a few days ago i found this code in github and it's the best i found so far, so i've decided to spread this project as much as I can, for anyone who want a cheap oscilloscope around this is the best way! Let's start...
First, download processing. It's free Click here to download. You don't need to install anything, It runs like the Arduino IDE.
Now upload this code into your Arduino
After Run this code in Processing IDE
And then you just need to connect the Arduino analog pin 0 to the signal you want to read.
And It's done!
The Circuit I'll be measuring , it's a simple 555 timer circuit... that flashes a LED, parts list and wiring diagram:
1x 10k resistor
1x 1k resistor
1x 100nF electrolytic capacitor
check my YouTube video and watch it working. you can also visit my website for more projects and tips.