by loboat @ instructables.com:
Oscilloscopes and Signal Generators are two essential electronics devices to create and test electronic circuits. Unfortunately, these devices are very expensives for students starting electronics, or makers who want use electronic circuits in their creations just once…
The idea of my project is to rethink your smartphone as a portable, powerful and secured platform, able to simulate an oscilloscope and a signal generator for your electronic circuits.
Here, your phone isn’t just an accessorize or an ordinairy remote control : it becomes the center of the project, and a tool to help you create better things in the future.
OscilloPhone: Use your Smartphone as an Oscilloscope / Signal Generator – [Link]