Arduino Matlab serial data streaming

Dear all,

I am working on a project that use Matlab to read analog data from Arduino board CONTINUOUSLY. At the first step, the Arduino code is programming to send a number 3 to serial port (COM11) continuously. I then would like to read the number 3 from a matlab code in a continuous manner as well. Attached here are a code for arduino and a code for matlab. My problem is that everything I run the matlab code, it gave me two errors. But response display the number 3. I guess the problem starts to occur when I prepare the data stream. Please let me know how I can fixt it. Thanks a lot.

The error message:

    response =

3

Error using serial/subsasgn (line 153) BytesAvailableFcnMode cannot be set while OBJ is open.

Error in serialDataStream (line 112) obj.BytesAvailableFcnMode='byte';

Matlab code

      function serialDataStream
  % SERIALDATASTREAM is a design pattern for a function to receive and
  %  process a continuous stream of data from a device connected to a USB or
  %  serial port. This function does not execute as written; it includes
  %  explanations and examples for all of the steps required to capture data
  %  which is transmitted continuously over a USB or serial interface. It
  %  uses some advanced features of the MATLAB serial port interface and has
  %  been used for streaming high data rates up to 1.5 MB/sec. Features for
  %  Windows, Mac OS X, and Linux are included. The MATLAB Instrument Control
  %  Toolbox is not required.
  %
  % Most USB drivers include the capability to act as a "Virtual Serial
  %  Port" or "Virtual COM Port" (VCP). This capability is used for the
  %  MATLAB interface, so ensure that your device drivers have this
  %  capability. All drivers for OS X and Linux include this feature. In
  %  Windows, VCP is sometimes a separate feature, or requires an additional
  %  installation step. This code was developed using FTDI USB interfaces,
  %  but it is not specific to FTDI.
  % 
  % This code does not execute as it is written; it is a design pattern. Read
  %  it and modify it for your needs.
  %
  %
  % Matthew Hopcroft
  % [e-mail]
  % Mar2012 v1.1 update description
  % Jun2011 v1.0
  %

delete(instrfindall);

%%1. Identify the serial port
% Serial ports have different system identifiers, depending on the
%  operating system.

% Windows uses "COM" ports. The system assigns a new COM port for each new
%  device that is connected. The numbering can be modified using the Device
%  Manager. Typically COM port numbers 1-3 are reserved for system use.
USBport = 'COM11';
% Mac OS X uses Unix /dev entries. The name of the device begins with 
%  "/dev/tty.usbserial-" followed by the serial number of the USB device
%  which is connected.
% USBport = '/dev/tty.usbserial-FTDI5463';
% Linux (Ubuntu, Debian) uses Unix /dev entries. The name of the device
%  begins with "/dev/ttyUSB" followed by a number. Other Linux distributions
%  may use different conventions.
% USBport = '/dev/ttyUSB0';

% Optional:
% In Windows, you can use the system command "mode" to list available COM
%  ports, but it does not give any information about which device is connected.
%[mstat, availableCOMports] = system('mode'); % Windows
% In OS X or Linux, you can determine the port name by examining the /dev
% entries:
%availableDevices = ls('/dev/tty.usbserial-*'); % OS X
% availableDevices = ls('/dev/ttyUSB*'); % Linux

%%2. Create the serial object
% The serial port object represents the connection to the device. In the
%  MATLB documentation, this variable is typically called "obj". You will
%  read and write data from your USB device through the serial port object.
obj=serial(USBport);

% You will have to set the serial port settings according to your device
%  requirements. Some common settings are shown here. See the MATLAB
%  Documentation for all possibilities for your device.
%
% The baudrate is the data transmission rate in bytes per second
% Most USB devices can support a baudrate of up to 1.5e6, but some
%  operating systems do not support "nonstandard" baudrates for serial ports.
% "standard" baud rates include:
% 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200, 128000, 230400, 460800, 921600
obj.BaudRate=9600;
% Termination character for data sequences
obj.Terminator='CR';
% The byte order is important for interpreting binary data
obj.ByteOrder='bigEndian';

%%3. Setup your device
% Your USB device may require some setup through interface commands. To
% send and receive commands, use fprintf(obj) and fscanf(obj).

