Sorry for the delay. I have to say - nice design! It's not particularly pretty but it looks functional, and that's what matters for a prototype.

First off - I've been searching for a data visualization program and found Paraview - it's not perfect, but it's pretty good, you can try it if you haven't (ask away if you have questions about the setup).
So, using that tool I went ahead and looked at the raw data set you've given from the 26th. I couldn't figure out much, but I think I identified a REM cycle between the 230 and 249 minute (I could be wrong, but it's at least something) . My assumption is that the waves that we saw represent breathing, and that in the interval I mentioned the first reading (I don't know right or left - the one with higher values) shows random fluctuations that may represent both breathing changes and eye-movements (characteristic for REM) .
About that raw data - why does one of the sensors return much higher values than the other? Are those direct readings, or have you processed the info somehow ? +At some points one sensor shows 0 . Any idea what that's about? And last but not least - any idea why one of the sensors (the one with lower values) shows apparently lower fluctuations than the other ? I had the idea to add a line to the graph (and I did) that's the ration between right/left reading, but it couldn't show anything because of the much lower amplitude in one of the sensors (it just mimicked the higher amplitude sensor).