I'm new to Arduino and since working years on Matlab I would like to merge some projects on Arduino.
I'm facing right now a problem in the serial communication between the two.
(I don't use simulink, and I don't want to)
What I would like is to transfer is a vector (10x1) to Arduino through serial.
It does work. It just doesn't do what you expect. So, lets adjust those expectations.
First, why are you using parseInt() when sending floating point values? Why are you storing the result integer values in a double array?
Second, since you failed to post your code correctly, it looks like you are trying to assign the integer value to the array, not to the ith element of the array. Are you actually storing the data correctly?
Third, opening the serial connection resets the Arduino. How much time are you allowing for the Arduino to reset? Can it reset, open the serial port, collect all the serial data, process it, and send data back in the time before you close the serial port again?
Fourth, does the program produce correct output if the data is sent from the Serial Monitor application?
It does work. It just doesn't do what you expect. So, lets adjust those expectations.
exactly. This because I really don't know very well Arduino.
why are you using parseInt() when sending floating point values? Why are you storing the result integer values in a double array?
because in principle I will send a vector from Matlab like this
x= [1.534e-14, 1e-5, 3.234]
And I thought that starting already with floating serial communication would save me time.
I've found on a tutorial this parseInt function and I thought it could work.
Second, since you failed to post your code correctly, it looks like you are trying to assign the integer value to the array, not to the ith element of the array. Are you actually storing the data correctly?
In Matlab yes. In arduino, I've no idea what I'm doing.
opening the serial connection resets the Arduino. How much time are you allowing for the Arduino to reset? Can it reset, open the serial port, collect all the serial data, process it, and send data back in the time before you close the serial port again?
mh.. I really don't know how much time I'm allocating for this.
I've found on a tutorial this parseInt function and I thought it could work.
To parse floats? Then, I suppose you'll use parseFloat() when you need to parse a bunch of ints in some other project...
In arduino, I've no idea what I'm doing.
Wel, posting code properly isn't rocket science.
Click the code icon (the far left one on the top row) and paste the code.
At least then we could seem the same thing you see with no italics.
I really don't know how much time I'm allocating for this.
Well, what part of your matlab code waits for something to happen?
pause(1)
All other parts are done as quickly as possible.
Now, is that one week, one hour, one minute, one second, or one millisecond?
double matlabData[3];
int i=0;
void setup()
{
Serial.begin(9600);
}
void loop()
{
while(Serial.available()>0) // if there is data to read
{
matlabData[i]=Serial.parseInt();; // read data
}
Serial.print(matlabData[0]);
Serial.print("\t");
Serial.print(matlabData[1]);
Serial.print("\t");
Serial.print(matlabData[2]);
Serial.print("\t");
Serial.println("");
}
And this is the Matlab code.
%% TESTS
clear all
clc
arduino=serial('/dev/cu.usbmodem1421','BaudRate',9600);
fopen(arduino);
x=[10;-1;0];
pause(1)
for i =1:max(size(x))
fprintf(arduino, '%f ', x(i));
%fwrite(arduino,x(1),'uint8');
end
y = fscanf(arduino, '%f')
fclose(arduino); % end communication with arduino
I didn't implement other things.
I have the pause(1) that means 1 sec. Matlab waits 1 sec.
Latest Arduino code
(I just changed the array into float, added the parseFloat())
again, whatever I send it's 0.
float matlabData[3];
int i=0;
void setup()
{
Serial.begin(9600);
}
void loop()
{
while(Serial.available()>0) // if there is data to read
{
matlabData[i]=Serial.parseFloat();; // read data
i++;
}
Serial.print(matlabData[0]);
Serial.print("\t");
Serial.print(matlabData[1]);
Serial.print("\t");
Serial.print(matlabData[2]);
Serial.print("\t");
Serial.println("");
}
I "partially" solved the problem with this Arduino code:
#define SIZE_DATA 3
float matlabData[SIZE_DATA] = {0}; //Not a bad idea to initialize it
void setup()
{
Serial.begin(9600);
Serial.setTimeout(1000); //set waiting time in ms (default: 1000ms) -> so, if you send something from Matlab, it will wait for 1000ms to be sure that nothing else will come…
}
void loop()
{
if (Serial.available() > 0) // if, not while (possibly an issue, to be confirmed
{
for (int i = 0; i < SIZE_DATA; i++) //Before you were not initializing your counter… So there was an overflow !
matlabData[i] = Serial.parseFloat();
Serial.read(); //clean serial buffer (read all remaining characters like “\r”)
//Print only if received data:
Serial.print(matlabData[0]);
Serial.print("\t");
Serial.print(matlabData[1]);
Serial.print("\t");
Serial.print(matlabData[2]);
Serial.print("\n");
}
}
I successfully send the inputs to arduino through serial monitor but now matlab cannot read or send. so I need now a Matlab routine to send correctly a vector to serial.
I finally had a result.
But still I want to improve it.
So in Arduino I have this:
#define SIZE_DATA 3
float matlabData[SIZE_DATA] ; //Not a bad idea to initialize it
void setup()
{
Serial.begin(9600);
Serial.setTimeout(10); //set waiting time in ms (default: 1000ms) -> so, if you send something from Matlab, it will wait for 1000ms to be sure that nothing else will come…
}
void loop()
{
if (Serial.available() > 0) // if, not while (possibly an issue, to be confirmed
{
for (int i = 0; i < SIZE_DATA; i++) //Before you were not initializing your counter… So there was an overflow !
matlabData[i] = Serial.parseFloat();
Serial.read(); //clean serial buffer (read all remaining characters like “\r”)
//Serial.flush();
//Print only if received data:
Serial.print(matlabData[0]);
Serial.print("\t");
Serial.print(matlabData[1]);
Serial.print("\t");
Serial.print(matlabData[2]);
Serial.print("\n");
}
}
in Matlab this:
clear all
clc
arduino=serial('/dev/cu.usbmodem1421','BaudRate',9600);
fopen(arduino);
y = fscanf(arduino, '%f');
x=[1;2;3];
for i = 1:3 memory
fprintf(arduino, '%f ', x(i));
end
y = fscanf(arduino, '%f')
x=[1.45;2.56;3.67];
for i = 1:3
fprintf(arduino, '%f ', x(i));
end
y = fscanf(arduino, '%f')
fclose(arduino); % end communication with arduino
As you can see I have 3 scanf... and 2 printf....why?
well..
Here the result on matlab:
Warning: Unsuccessful read: A timeout occurred before the Terminator was reached..
y =
1
2
3
y =
1.4500
2.5600
3.6700
If you cut the first fscanf and leave the others, still the first (with y=1,2,3) answer with the warning and then correctly scan the (y=1.45,2.56,3.67).
It seems that matlab start scanning before arduino sends the reply. am I wrong?
