Below is an Arduino Oscilloscope I built using the Oscilloscope project from the Practical Arduino book. It's fairly low resolution, but for about 50 dollars (not including a computer) you can get a simple oscilloscope. Pretty neat. There is almost no build, and most of the work is done through the processing sketch on your computer. Essentially the arduino just spits out the values it receives on the Analog and Digital inputs as fast as it can to your computer. The analog inputs are slower then the digital ones, so this oscilloscope is probably a better logic analyzer. The processing sketch then graphs the different inputs.
The parts I used for the build are linked below. You really don't need any of it except an arduino and wire if you want to go really cheap, but I wanted something fairly sturdy to house everything in. And I wanted to have the potential to change out the probe types easily.
- Arduino (and USB cable to connect to Computer)
- Small Plastic Enclosure
- Probe Hooks
- RCA Jacks
- RCA Cable
- Male Header Pins
- Ribbon Cable
Below are Processing readouts from the 4 out of the potential 6 analog inputs. I was testing the signal of a digital sequencer I built similar to my sequencer I built over the summer. I used the Arduinoscope sketch for processing. If you decide to use that one, make sure that you have the older version of the Control P5 library in you sketch. I couldn't get the new version to compile with the arduinoscope sketch.