A simple and easy USB soundcard hack for an Oscilloscope.
But please be careful, no protection is build in. Input signals up to 5V should be save.

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Download xoscope-2.2.tar.gz from:
https://sourceforge.net/projects/xoscope/

 $ tar -xvf xoscope-2.2.tar.gz
 $ cd xoscope-2.2cd

one has to fix the package (at least for Arch Linux), remove the line 37 from display.c. Open:

 $ nano display.c

and remove:

 void    *font;

Install the package:

 $ ./configure
 $ make
 $ sudo make install

Download micoscope-linux-1.0.tar.gz from:
https://sourceforge.net/projects/micoscope/
Unpack it and run it:

 $ tar -xvf micoscope-linux-1.0.tar.gz
 $ cd micoscope-linux-1.0/MicOscope/
 $ ./MicOscope

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Use a cheap USB soundcard. Open the housing and solder a wire to the ground and the signal pin.

Close the housing, that's i!

Best use is together with a breadboard For an simple input protection a decoupling capacitor and a potentiometer to attenuate the signal would be useful, too.

                  Poti
 Signal __100nF___| | |______GND
                    |
                    |____Mic Input

If you want build a better protection circuit here is a simple one:
http://xoscope.sourceforge.net/hardware/hardware.html
One can use 1N4148 diodes instead of the 1N914 diodes.

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