On the compass calibration

[seandepagnier]

Thanks for your answer. I guess I should have mentioned that I don't have the openplotter-integrated pypilot, but the TinyPilot connected to the OpenCPN plugin. So the IMU does not sit on the Raspberry that runs OpenPlotter, it sits on the Raspberry that runs Tinypilot. The openplotter does not show the presence of the TinyPilot IMU, and the openplotter calibration facilities don't apply to the remote TinyPilot. I guess that's how this is designed. At the risk of stating something obvious to others, allow me to summarize what I understand now so it can be validated and may be informative to others.

You can use the openplotter interface remote. Pass the tinypilot ip on the terminal of openplotter:
pypilot_calibration 192.168.14.1

But when I got it all hooked up, I still could not find a button to start the compass calibration facility in this plugin, only a tab that shows some calibration parameters and a checkbox to lock it. I had already suspected that there was some automatic, ongoing compass calibration: just start sailing and it calibrates itself, I had heard in one of the videos. Too bad because I really liked the orbital dots interface (just as a brain stimulator I guess :-) ). However it was consistent with the need to lock the calibration, so that tab made sense. Also, running the

It is normally automatically calibrating if it can. You need to have slowly turned in most orientations to update the calibration. So to start calibration you just need to make sure it isn't locked.

system on my workbench I had already noted that the compass reading was originally somewhat changeable, and I had attributed that to some automated calibration going on. I had not gotten to walking my pypilot in full circles though the workshop to finish this calibration; there are limits to my enthousiasm and on the boat that's far easier.

Indoors and around work bench is notorious for magnetic distortions. This will greatly influence calibration and compass accuracy. It is best to calibrate on the boat by actually rotating the boat once the sensors are mounted.