An assembly oriented in an x, y, z Cartesian coordinate system with an x axis, a y axis and a z axis, comprising: a base structure, wherein x, y, z Cartesian coordinate system does not move relative to the base structure; a rotatable structure moveably disposed with respect to the base structure, wherein the rotatable structure and the base structure are operable to move in a relative movement along a line relative to each other in a direction tangential to the y axis, wherein the rotatable structure is operable to rotate about a rotation axis parallel to the z axis; first magnet (104; 1502; 2602) fixedly coupled to the base structure, the first magnet (104; 1502; 2602) having north and south poles aligned along a first line stationary with respect to the base structure, the first magnet (104; 1502; 2602) for generating a first magnetic field; a second magnet (112; 904; 1504; 2604) fixedly coupled to the rotatable structure, the second magnet (112; 904; 1504; 2604) having north and south poles aligned along a second line rotatable with the rotatable structure, the second magnet (112; 904; 1504; 2604) for generating a second magnetic field; a magnetic field sensor (110; 1506; 1516; 3000; 3100; 3200; 3300; 3400; 7110; 2606) disposed proximate to the base structure and proximate to the rotatable structure, wherein the magnetic field sensor (110; 1506; 1516; 3000; 3100; 3200; 3300; 3400; 7110; 2606) comprises: at least one magnetic field sensing element for generating at least one sensing element signal responsive to the first and second magnetic fields at a position of the at least one magnetic field sensing element, the at least one sensing element signal indicative of at least one predetermined combination of the relative movement along the line and the rotation about the rotation axis. a base structure, wherein x, y, z Cartesian coordinate system does not move relative to the base structure; a rotatable structure moveably disposed with respect to the base structure, wherein the rotatable structure and the base structure are operable to move in a relative movement along a line relative to each other in a direction tangential to the y axis, wherein the rotatable structure is operable to rotate about a rotation axis parallel to the z axis; first magnet (104; 1502; 2602) fixedly coupled to the base structure, the first magnet (104; 1502; 2602) having north and south poles aligned along a first line stationary with respect to the base structure, the first magnet (104; 1502; 2602) for generating a first magnetic field; a second magnet (112; 904; 1504; 2604) fixedly coupled to the rotatable structure, the second magnet (112; 904; 1504; 2604) having north and south poles aligned along a second line rotatable with the rotatable structure, the second magnet (112; 904; 1504; 2604) for generating a second magnetic field; a magnetic field sensor (110; 1506; 1516; 3000; 3100; 3200; 3300; 3400; 7110; 2606) disposed proximate to the base structure and proximate to the rotatable structure, wherein the magnetic field sensor (110; 1506; 1516; 3000; 3100; 3200; 3300; 3400; 7110; 2606) comprises: at least one magnetic field sensing element for generating at least one sensing element signal responsive to the first and second magnetic fields at a position of the at least one magnetic field sensing element, the at least one sensing element signal indicative of at least one predetermined combination of the relative movement along the line and the rotation about the rotation axis.