Matlab real time ploting multiple data from serial port

Question

My application reads data from sensors trough an ARDUINO UNO platform and then trough serial port I managed to read all the data that I need in MATLAB. so now I have 3 datas that I want to plot (data, data2, data3) in real time ON THE SAME GRAPHIC.

I also managed to plot one data at a time with some code I found on mathworks and modified it a bit, which does not suit my project.

Here is the matlab code that I'm using to plot one of the data:

clear
clc

%User Defined Properties 
serialPort = 'COM7';           % define COM port #
baudeRate = 115200;
plotTitle = 'Serial Data Log';  % plot title
xLabel = 'Elapsed Time (s)';    % x-axis label
yLabel = 'Data';                % y-axis label
plotGrid = 'on';                % 'off' to turn off grid
min = -200;                     % set y-min
max = 200;                      % set y-max
scrollWidth = 10;               % display period in plot, plot entire data log if <= 0
delay = .01;                    % make sure sample faster than resolution

%Define Function Variables
time = 0;
data = 0;
data2 = 0;
data3 = 0;
count = 0;

%Set up Plot
plotGraph = plot(time,data,time,data2,time,data3);

title(plotTitle,'FontSize',25);
xlabel(xLabel,'FontSize',15);
ylabel(yLabel,'FontSize',15);
axis([0 10 min max]);
grid(plotGrid);

%Open Serial COM Port
s = serial(serialPort, 'BaudRate',baudeRate)
disp('Close Plot to End Session');
fopen(s);

tic

while ishandle(plotGraph) %Loop when Plot is Active

    dat = fscanf(s,'%f'); %Read Data from Serial as Float

    if(~isempty(dat) && isfloat(dat)) %Make sure Data Type is Correct        
        count = count + 1;    
        time(count) = toc;    %Extract Elapsed Time
        data(count) = dat(1); %Extract 1st Data Element  
        data2(count) = dat(2);
        data3(count) = dat(3);

        data(count);
        data2(count);
        data3(count);

        %Set Axis according to Scroll Width
        if(scrollWidth > 0)
        set(plotGraph,'XData',time(time > time(count)-scrollWidth),'YData',data3(time > time(count)-scrollWidth));
        %plot(time(time > time(count)-scrollWidth),data3(time > time(count)-scrollWidth));
        axis([time(count)-scrollWidth time(count) min max]);
        %set(plotGraph,'XData',time(time > time(count)-scrollWidth),'YData',data3(time > time(count)-scrollWidth));
        %axis([time(count)-scrollWidth time(count) min max]);
        else
        set(plotGraph,'XData',time,'YData',data);
        axis([0 time(count) min max]);
        end

        %Allow MATLAB to Update Plot
        pause(delay);
    end
end

%Close Serial COM Port and Delete useless Variables
fclose(s);
clear count dat delay max min baudRate plotGraph plotGrid plotTitle s ...
        scrollWidth serialPort xLabel yLabel;


disp('Session Terminated...');

I need to plot all the 3 datas (data, data2, data3) on the graphic with different colors. Please help me out here.

Try hold on first. Also, take a look at mathworks.com/help/matlab/ref/lineseriesproperties.html and focus on X/Y/Z/Data. — Yvon
– Yvon, Commented Jul 24, 2014 at 7:08

Tyler · Accepted Answer · 2015-06-14 14:55:13Z

I actually used the code from the same source you are for one of my projects. If you still need assistance, here is my modified version of the code I used to plot three data lines from an accelerometer. It plots beautifully. However, because of the time it takes to do fscanf(), you can't obtain and plot a signal in real time faster than every 50ms or so without aliasing.

clear
clc

%User Defined Properties 
serialPort = 'COM7';            % define COM port #
plotTitle = 'Serial Data Log';  % plot title
xLabel = 'Elapsed Time (s)';    % x-axis label
yLabel = 'Acceleration';                % y-axis label
plotGrid = 'on';                % 'off' to turn off grid
min = -1.5;                     % set y-min
max = 2.5;                      % set y-max
scrollWidth = 10;               % display period in plot, plot entire data log if <= 0
delay = .0000001;                    % make sure sample faster than resolution

