Thread: HM55B Digital Compass - How do I program the controller to read it?
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Unread 12-03-2008, 01:34
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Re: HM55B Digital Compass - How do I program the controller to read it?
RyanN,

I would use the yaw-rate sensor before the compass. I saw a robot try to use a compass at a Seattle Robotics Society competition 8 years ago. It had a hard time getting though a maze (the Trinity Firefighting Building actually). All of us robot people stood around to try to figure out what was going on.

The best we could come up with is that the compass was reacting to the rebar in the floor. We even went so far as turning the maze to be in line with the rebar that did work when the robot moved in the “x” direction but it still did weird things in the “y”.

I then played around with a copy of his just to see how they work. Compasses sound like a good idea on a robot but in my playing around with them I could not get it working as well as I wanted. If you orientate your robot with a plain old compass around the four rose points and then read the electronic one you will find a great amount of deviation from 90 degrees. Of course over 360 they re-line up, but 90 degrees is not really 90 degrees to them.

-Jim