Data acquisition from USB Joystick - MAC OS

Hi.

For the project I am working on, I am trying to read in the 3-axis xyz values, as well as throttle and buttons, form my joystick. My problem is that I do not know how to persuade MatLab to do that.

I've seen that some out there published some self-made tools, comprising a mex file, to get that done. That might well work on WIndows but I have a Mac os. And that does not work on macs.

So I have a USB 4 axis joystick. I know that my comp can successfully interface with the external hardware (tried it when running google earth's flight sim, piloting trough ystick- pretty awesome!)

How can I explain matlab to read instantaneous values from the joystick, connected at my USB slot?

Than you so much. Marco

[Christopher Berry]

Why do you say that using mex files wont work on a Mac?

[Marco]

My knowledge of mex files is nearly zero, so there migh be something wrong in my original statement. However, I see that when trying to compile the *.c file, some windows related stuff is called in.

What follows is the *.c file:

// // mat_joy.c // MATLAB Interface for Joysticks // Author: Stanislaw Adaszewski, 2012 //

#include mex.h #define WIN32_LEAN_AND_MEAN #define WINVER 0x0500 #include windows.h #include mmsystem.h

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) { int joyId; JOYINFO joyInfo; mwSize sizePos[] = {3,1}; mwSize sizeBut[] = {16,1}; double *pos; double *but; int i;

    if (nlhs != 2 || nrhs != 1 || mxIsEmpty(prhs[0]) || mxGetNumberOfElements(prhs[0]) != 1 || (joyId = (int) mxGetPr(prhs[0])[0]) < 0 || joyId > 15) {
        mexErrMsgTxt("Usage: [position, buttons] = mat_job(joystick_id), where:\n\njoystick_id - joystick identifier (0-15),\nposition - list of joystick position in X, Y and Z axis,\nbuttons - list of 16 joystick button states (missing buttons are always zeros)");
    }

    joyGetPos(joyId, &joyInfo);

    plhs[0] = mxCreateNumericArray(2, sizePos, mxDOUBLE_CLASS, mxREAL);
    plhs[1] = mxCreateNumericArray(2, sizeBut, mxDOUBLE_CLASS, mxREAL);

    pos = mxGetPr(plhs[0]);
    but = mxGetPr(plhs[1]);

    pos[0] = ((double) joyInfo.wXpos - 32767) / 32767;
    pos[1] = ((double) joyInfo.wYpos - 32767) / 32767;
    pos[2] = ((double) joyInfo.wZpos - 32767) / 32767;

    for(i = 0; i < 16; i++) {
        but[i] = (joyInfo.wButtons >> i) & 1;
    }
}