Oscilloscopes and Arduino's

ARM Oscilloscope DSO-201 Nano (Mini 2.8in) Digital Oscilloscope

I was looking at digital oscilloscopes and kept seeing these really inexpensive (around $70) DSO-201 units showing up all over ebay.  I've only run into one problem so far in the last year where an oscilloscope would have helped me and it was a simple beginner mistake of not taking a tact switch's debounce into account while setting up the sampling rate.  A quick google search of my problem brought up tons of pages of people running into the same problem and their solutions so it was easy enough to fix.  Still, as I get deeper into building electronics it might be another helpful skill to have.  I tried doing a google search for oscilloscope arduino and found Accrochages webpage about using an Arduino to create a very limited, low end oscilloscope with similar capabilities as the DSO-201.  So I guess I have another project to build one of these evenings.  Good thing I just bought a bunch of super cheap Chinese Arduino UNO's.

I figure building a really simple oscilloscope with an Arduino will let me learn the basics of how to use one.  Plus if it does turn out to be useful I'll probably have a better idea of what kind of specs I'll need as there seems to be a big price difference depending on the sampling rate and number of inputs it has.  Although in the $400 price range they start to come with a few more bells and whistles.  Seems like that might be around the price range if I wanted one that would give me a little room to grow into it as I keep building bigger and ever more complicated circuits.

OWON SDS7102 100Mhz Oscilloscope 1GS/s 8" Color LCD USB FFT 2 + 1 Channel