The first robomagellan competition is in a few weeks so I’m working on conestoga quite a bit these days.
One of the issues I needed to resolve for conestoga was aligning the robot base and the digital compass on the stalk so that they both “point” in the same direction. Doing this has some difficulties, the robot drive and compass are generally not close to each other, you may have stray magnetic fields affecting the compass etc. I think I have come up with a way to align the compass and base that is very accurate, easy to use and very “old school”.
Using a “sun compass” that I can place level and flat against one of the wheels I use the suns azimuth angle for the day and time (from susdesign.com/sunangle) to point the robot exactly north then I rotate the stalk until the magnetic compass reads 0 degrees, at that point I lock the stalk so that it does not rotate. The robot base and magnetic compass at this point are perfectly aligned.