How can I use LPT-USB to trigger the output?

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Junghee 2013-12-9

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https://ww2.mathworks.cn/matlabcentral/answers/109137-how-can-i-use-lpt-usb-to-trigger-the-output

关闭： Walter Roberson 2013-12-10

在 MATLAB Online 中打开

I have worked on some codes to filter the sound.

I asked few days ago if anybody knows how to turn LED light on by using LPT-USB port and MATLAB.. but nobody answered.

I have filtered the sound and have a frequency spectrum.

According to that specified frequency, I need to trigger the output with LPT-USB port.

Following is what I did so far.

 % Reading wav file
 b=wavread('/Users/*******/Desktop/traffichonk.wav');
 % Selecting a portion (37s to 41s)
 b1=b(44100*37:44100*41);
 size(b1)
 % FFT algorithm
 n=176401;
 fs=44100;
 ts2=1/fs;
 tmax2=(n-1)*ts2;
 t2=0:ts2:tmax2;
 f2=-fs/2:fs/(n-1):fs/2;
 z2=fftshift(fft(b1));
 % Plotting the sample b1
 figure(1)
 plot(t2,b1)
 title('Plot of a Sound Sample');
 xlabel('time(s)');
 ylabel('Sound data');
 % Plotting the Frequency Spectrum
 figure(2)
 plot(f2,abs(z2))
 title('Frequency Spectrum');
 xlabel('Frequency Hz');
 ylabel('Amplitude');
 % After bandpass toolbox is used, alert saying "The variable 'Hbp' has been
 % exported to the command window.' will show up.
 b2=filter(Hbp,b1);
 z3=fftshift(fft(b2));
 % Plotting the frequency spectrum after filtering
 figure(3)
 plot(f2,abs(z3))
 title('Frequency Spectrum after Filtering');
 xlabel('Frequency(Hz)');
 ylabel('Amplitude');
 % Checking the sound
 soundsc(b2,44100)

I need to take live input in and send live output out... and I will use a microphone for a input device and LPT to USB port...(I found some info online- people said I could use LPT port to get output signal but I don't know if LPT-USB port is the right one)

Anyway, triggering the output or code for LPT-USB port.. anything is fine.

Please I'll appreciate any help.

Thanks