Serial Communication with Arduino

Hello,

I want that a serial communication with an Arduino.

They can communicate. I did it over the serial Connection without addons.

As next step I want to send with MatLab a "start send" message to the Arduino. At the moment the Arduino receive the message the controller should start the programm to send the data to matLab.

Sadly it doesnt work.

I hope that you can help me!

Thanks Lisa

Answer 1

[Mark Sherstan]

Your code should look something like this. Not the fprintf on the MATLAB side and the if (Serial.avilable() > 0 ) on the Arduino side.

MATLAB

% s is the serial port object...
fprintf(s, 'a'); % Send character to ardiuno
out = fscanf(s, '%40s\n'); % Read data from ardiuno 
split = strsplit(out, ','); % Seperate data based off commas
% Continue to process...

ARDUINO

void setup(){
  Serial.begin(115200);
  Serial.setTimeout(3);
  
  ... set up
}
void loop(){
... data acquistion and processing 
    
  if (Serial.available() > 0) {
            
  incomingString = Serial.readString();
    if (incomingString == "a\n") {
      Serial.print(data1); Serial.print(","); Serial.println(data2);
    }
  }
}

[Lisa-Sophie Baier]

Thanks for your answer! :)

I tried it now like this but it still seems not to work. Could you please take a look at it?

MATLAB

s = serial('COM13','BaudRate',9600);

s.InputBufferSize = 6; 

fopen(s);
fprintf(s,'g');

sFile = 'Elektroden.csv';

while(s.BytesAvailable <= 0)
    end

    mData = [];

    for i=1:6 %while if constant acquisition is needed. 

            sSerialData = fscanf(s); %read sensor
            flushinput(s);
            t = strsplit(sSerialData,'/t'); % same character as the Arduino code
            mData(i,1) = str2double(t(1)); 
           
    end    

    delete(instrfindall);    % close the serial port

    csvwrite(sFile,mData);   % save the data to a CSV file

    mData = csvread(sFile);  
%fclose(s);

ARDUINO

Serial.begin(9600);
  pinMode(A0,INPUT);
 
for (x = 0; x < 6; x++) {
    Serial.println(my_array[x]);
  }
  
}

void loop() {

  while(Serial.available()> 0){
  char start = Serial.readString();
    if(start == "g\t"){
      for (x = 0; x < 6; x++){
      Serial.print(my_array[x]);
      Serial.print('/t');
    }
  }
 }

Thanks for your help!

[Mark Sherstan]

To clarify you are reading 1 analog sensor and want to record that value in a .csv?

[Lisa-Sophie Baier]

Later on this should be my goal, yes.

For now I just want to send an Array from the Arduino to MatLab to work there with the data.

[Mark Sherstan]

I would reccomend having the Ardiuno just printing a single analog value and use MATLAB to create your array of data for processing. You will have to modify the code below depending on the size of your array but this is a fully working system that should push you in the right direction. You may also want to consider checking out this link.

ARDUINO

// Declare variables
int rawSensorVal;
String incomingString;

void setup(){
  // Initialize serial port
  Serial.begin(115200);
  Serial.setTimeout(3);
}

void loop(){
  // Read analog pin
  rawSensorVal = analogRead(A0);

  // Check if MATLAB has sent a character
  if (Serial.available() > 0) {
    incomingString = Serial.readString();

    // If character is correct send MATLAB the analog value
    if (incomingString == "a\n") {
      Serial.println(rawSensorVal);
    }
  }
}

MATALB

% Connect to serial port
s = serial('/dev/cu.usbmodem14101', 'BaudRate', 115200);
fopen(s);
pause(3);
fprintf("Connection established\n")

% Start a counter and timer
count = 0;
tic
startTimer = toc;

% Get data for 5 seconds
while (toc < startTimer+5)
  % Send character and receive data
  fprintf(s, "a");
  out = fscanf(s, '%d\n');

  % Display data to user
  fprintf("%d\n",out)

  % Increment counter
  count = count + 1;
end

% Display sample rate to user
endTimer = toc;
fprintf("Sample rate was: %0.2f Hz\n",count/(endTimer - startTimer))

% Remove serial port connection
fclose(s);
delete(s)
clear s