Humans can't detect magnetic fields, but we use devices that rely on magnets all the time. Motors, compasses, rotation sensors, and wind turbines, for example, all require magnets for operation. This ...

Both of these sensors use the MMC5983MA from MEMSIC - a highly sensitive triple axis magnetometer capable of sensing down to 0.4mG, enabling a heading accuracy of ±0.5°. Output rates of 1000Hz, ±8G ...