Reading a Voltage in Arduino using Matlab.

Hi,

I am trying to read a voltage in Arduino with help from a Potentiometer or a piezo. Until now I'am having some trouble to make the Program run into Matlab. I already used the software from Arduino so the Controller is not the problem since the Serial monitor is reading the values. But I can't actually bring these values to a Graph.

Can somebody help me?

Thank you.

The Code:

clear all
clc

%clear the screen
delete(instrfind({'Port'},{'/dev/tty.usbmodem641'}));
%create the object(serie)
s = serial('/dev/tty.usbmodem641','BaudRate',9600,'Terminator','CR/LF');
warning('off','MATLAB:serial:fscanf:unsuccessfulRead');
%abrir puerto
fopen(s);

% parameters.
tmax = 10; % tiempo de captura en s
rate = 33; % resultado experimental (comprobar)

% figure
f = figure('Name','Captura');
a = axes('XLim',[0 tmax],'YLim',[0 5.1]);
l1 = line(nan,nan,'Color','r','LineWidth',2);
l2 = line(nan,nan,'Color','b','LineWidth',2);

xlabel('Tiempo (s)')
ylabel('Voltaje (V)')
title('Captura de voltaje en tiempo real con Arduino')
grid on
hold on

% initialize 
v1 = zeros(1,tmax*rate);
v2 = zeros(1,tmax*rate);
i = 1;
t = 0;

tic
while t<tmax
    t = toc;
    % read the port
    a = fscanf(s,'%f,%f');
    v1(i)=a(1)*5/1024;
    v2(i)=a(2)*5/1024;
    % dibujar en la figura
    x = linspace(0,i/rate,i);
    set(l1,'YData',v1(1:i),'XData',x);
    set(l2,'YData',v2(1:i),'XData',x);
    drawnow
    % seguir
    i = i+1;

end
% results
clc;
fprintf('%g s de captura a %g cap/s \n',t,i/t);

%%clean the screen.
fclose(s);
delete(s);
clear s;

[Ryan G]

Are you able to verify the parameters in your workspace?

[John Petersen]

Yes, put a breakpoint at v1(i) and verify that 'a' is correct.