%Find out which port the Arduino is using.  One way is to use the Arduino IDE.

 

% These are the commands you must execute in matlab to initialize for a virtual serial port COM5 on a PC.

 

% global a; a = serial(‘COM5′,’baudrate’,115200);fopen(a)

 

%Mac, for example:  global a; a = serial(‘/dev/tty.usbmodem1431′,’BaudRate’,115200); fopen(a)

function v = getvoltageDC(channel)

global a

switch channel

case 1

n1 = 19+128;

n2=0;

m1=1;

m2=0;

case 2

n1 = 18+128;

n2=0;

m1=1;

m2=0;

case 3

n1 = 17+128;

n2=0;

m1=1;

m2=0;

case 4

n1 = 16+128;

n2=0;

m1=1;

m2=0;

case 5

n1 = 0;

n2=19+128;

m1=0;

m2=1;

case 6

n1 = 0;

n2=18+128;

m1=0;

m2=1;

case 7

n1 = 0;

n2=17+128;

m1=0;

m2=1;

case 8

n1 = 0;

n2=16+128;

m1=0;

m2=1;

    otherwise

        disp(‘INVALID CHANNEL’)

end

pause(.02);

fwrite(a,[255,254,253,n1,0,0,n2,0,0]);

pause(.02);

fwrite(a,[255,254,253,n1,0,0,n2,0,0]);

pause(.02);

while a.BytesAvailable

    fscanf(a,‘%e’); % clear the buffer

end

fwrite(a,[255,254,253,0,0,0,0,0,0]);

pause(.01);

 

bdata=zeros([1,6]);

for i=0:5;

i=i+1;

r=fscanf(a,‘%e’);

bdata(i)=r;

end

bdata2=max(bdata(2)*2^8+bdata(3),bdata(5)*2^8+bdata(6));

 

if bdata2 < 2^15

    %disp(10*bdata2/(2^15-1))

    %bdata3=sprintf(‘%20f’,10.0*bdata2/(2^15-1));

    bdata3=10.0*bdata2/(2^15-1);

else

    %bdata3=sprintf(‘%20f’,-10.0*(2^16-bdata2)/2^15);

    bdata3=-10.0*(2^16-bdata2)/2^15;

    %disp(-10*(2^16-bdata2)/2^15)

end

v = bdata3;

end