error in opening MIT ecg database

hello,

I want read and plot ECG signal downloaded from MIT data base (.dat) i use the following codes:

clear all
clc
close all
[filename, pathname] = uigetfile('*.dat', 'Open file .dat');% only image Bitmap
if isequal(filename, 0) || isequal(pathname, 0)   
    disp('File input canceled.');  
   ECG_Data = [];  
else
fid=fopen(filename,'r')
end;
time=10;
f=fread(fid)
Orig_Sig=f(1:length(f));
%plot(Orig_Sig(1:2:length(f)))
plot(Orig_Sig(1:2:4000))

i get the following error:

Error using fread Invalid file identifier. Use fopen to generate a valid file identifier.

how i can read these data?

thank in advance

[Star Strider]

If you are using the PhysioBank ATM to access the files, it is much easier to request the MATLAB ‘.mat’ file than the other formats to use them in MATLAB. Then you can just load them. Be sure to download the accompanying ‘.info’ file as well, since it has the sampling frequency and other information you will need to process your signals

Answer 1

[Walter Roberson]

fd = fopen( fullfile(pathname, filename), 'r')

[anas qazaz]

thank Mr Walter my data stored in E drive , bin file, the data file name 102.dat how i can use your code?

[Walter Roberson]

[filename, pathname] = uigetfile('*.dat', 'Open file .dat');
if isequal(filename, 0) || isequal(pathname, 0)   
    disp('File input canceled.');  
   ECG_Data = [];  
else
  fid = fopen( fullfile(pathname, filename), 'r')
  time = 10;
  f = fread(fid)
  Orig_Sig=f(1:length(f));
  plot(Orig_Sig(1:2:4000))
end

You are requesting to open a file that is not in your current directory. uigetfile() returns the directory and filename in different outputs -- so it does know which directory you requested but the directory is not built into the filename output. You then tried to open using just the filename output without putting together the information uigetfile() returned about the directory.