% The serial port object must be opened for communication
if strcmp(obj.Status,'closed'), fopen(obj); end

% Send a command. The terminator character set above will be appended.
fprintf(obj,'WAKEUP');

% Read the response
response = fscanf(obj);
response

%%4. Prepare for the data stream
% The data arriving from the USB device will be handled by a serial port
%  function which is called automatically when a certain number of bytes
%  have been received in the input buffer. Your serial port function will
%  remove the data from the buffer and process it. Adjust the buffer size
%  and the function byte count to suit your application.

% The input buffer must be large enough to accomodate the amount of data
%  that will be received while your program is busy processing previously
%  received chunks of data. Having a buffer that is too large is not a
%  problem for most modern computers.
obj.InputBufferSize=512; % in bytes
% The "BytesAvailableFcn" function will be called whenever
%  BytesAvailableFcnCount number of bytes have been received from the USB
%  device.
obj.BytesAvailableFcnMode='byte';
obj.BytesAvailableFcnCount=1; % 1 kB of data
% The name of the BytesAvailableFcn function in this example is
%  "getNewData", and it has one additional input argument ("arg1").
obj.BytesAvailableFcn = {@getNewData,arg1};

% Use the serial port object to pass data between your main function
%  and the serial port function ("getNewData").
% You could include things like total number of data points read,
%  timestamps, etc, here as well.
obj.UserData.newData=[];
obj.UserData.isNew=0;

%%5. Process the incoming data
% In this example, we use a loop to plot the data stream that is sent by
% the USB device.

% A global variable is used to exit the loop
global PLOTLOOP; PLOTLOOP=1;
% Initialize data for plotting. "plotWindow" will be the length of the
%  x-axis in the data plot.
plotData=zeros(plotWindow);
newData=[];
% Create figure for plotting
pfig = figure;
% This allows us to stop the test by pressing a key
set(pfig,'KeyPressFcn', @stopStream); 

% Send commands to the device to start the data stream.
fprintf(obj,'START');

while PLOTLOOP

      % wait until we have new data
      if obj.UserData.isNew==1

          % get the data from serial port object (data will be row-oriented)    
          newData=mr.UserData.newData';

          % indicate that data has been read
          mr.UserData.isNew=0;

          % concatenate new data for plotting
          plotData=[plotData(size(newData,1)+1:end,:); newData];

          % plot the data
          plot(pfig,plotData);

          drawnow;
      end

      % The loop will exit when the user presses return, using the
      %  KeyPressFcn of the plot window

end

%%6. Finish & Cleanup
% Add whatever commands are required for closing your device.

% Send commands to the device stop the data transmission
fprintf(obj,'STOP');

% flush the input buffer
ba=get(obj,'BytesAvailable');
if ba > 0, fread(mr,ba); end

% Close the serial port
fclose(obj);
delete(obj);

return

%%Data Processing Function
function getNewData(obj,event,arg1)
% GETNEWDATA processes data that arrives at the serial port.
%  GETNEWDATA is the "BytesAvailableFcn" for the serial port object, so it
%  is called automatically when BytesAvailableFcnCount bytes of data have
%  been received at the serial port.

% Read the data from the port.
% For binary data, use fread. You will have to supply the number of bytes
%  to read and the format for the data. See the MATLAB documentation.
% For ASCII data, you might still use fread with format of 'char', so that
%  you do not have to handle the termination characters.
[Dnew, Dcount, Dmsg]=fread(obj);

% You can do some initial processing of the data here in this function. 
%  However, I recommend keeping  processing here to a minimum and doing
%  most of the work in the main loop for best performance.

% Return the data to the main loop for plotting/processing
if obj.UserData.isNew==0
    % indicate that we have new data
    obj.UserData.isNew=1; 
    obj.UserData.newData=Dnew;
else
    % If the main loop has not had a chance to process the previous batch
    % of data, then append this new data to the previous "new" data
    obj.UserData.newData=[obj.UserData.newData Dnew];
end

return

%% Loop Control Function function [] = stopStream(src,evnt) % STOPSTREAM is a local function that stops the main loop by setting the % global variable to 0 when the user presses return. global PLOTLOOP;

if strcmp(evnt.Key,'return') PLOTLOOP = 0; fprintf(1,'Return key pressed.'); end

return

% % % %

Arduino Code

    void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

void loop() {

if (Serial.available()){
Serial.println(3);

delay(100);        // delay in between reads for stability
}
}

[Nishant Kumar]

try this code

[Patrice Gill]

did you solve this?