Quote:
Originally Posted by Matt H.
I'd be very careful using any kind of compass on your robot--the magnetic fields produced by your motors and even in the straight wiring connections of your robot will produce a large magnetic field simply because of the amperage they are using. The earths magnetic field is only .05 mT which will easily be overwhelmed by the magnetic fields created by your robot.
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As a counterpoint, I've used the Devantech CMPS03 digital compass on a non-FIRST robot to do outdoor navigation. The compass is mounted about 18 inches away from my drive motors (a pair of Taigenes), on top of a piece of PVC. I expected that I would encounter magnetic field issues, but the output values don't seem to vary by more than a degree or two when I turn the motors on and off. To be fair, Taigenes don't draw quite as much current as CIMs, but I would venture that using a digital compass in this application is quite feasible, so long as you make some effort to keep the sensor reasonably isolated from your motors and power leads.