[hooeezit]

Looks like you need more than just an oscilloscope - you need a trend recorder. The DSO Nano is a great for casual work, but if you have some electronics skill, you can easily build an attenuator to hook into your laptop's microphone or line-in (1 channel or 2 channel) jack and record the signal for trend analysis. You can also use an MP3 player with recording abilities as long as it records to a WAV file, not MP3 directly.

Take a look at these links: http://www.ledametrix.com/oscope/index.html http://www.zelscope.com/

And if you grow out of it, this is a very hackable, real oscilloscope for an affordable price: http://www.dealextreme.com/details.dx/sku.30573

Here is info on hacking the Rigol to make it a 100MHz scope: http://mightyohm.com/blog/2010/03/rigol-ds1052e-50mhz-to-100...