I'm in the design phase of a robotics project. I have pretty much done my prof of concept on a different platform and am building a new body with better motors and a bit more functionality. I was never able to get good results with my digital compass. I am positive it was because of the close proximity to the motors. The body was small enough that I couldn't get more than 5 or 6 inches away. This new body is an old 2.5 gallon popcorn tin like you see all over at Christmas, and a smaller tin above that as a "head". Both sections will have their own processors, the body controlling movement and collision avoidance, and the head will have environmental sensors, a display, GPS and compass.
he question is, how much does metal, like tin, effect a digital compass? Can it be inside? Is outside and mounted an inch above ok? What restrictions are there for use without too much accuracy lost? This will eventually be used with the GPS to figure headings to a waypoint so it does need to be more accurste than not.