function [S] = readsens(filename, start, stop)

%READSENS Read sensor datafile and put it in a matrix.
%         [S] = readsens(filename, start, stop) reads the data into matrix S
%         from sample <start> to sample <stop>, or until the end of file.
%
% 							Kristof Van Laerhoven, kristof@comp.lancs.ac.uk

    path = [];

	if ~exist('filename'),
		[filename path]= uigetfile('*.txt','Pick a file:')
	end;

	fid = fopen([path filename],'r');

	i = 1;

    S = [];    
    
	while ~feof(fid) & stop>i,

        % read one vector into matrix S.
		Tmp = fgetl(fid);
		
        % check if we really have to convert this (start)
        if start<i,
            Tmp2 = str2num(Tmp);
            if size(Tmp2,2)~= size(S,2) & ~isempty(S),
                disp(['error at line ' int2str(i)])
            else
                % convert to vector
                S = [S; Tmp2];
                i = i + 1;
            end        
        else            
            i = i + 1;
        end        
	end
	fclose(fid);
end