Read data from my computers sound card?

paul_4566

Read data from my computers sound card?

in Integration and Hardware • 2 years ago

Hi,

I was wondering if it is somehow possible to read data from the microphone input jack of my computer.
For example: I connect a mini jack plug to my arduino and let my arduino send messages over it, according to some sensor values. Then I want to be able to read these messages in processing.

I am asking this because when this is possible I want to try to connect a sensor to a phone using the mini jack input.

Grts

Replies(8)

Jesse Sco..

Re: Read data from my computers sound card?

2 years ago

Yes, it is possible.

Except you are asking two separate questions - connecting a mic into your mic-in jack and into an Arduino are very different processes (though the answer is the same).

paul_4566

Re: Re: Read data from my computers sound card?

2 years ago

Thanks,

What I mean is to make a serial connection from my arduino pins and solder the wires to a mini-jack plug, which I plug in my laptop's microphone input.

Do you have any suggestions on how to acces this in processing?
Or anyone who has experience with using the soundcard's input as serial connection?

Jesse Sco..

Re: Read data from my computers sound card?

2 years ago

Oh, ok.

Processing (or the libraries you would use in this case) would be expecting an audi buffer, full of audio bytes and samples...

You might have to take this into an Arduino program and then send the ensuing values as a string or a series of integers/floats to Processing.

That's my guess anyways. Could be wrong.

paul_4566

Re: Read data from my computers sound card?

2 years ago

Yeah,
keep in mind that the only connection between arduino and laptop would be the mini-jack cable, so no use of using the Arduino program.

So if it recieves a block signal (0s and 1s) it should be able to translate this into the original message right? I don't have any experience in using audio in processing, so I guess I just have to try out some things.

Jesse Sco..

Re: Read data from my computers sound card?

2 years ago

Do you mean that you are importing binary information and are expecting Processing to translate that back into audio ??!??

paul_4566

Re: Re: Read data from my computers sound card?

2 years ago

No, no audio involved at all here. Just simple messages or integers.

ptillemans

Re: Read data from my computers sound card?

2 years ago

You cannot directly rea ones and zeros from the soundcard input because the input is only for sounds, i.e alternating signals.

You need to "modulate" your bits as sounds and demodulate therm on the computer.

There are many ways to do that but an easy one i using pulses of different shapes for ones and zeroes

e.g :

1: 500ms HI 500ms LO

1: 500ms LO 500ms LO

when not transmitting turn the pin off. (or you'll need to do baseline tracking on the PC, plot the contents of the audiobuffer and you'll see what I mean, use a soundcard scope or audacity for example)

This is also known a "Manchester coding" ; http://en.wikipedia.org/wiki/Manchester_code

Use a voltage divider of 2k2 resistor and connect the centernode to the arduino with a 100k resistor to reduce the amplitude swing to about 50mV. put 220n to ground from the center of the voltage to limit noise from high frequency components of the switching.

This sound like fun!

cedrickie..

Re: Read data from my computers sound card?

2 years ago

as nobody asked this question so far. what the actual reason for using your linein of your laptop ?
is it part of the concept? cause if it is not, and you are just trying to send data, there are much better ways to do that...

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