Graph grid lines are too prominent. I suggest reducing these to a dull gray.

Current reading should be differentiated more from other lines. (Consider colorblind users that cannot distinguish between them.) I suggest increased stroke width on the "current" reading.

The app worked right away with a single node built for serial as in https://github.com/RotorHazard/RotorHazard/blob/master/doc/USB%20Nodes.md . However, plugging it into a node on my D5V2 board with the same node code loaded did not work.

The D5V2 board connects the power inputs of all nodes, so all of them powered up when I connected one. I did remove the jumper so the Android device was not also trying to power the connected pi. My board is modded to the 'legacy' hardware addressing spec, but this should not trigger serial disabling.