Question regarding Hall sensor/effect wrt q(VxB)

[Lighthouse]

If a make some basic assumptions about a standard hall probe I find, quite expectedly that the velocity of the charge carriers is of the order 10-5 m/s. In a hall probe measuring the Earth's magnetic field like the one in my phone this should be the velocity of the charge carriers with respect to the Earth's field (using q(VxB)). But it isn't not if I am walking around. If I include the velocity I'm giving the charge carriers then the sensor shouldn't work, but it does. Why is that?


I think its because the hall effect creates a compensating voltage across the voltage sensor as well as the hall sensor since both are moving in the same way but I'm not sure if that's easy to do. Ie is the hall voltage material dependent?

 

[gtoguy97]

The Hall effect is based on the fact that a charge moving through a magnetic field will experience a force perpendicular to both the velocity and the magnetic field. When a current passes through a metal, the charge carriers (electrons or holes) are subject to a Lorentz force which causes them to drift in a direction perpendicular to both the electric field and magnetic field. This is what causes a voltage drop across the sensor. The Hall effect is independent of the velocity of the charge carriers, so it does not matter if you are walking around or not. The only thing that matters is the strength of the magnetic field and the magnitude of the current passing through the Hall Sensor.