currently i working on plotting a graph of rpm sensor on matlab but unfortunately when i run the plotting coding in Matlab it was failed.It said 'Warning: Unsuccessful read: Matching failure in format.' please help me,i dont know what is the problem

volatile int rpmcount = 0;
int rpm = 0;
unsigned long lastmillis = 0;

void setup(){
 Serial.begin(9600); 
 attachInterrupt(0, rpm_car, FALLING);//interrupt cero (0) is on pin two(2).
}

void loop(){

   if (millis() - lastmillis == 1000){  //Uptade every one second, this will be equal to reading frecuency (Hz).

   detachInterrupt(0);    //Disable interrupt when calculating

   rpm = rpmcount * 60;  // Convert frecuency to RPM, note: this works for one interruption per full rotation. For two interrups per full rotation use rpmcount * 30.

   Serial.print("RPM =\t"); //print the word "RPM" and tab.
   Serial.print(rpm); // print the rpm value.
   Serial.print("\t Hz=\t"); //print the word "Hz".
   Serial.println(rpmcount); //print revolutions per second or Hz. And print new line or enter.

   rpmcount = 0; // Restart the RPM counter
   lastmillis = millis(); // Uptade lasmillis
   attachInterrupt(0, rpm_car, FALLING); //enable interrupt
    }
  }

void rpm_car(){ // this code will be executed every time the interrupt 0 (pin2) gets low.
  rpmcount++;
}

Answer 1

[Image Analyst]

This is C or Java code, not MATLAB code. Use MATLAB instead.

[Nazrin Zaini]

i run this code above in arduino and it work well with no error.below is my matlab code.previously i use ldr sensor(run ldr coding in arduino) and use this plotting coding in matlab.and its working well.but when i working on rpm sensor and run the coding above in arduino and use this plotting coding in matlab below.its said 'Warning: Unsuccessful read: Matching failure in format.' please help me,i dont know what is the problem'

delete(instrfindall);

clear all; clc; close all;

% Try-catch is to prevent Matlab from crashing when the program is finished
try
% Initialize serial port
s = serial('COM8');
%set(s, ‘ Terminator’, ‘LF’); % Default terminator is \n
set(s,'BaudRate', 9600);
set(s,'DataBits', 8);
set(s,'StopBits', 1);
fopen(s);
s.ReadAsyncMode = 'continuous';

% Various variables
numberOfDatas = 100;
data = zeros(1, numberOfDatas);
i = 1;

% Main graph figure
figure(1);
hold on;
title('Incoming Data from External Device');
xlabel('Data Number');
ylabel('Analog Voltage (0-1023)');

% Start asynchronous reading
readasync(s);

while(i<=numberOfDatas)  

      % Get the data from the serial object
      data(i) = fscanf(s, '%d');

      % Plot the data
      figure(1);
      plot(i, data(i), 'm*');

      % Ensure there are always 10 tick marks on the graph
      if(i>10)
         xlim([i-10 i]);
         set(gca,'xtick',[i-10 i-9 i-8 i-7 i-6 i-5 i-4 i-3 i-2 i-1 i])
      end

      % Draw and flush
      drawnow;

      %Increment the counter
      i=i+1;

end

% Give the external device some time…
pause(3);

return;

catch

% Some of these crash the program – it depends. The serial port is left
% open, which is not good.                                              
stopasync(s);
fclose(s); % bad
%delete(s);
%clear s;

fprintf(1, 'Sorry, you"re going to have to close out of Matlab to close the serial port\n');

return

end

[Image Analyst]

Sorry, but I don't have an arduino so I can't help.

[melisa samad]

Hi, Nazrin Zaini. do you know how to code the speed at matlab?

[Walter Roberson]

You have the Arduino sending "RPM =" and "Hz=" but your MATLAB code is expecting only numeric values.

Answer 2

[Osama Yassin]

Hi, Nazrin Zaini .. did get the solution about attachInterrupt function in matlab?