How can I plot real time graph from i2c data that is transmitted over bluetooth?

I am trying to plot a real time graph on MATLAB of wirelessly transmitted digital sensor data(I2C). The structure of the system is as follows: MCP9808(Digital Temperature sensor) -> Arduino Uno with HC-05(Bluetooth Module) -> MATLAB. I managed to plot a real time graph of the analogue temperature sensor.

The following is Arduino code which receives digital temperature value and transmits over to MATLAB

#include <Wire.h>
#include <SoftwareSerial.h>
SoftwareSerial BTSerial(4, 5); 

void setup()
{
  Serial.begin(9600);
  Wire.begin(); 
}

void loop()
{
  uint16_t t;

    Wire.beginTransmission(0x18);
    Wire.write(0x05);
    Wire.endTransmission();
    delay(100); 
    Wire.requestFrom(0x18, 2);
    t = Wire.read();
    t <<= 8;
    t |= Wire.read();  

    float temp = t & 0x0FFF;
    temp /=  16.0;
    if (t & 0x1000) temp -= 256;

    Serial.println(temp);
    BTSerial.println(temp);
    delay(1000);
  }

and this is the MATLAB code:

clear all; clc;
delete(instrfindall)
instrreset;
b = Bluetooth('YONG',1);
fopen(b);

figure
h = animatedline;
ax = gca;
ax.YGrid = 'on';
stop = false;
startTime = datetime('now');

while ~stop
    a = str2num(fscanf(b));
    % Get current time
    t =  datetime('now');
    % Add points to animation
    addpoints(h,datenum(t),a)
    % Update axes
    ax.XLim = datenum([t-seconds(15) t]);
    datetick('x','keeplimits')
    drawnow
end

fclose(b);

It will be greatly appreciated if I could get some tips on this. Thank you in advance.

[Walter Roberson]

What difficulty are you seeing on the MATLAB side?

[Yong Kim]

I can't graph any values that I have received from digital sensor via bluetooth, the error I get is

Warning: Unsuccessful read: A timeout occurred before the Terminator was reached. 
Error using matlab.graphics.animation.AnimatedLine/addpoints
Argument Y must be a vector.

Error in untitled2 (line 19)
    addpoints(h,datenum(t),a)

Could you possibly help me on this please?

Thank you

Answer 1

[Sachin Kumar]

The MATLAB code works fine here. The problem is in the arduino code, you need to initial "BTSerial" using below function in your setup(){}:

BTSerial.begin(baud_rate);

You can use disp(a) in MATLAB code to check whether the value received in MATLAB is proper or not.

[Yong Kim]

Thank you so much, that was very silly of me!

[Technical]

CAN I PLOT LIVE STREAMING DATA IN TO MATLAB?..DATA FROM AN ANALOGOUS SENSOR. ARDUINO UNO. PLEASE HELP.I AM USING MATLAB MOBILE

Answer 2

[Technical]

In a simplest way to get plot of an analogous sensor data from arduino to android through blue tooth module as like as serial plotter.? How to