A magnetic field sensor for sensing a movement of a ferromagnetic object, the magnetic field sensor comprising: a magnet; a semiconductor substrate having first and second surfaces (302a, 302b), the semiconductor substrate proximate to the magnet and at a position between the ferromagnetic object and the magnet, the semiconductor substrate comprising: first and second orthogonal axes on the first opposing surface of the substrate intersecting at a coordinate axes point; and a substrate region upon the first opposing surface of the substrate, the substrate region proximate to and surrounding the coordinate axis point, wherein magnetic fields generated by the magnet within the substrate region are substantially perpendicular to the first and second surfaces (302a, 302b) of the semiconductor substrate in the absence of the ferromagnetic object, the magnetic field sensor further comprising: a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the substrate region, wherein the first magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first orthogonal axis, wherein a center of the first magnetic field sensing element is disposed along the first orthogonal axis; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the substrate region, wherein the second magnetic field sensing element comprises an axis of maximum sensitivity substantially perpendicular to the axis of maximum sensitivity of the first magnetic field sensing element and substantially parallel to the first surface of the semiconductor substrate, wherein a center of the second magnetic field sensing element is disposed along the second orthogonal axis; and an electronic circuit disposed upon the substrate, coupled to the first and second magnetic field sensing elements (404, 406) and configured to sum first and second signals from the first and second magnetic field sensing elements (404, 406) to generate a combined signal, and configured to compare the combined signal with a reference signal to generate a two-state signal having a change of state when the ferromagnetic object moves closer to the semiconductor substrate than a predetermined distance. a magnet; a semiconductor substrate having first and second surfaces (302a, 302b), the semiconductor substrate proximate to the magnet and at a position between the ferromagnetic object and the magnet, the semiconductor substrate comprising: first and second orthogonal axes on the first opposing surface of the substrate intersecting at a coordinate axes point; and a substrate region upon the first opposing surface of the substrate, the substrate region proximate to and surrounding the coordinate axis point, wherein magnetic fields generated by the magnet within the substrate region are substantially perpendicular to the first and second surfaces (302a, 302b) of the semiconductor substrate in the absence of the ferromagnetic object, the magnetic field sensor further comprising: first and second orthogonal axes on the first opposing surface of the substrate intersecting at a coordinate axes point; and a substrate region upon the first opposing surface of the substrate, the substrate region proximate to and surrounding the coordinate axis point, wherein magnetic fields generated by the magnet within the substrate region are substantially perpendicular to the first and second surfaces (302a, 302b) of the semiconductor substrate in the absence of the ferromagnetic object, the magnetic field sensor further comprising: a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the substrate region, wherein the first magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first orthogonal axis, wherein a center of the first magnetic field sensing element is disposed along the first orthogonal axis; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the substrate region, wherein the second magnetic field sensing element comprises an axis of maximum sensitivity substantially perpendicular to the axis of maximum sensitivity of the first magnetic field sensing element and substantially parallel to the first surface of the semiconductor substrate, wherein a center of the second magnetic field sensing element is disposed along the second orthogonal axis; and an electronic circuit disposed upon the substrate, coupled to the first and second magnetic field sensing elements (404, 406) and configured to sum first and second signals from the first and second magnetic field sensing elements (404, 406) to generate a combined signal, and configured to compare the combined signal with a reference signal to generate a two-state signal having a change of state when the ferromagnetic object moves closer to the semiconductor substrate than a predetermined distance.