Plotting live data from Arduino in Matlab

Hi all,

Apologies if this has already been covered - I couldn't find any information and I am new to Matlab and Arduino! I want to plot water level data obtained from my Arduino Uno plugged into a Milone eTape water depth sensor. I've got the code running successfully in a freeware software called SerialPlot but I want to plot this data into Matlab. The code I am using on the Arduino is below. How do I go about plotting the data in real time on Matlab?

Thanks so much in advance!

Dan

        // the value of the 'other' resistor
    #define SERIESRESISTOR 560     
    // What pin to connect the sensor to
    #define SENSORPIN A0

    void setup(void) {
      Serial.begin(38400);
    }

    void loop(void) {
      float Reading;
      float level;
      float Reading2;
      float mapped;

     Reading = analogRead(SENSORPIN);

   //  Serial.print("Analog reading ");
   //  Serial.println(Reading);

     //convert the value to resistance
     Reading2 = (1023 / Reading)  - 1;
     Reading2 = SERIESRESISTOR / Reading2;
     //Serial.print("Sensor resistance ");
     //Serial.println(Reading2);

      mapped = map(Reading2, 658.89, 1695.43 , 150, 0);
   // map (Reading2, Highest Depth Resistance, Lowest Depth Resistance, Depth Difference, Lowest Depth)
  //  Serial.print("");
    Serial.println(mapped);

      delay(10);
    }

Answer 1

[Madhu Govindarajan]

have you tried animatedline function in MATLAB? I doubt you can do 100% real-time with Arduino but I think this is what you are looking for.

http://www.mathworks.com/help/matlab/ref/animatedline.html

[Madhu Govindarajan]

I meant try using this for the plotter and using MATLAB Support package to bring in the data to MATLAB from Arduino - www.mathworks.com/hardware-support/arduino-matlab.html

[Daniel Green]

Hi Madhu,

Thanks for your reply. I've installed the MATLAB support package to bring data from the Arduino into MATLAB but was wondering what I would need to input into the MATLAB command window to get the live data to show in a graphical format with 'time (s)' along the x axis and 'Water depth (mm) ' from the Arduino on the y axis. I'm new to MATLAB so not familiar with what I would need to do to create a graph showing this data.

I believe I need to type something similar to this in the MATLAB command prompt although this doesn't export the series values obtained for Water Depth (mm):

%%Create serial object for Arduino
s = serial('COM9');
%%Connect the serial port to Arduino
s.InputBufferSize = 1; % read only one byte every time
try
    fopen(s);
catch err
    fclose(instrfind);
    error('Make sure you select the correct COM Port where the Arduino is connected.');
end
%%Create a figure window to monitor the live data
Tmax = 1000; % Total time for data collection (s)
figure,
grid on,
xlabel ('Time (s)'), ylabel('Water depth (mm)'),
axis([0 Tmax+1 0 200]),
%%Read and plot the data from Arduino
Ts = 1; % Sampling time (s)
i = 0;
data = 0;
t = 0;
tic % Start timer
while toc <= Tmax
    i = i + 1;
    %%Read buffer data
    data(i) = fread(s);
    %%Read time stamp
    % If reading faster than sampling rate, force sampling time.
    % If reading slower than sampling rate, nothing can be done. Consider
    % decreasing the set sampling time Ts
    t(i) = toc;
    if i > 1
        T = toc - t(i-1);
        while T < Ts
            T = toc - t(i-1);
        end
    end
    t(i) = toc;
    %%Plot live data
    if i > 1
        line([t(i-1) t(i)],[data(i-1) data(i)])
        drawnow
    end
fclose(s);

Thanks so much in advance,

Dan

[anil simsek]

I have Arduino code, I want to draw it instantly in matlab. Can you help me