        filteredplotData = filteredplotData(numPlotSamples-NO_SAMPLES_IN_PLOT+1:end,:);
                    end
                    sampleNumber = max(numSamples-NO_SAMPLES_IN_PLOT+1,1):numSamples;
                    

Problem is found here. I am trying to forward the data with writing functions. But since I don't exactly know the correct command or syntax, I have no clue what to use?. The data I want to write forward is if i understood right located in newData. Below are the commands to open the local connection and closing it. I have tried dlwrite and fwrite already, though the syntax seemed not to work..

u=udp('127.0.0.1',8089);
                    fopen(u);
                    dlwrite(newData, u, 'delimiter', ',');
                    fclose(u);
                    % u=udp('127.0.0.1',8089);
                   %fopen(u);
                   % fwrite(u,newData);
                    %fclose(u);
                  

The data I want to write outside to the spesific U-destination is outputted as seperate xml file currently:

                    set(0,'CurrentFigure',h.figure1);   
                    subplot(2,2,1);                                        % Create subplot
                    signalIndex = chIndex(1);
                    plot(sampleNumber,plotData(:,1));                      % Plot the ecg for channel 1 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);

                    subplot(2,2,2);                                        % Create subplot
                    signalIndex = chIndex(2);
                    plot(sampleNumber,plotData(:,2));                      % Plot the ecg for channel 2 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);

                    subplot(2,2,3);                                        % Create subplot
                    signalIndex = chIndex(1);
                    plot(sampleNumber,filteredplotData(:,1));              % Plot the filtered ecg for channel 1 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' 'filtered' ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);

                    subplot(2,2,4);                                        % Create subplot
                    signalIndex = chIndex(2);
                    plot(sampleNumber,filteredplotData(:,2));              % Plot the filtered ecg for channel 2 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' 'filtered' ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);
                    
                    
                    set(0,'CurrentFigure',h.figure2);   
                    subplot(2,2,1);                                        % Create subplot
                    signalIndex = chIndex(3);
                    plot(sampleNumber,plotData(:,3));                      % Plot the ecg for channel 1 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);

                    subplot(2,2,2);                                        % Create subplot
                    signalIndex = chIndex(4);
                    plot(sampleNumber,plotData(:,4));                      % Plot the ecg for channel 2 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);

                    subplot(2,2,3);                                        % Create subplot
                    signalIndex = chIndex(3);
                    plot(sampleNumber,filteredplotData(:,3));              % Plot the filtered ecg for channel 1 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' 'filtered' ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);

                    subplot(2,2,4);                                        % Create subplot
                    signalIndex = chIndex(4);
                    plot(sampleNumber,filteredplotData(:,4));              % Plot the filtered ecg for channel 2 of SENSOR_EXG1
                    legendName1=[signalFormatArray{signalIndex} ' ' 'filtered' ' ' signalNameArray{signalIndex} ' (' signalUnitArray{signalIndex} ')'];  
                    legend(legendName1);                                   % Add legend to plot
                    xlim([sampleNumber(1) sampleNumber(end)]);
            
                end

                elapsedTime = elapsedTime + toc;                           % Update elapsedTime with the time that elapsed since starting the timer
                tic;                                                       % Start timer           

            end  
          
            elapsedTime = elapsedTime + toc;                               % Update elapsedTime with the time that elapsed since starting the timer
            fprintf('The percentage of received packets: %d \n',shimmer.getpercentageofpacketsreceived(timeStamp)); % Detect loss packets
            shimmer.stop;                                                  % Stop data streaming                                                    

        end 

    end
    

    shimmer.disconnect;
    
    
    
    clear shimmer;
    
  

Answer 1

[Anmol Dhiman]

Hi Iiro Koskialho,

I assume the problem is with sending the data over udp.

These are my suggestions

1) Use udpport instead of udp.

2) First extract data for a fixed size and try to keep it of a same type. Pass this data over the udp.

Regards,

Anmol Dhiman