How to control keyboard in matlab using the data from the serial port?

Iam working in an Arduino project where it sends data to the serial port and the matlab receives it and a key press is done according to the data.

 % code
import java.awt.Robot;
import java.awt.event.*;
robot = Robot();
%code
s=serial('COM5');
set(s,'BaudRate', 9600);
set(s,'DataBits', 8);
set(s,'StopBits', 1);
fopen(s);
s.ReadAsyncMode = 'continuous';
data=0;
%code
while 1
    data=fscanf(s);
    if data==1
        robot.keyPress(java.awt.event.KeyEvent.VK_W);
    end
    display(data);
end
fclose(s);

I have uploaded the my Matlab file iam currently using. Where if the data==1 the "W" key should be pressed by matlab. The code key press event code works well when it is no in if condition. Need a solution please.

Answer 1

[Walter Roberson]

You are using fscanf(s) . The default format for fscanf serial is %c , which is character. In order for a character to compare equal to 1 it would have to be char(1), the Start of Header (SOH) character.

If you want to receive numeric data then you should specify a numeric format for the fscanf(). If you want to compare to the digit 1 then you need to compare to the digit 1, which is '1', char(49), not 1

[Mohamed Fazil]

But also it is not working.

    % code
data=fscanf(s);
    if data=='1'
        robot.keyPress(java.awt.event.KeyEvent.VK_W);

    end

This is what i did.Is there any prob with robot.keypress?

[Walter Roberson]

Where should the 'W' go? You have not told the robot to move to any particular position. Is the W being directed to the MATLAB command line? Is it being directed to a WindowKeyPressFcn callback of a MATLAB figure?

[Mohamed Fazil]

I want 'W' to just simply be pressed by when ever that data is equal to 1. how to do that.

[Walter Roberson]

Which process outside MATLAB, or which part of MATLAB do you want to read the "W", or do you want the W sent over the serial port ? If you "just" want it to be pressed, then how do you know if it is doing anything or not?

[Mohamed Fazil]

I am making a game controller project using arduino and matlab.So when ever the data from the arduino is 1 i want the 'W' key in the keyboard to be triggered.

[Walter Roberson]

Your code looks like it should do that. You will want to use the java robot to move your cursor on top of the game being controlled.

If your code does not seem to be working yet, then put in a breakpoint after the fscanf() of the data and

disp(double(data))

the result will be the underlying character code of what was received; for example the character for the digit 1, '1' would be code 49.

[Mohamed Fazil]

Nope its not working i tried,

[Walter Roberson]

You are in MATLAB, your point of focus is probably still MATLAB, the robot is going to be trying to press the 'W' on top of whatever has focus in MATLAB, quite possibly a graphics figure. If you do not have robot code to move the cursor away to the game then you will have this problem.

What is the result of the double(data) after the fscanf() ?

[Mohamed Fazil]

data =

    49    13    10

i got something like this.I used a note pad keeping it near by and made the cursor to go on top of it and click. But also it dint work.

    % code
import java.awt.Robot;
import java.awt.event.*;
robot = Robot;
mouse = Robot;
s=serial('COM5');
set(s,'BaudRate', 9600);
set(s,'DataBits', 8);
set(s,'StopBits', 1);
fopen(s);
s.ReadAsyncMode = 'continuous';
________________________________________________________
mouse.mouseMove(0,0);
for i = 0:250 
    mouse.mouseMove(60,i);
    pause(0.00001);
end
mouse.mousePress(InputEvent.BUTTON1_MASK);
pause(0.00001);
mouse.mouseRelease(InputEvent.BUTTON1_MASK);
____________________________________________
while 1
    data=fscanf(s);
    data=double(data);
    display(data);
    if data=='1'
       robot.keyPress(java.awt.event.KeyEvent.VK_W);
    else
        try
            robot.keyRelease(java.awt.event.KeyEvent.VK_W);
        end
    end
end
fclose(s);

[Walter Roberson]

49 13 10 is '1' followed by carriage return followed by linefeed. You should configure your serial port to use CR/LF termination, and you should use fgetl() instead of fscanf(). The result of fgetl() will be characters with no line terminator. You can then strcmp() that to '1' (strcmp() is safer than == for characters in case the input is not exactly one character).