Need to turn LED lights on by using LPT port - So far, used FFT and Bandpass filter

Hello

Following is what I have 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)

-> NOW

According to my research, I figured I can use LPT port to connect LED lights to the computer as an output source.

I need a code that can trigger the output based on what I have..

Right now, I'm trying to use 1 LED light to just make it work, but my actual goal is to use 6 LED lights and 6 microphone sensors.

When individual microphone sensor senses the sound, relevant individual LED light is suppose to light up.

If anybody knows how to program either one, please help me out.

Thank you A LOT in advance!!

- Bri

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/newsreader/view_thread/289908

https://www.mathworks.com/matlabcentral/answers/90080-triggering-a-slave-target-with-parallel-port

And if you have access to the Data Acquisition Toolbox, see http://www.mathworks.com/matlabcentral/answers/22387

[Junghee]

Hi thanks for your answer.

I was actually looking for somewhat exact way or code that can help me.

I'm not a professional who knows how to implement a code into my own..

I kind of researched on these already on my own so yes I did saw most of your recommendations.

But I still don't know what to do with these and that's why I asked here.

Reading them didn't make me understand what those codes actually do..... :(

My LED light doesn't have to turn on for millisecond.

It actually has to last as long as the sound is on.

Live input to live output.

So far, I watched youtube tutorials and taught myself how to do FFT and filter stuff but I couldn't find related video for triggering the output with live sound input..

[Walter Roberson]

Do you have the Data Acquisition Toolbox ?

[Junghee]

nope.. I don't see it