CODEWITHSUNDEEP
matlabarduinoserial-portpyserialreal-time-data
noureddine-as
noureddine-as

Reputation: 523

Non Real Time Serial Data Plotter

I'm working on a motion sensor project, and I would like to acquire acceleration data from a sensor (MPU6050) attached to Arduino. So I get the 3 values of acceleration ax, ay and az and I send them in the USB serial link.

Now I can get the ax, ay, and az values and plot them correctly and all is working good.

THE PROBLEM: is that it's not real-time, ie. when I vibrate the sensor the values don't change simultaneousely like the instant serial plotter of Arduino which I didn't use because I want to analyse these data later in MATLAB (to do pattern recognition tasks so I can distinguish movements).

This is my code, I need to know what part consumes that time and what can I do to overcome this problem?

NOTE: I tried to use also pySerial to acquire data and Matplotlib but I had the same problem, it's not simultaneous.

%%real time data plot from a serial port
% Original script written by Moidu thavot.

%%Clear all variables
clc;
clear all;
close all;

if isempty(instrfind) == 0
    fclose(instrfind); % Close com ports
    delete(instrfind); % Clear com ports
end

%%Variables (Edit yourself)

SerialPort='com6'; %serial port
TimeInterval=0;%time interval between each input.
loop=inf;%count values
yMIN = -100;
yMAX = 100;
xWIDTH = 200;
%%Set up the serial port object
s = serial(SerialPort, 'BaudRate', 115200); % setup comport
fopen(s);

time = now;
y1 = 0;
y2 = 0;
y3 = 0;
%% Set up the figure
figureHandle = figure('NumberTitle','off',...
    'Name','Acceleration Plots',...
    'Color',[0 0 0],'Visible','off');

% Set axes
axesHandle = axes('Parent',figureHandle,...
    'YGrid','on',...
    'YColor',[0.9725 0.9725 0.9725],...
    'XGrid','on',...
    'XColor',[0.9725 0.9725 0.9725],...
    'Color',[0 0 0]);

hold on;

plotHandle1 = plot(axesHandle,time,y1,'LineWidth',1,'Color',[1 0 0]);
plotHandle2 = plot(axesHandle,time,y2,'LineWidth',1,'Color',[0 1 0]);
plotHandle3 = plot(axesHandle,time,y3,'LineWidth',1,'Color',[0 0 1]);

%xlim(axesHandle,[min(time) max(time+0.001)]);
%ylim([yMIN yMAX]);

% Create xlabel
xlabel('Time','FontWeight','bold','FontSize',14,'Color',[1 1 0]);

% Create ylabel
ylabel('Acceleration Values','FontWeight','bold','FontSize',14,'Color',[1 1 0]);

% Create title
title('Real Time Data','FontSize',15,'Color',[1 1 0]);

%% Initializing variables

y1(1)=0;
y2(1)=0;
y3(1)=0;
time(1)=0;
count = 2;
while ~isequal(count,loop)

    u = fscanf(s, '%f %f %f');
    y1(count) = u(1);
    y2(count) = u(2);
    y3(count) = u(3);

    time(count) = count;

    xlim([max(time-xWIDTH) max(time)]);

    set(plotHandle1,'YData',y1,'XData',time);
    set(plotHandle2,'YData',y2,'XData',time);
    set(plotHandle3,'YData',y3,'XData',time);
    set(figureHandle,'Visible','on');
    datetick('x','mm/DD HH:MM');

    pause(TimeInterval);
    count = count +1;
end

%% Clean up the serial port
fclose(s);
delete(s);
clear s;

Upvotes: 1

Views: 632

Answers (1)

Laleh
Laleh

Reputation: 508

1- Get rid of the pause in your while loop. Instead, take a look at what you are reading from the serial port if data is available go ahead with the processing and showing, if not repeat the loop.

2- Use 'drawnow' with 'limitrate' after you set the plots

3- check the baudrate, In MATLAB side you can still increase it. I don't know about the arduino side

Upvotes: 1

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