%Define Function Variables
time = 0;
data = zeros(3,1);
count = 0;

%Set up Plot
plotGraph = plot(time,data(1,:),'-r',...
            'LineWidth',2,...
            'MarkerFaceColor','w',...
            'MarkerSize',2);
hold on
plotGraph1 = plot(time,data(2,:),'-m',...
            'LineWidth',1,...
            'MarkerFaceColor','w',...
            'MarkerSize',2);
hold on
plotGraph2 = plot(time,data(3,:),'-b',...
            'LineWidth',1,...
            'MarkerFaceColor','w',...
            'MarkerSize',2);

title(plotTitle,'FontSize',25);
xlabel(xLabel,'FontSize',15);
ylabel(yLabel,'FontSize',15);
axis([0 10 min max]);
grid(plotGrid);

%Open Serial COM Port
s = serial(serialPort, 'BaudRate', 115200)
disp('Close Plot to End Session');
fopen(s);

tic

while ishandle(plotGraph) && ishandle(plotGraph2) && ishandle(plotGraph1)  %Loop when Plot is Active

dat = fscanf(s,'%f'); %Read Data from Serial as Float

if(~isempty(dat) && isfloat(dat)) %Make sure Data Type is Correct        
    count = count + 1;    
    time(count) = toc;    %Extract Elapsed Time in seconds
    data(:,count) = dat(:,1); %Extract 1st Data Element         

    %Set Axis according to Scroll Width
    if(scrollWidth > 0)
    set(plotGraph,'XData',time(time > time(count)-scrollWidth),...
        'YData', data(3,time > time(count)-scrollWidth));
    set(plotGraph1,'XData',time(time > time(count)-scrollWidth),...
        'YData', data(2,time > time(count)-scrollWidth));
    set(plotGraph2,'XData',time(time > time(count)-scrollWidth),...
        'YData', data(1,time > time(count)-scrollWidth));

    axis([time(count)-scrollWidth time(count) min max]);
    else
    set(plotGraph,'XData',time,'YData',data(3,:));
    set(plotGraph1,'XData',time,'YData',data(2,:));
    set(plotGraph2,'XData',time,'YData',data(1,:));

    axis([0 time(count) min max]);
    end

    %Allow MATLAB to Update Plot
    pause(delay);
end
end

%Close Serial COM Port and Delete useless Variables
fclose(s);

clear count dat delay max min plotGraph plotGraph1 plotGraph2 plotGrid...
    plotTitle s scrollWidth serialPort xLabel yLabel;

disp('Session Terminated');

prompt = 'Export Data? [Y/N]: ';
str = input(prompt,'s');
if str == 'Y' || strcmp(str, ' Y') || str == 'y' || strcmp(str, ' y')
    %export data
    csvwrite('accelData.txt',data);
    type accelData.txt;
else
end

clear str prompt;

what is the format of input in your code?the three axis value of the accelerometer.

LVitya · Accepted Answer · 2014-10-14 10:10:16Z

0

Use line function to create one more line on the same plot.
From Help->MatLab->Graphics->Handle Graphics Objects->High-Level Versus Low-Level

If you call the line function a second time, MATLAB draws the second line in the current axes without erasing the first line.

answered Oct 14, 2014 at 10:10

LVitya

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Comments

kay_tsao · Accepted Answer · 2015-05-01 02:50:33Z

0

Simply use the following:

plotGraph = plot(time(time > time(count) - scrollWidth), data(time > time(count) - scrollWidth),...
time(time > time(count) - scrollWidth), data2(time > time(count) - scrollWidth),...
time(time > time(count) - scrollWidth),data3(time > time(count) - scrollWidth));
grid on;    
axis([time(count) - scrollWidth time(count) min max]);

answered May 1, 2015 at 2:50

kay_tsao

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