Let’s turn Raspberry Pi into an analogic/digital measurment tool with BitScope Micro, the most recent product of the BitScope tools generation. As hinted by the name, its calling is the measurement of digital signals. The software is available for the GNU/Linux, Windows and Mac/OS X platforms.

http://www.open-electronics.org/turn-your-raspberry-pi-in-an-oscilloscope-with-bitscope/