hey do you know of a arduino oscilloscope. thanks
Heres a couple:
http://accrochages.drone.ws/en/node/90
http://code.google.com/p/arduinoscope/
However, I tried them out and didn't find them that great, you can only see the very basics of the signal.
I ended up buying the LCD Scope from Seeed Studio. I bought the $49 assembled version, but you can get the kit for $33 if you are willing to build it yourself. Link is:
http://www.seeedstudio.com/depot/digital-storage-oscilloscope-with-panels-p-514.html?cPath=11
Quite impressed with it, and it's well worth the price. It's made a lot of projects much easier!
They've also got a new one which looks good, but I haven't used it so can't recommend it:
http://www.seeedstudio.com/depot/dso-nano-preorder-p-611.html?cPath=11