There are a lot of examples of sensory augmentation like what you're talking about with magnets. Basically the brain seems to be able to adapt to almost any sen

There are a lot of examples of sensory augmentation like what you're talking about with magnets. Basically the brain seems to be able to adapt to almost any sensory input. There's a company that was testing a device that turned the pixels on a low res camera into electrical impulses to a tongue mounted sensor plate. There was a study where people had a belt fitted with vibrating motors and a compass so that the part of the belt facing north always vibrated. The people in the study begin to feel where north was. There was a another study where an input from an ultrasonic rangefinder on a scalpel was converted to an electrical stimulation and surgeons could feel how close their scalpel was to a surface.