Automatic magnetic flow recording device

An automatic magnetic flow recording device, wherein the automatic magnetic flow recording device comprises:

• a plurality of coaxially disposed magnets, each of the magnets having one magnetization direction, and each of the magnets having a wheel shape, wherein the plurality of coaxially disposed magnets form a plurality of coaxially disposed hard magnetic rotating wheels,
• wherein each of the hard magnetic rotating wheels has a cylindrical shape with a center axis and a side surface, a circular cross section in a plane perpendicular to the center axis, and a circumference, has one magnetization direction parallel to a diameter, and has a predetermined turning ratio with respect to other ones of the hard magnetic rotating wheels;
• wherein each of the hard magnetic rotating wheels has at least one corresponding biaxial magnetoresistive angle sensor in the plane of the circular cross section,
• wherein the biaxial magnetoresistive angle sensor is configured to measure angular positions of the corresponding hard magnetic rotating wheel throughout a range of 0-360 degrees of rotation for the corresponding hard magnetic rotating wheel;
• wherein the biaxial magnetoresistive angle sensor comprises at least one substrate, each substrate defining an X-Y plane where the X-Y plane has an X-axis direction and a Y-axis direction perpendicular to the X-axis direction and further defining a Z-axis direction perpendicular to the X-Y plane and extending away from the substrate, wherein the biaxial magnetoresistive angle sensor includes at least two uniaxial linear magnetoresistive sensors, wherein the at least two uniaxial linear magnetoresistive sensors include at least one Z-axis magnetoresistive sensor configured to sense in the Z-axis direction,
• wherein the biaxial magnetoresistive angle sensor is positioned in the plane and beyond the side surface of the cylindrical shape of the corresponding hard magnetic rotating wheel such that a distance from the center axis to the side surface is less than a distance from the center axis to the biaxial magnetoresistive sensor, wherein the substrate is arranged to provide the X-axis direction tangential to the circumference of the hard magnetic rotating wheel and the Z-axis magnetoresistive sensor is a single-axis linear magnetoresistive sensor arranged to provide the Z-axis direction radial to the hard magnetic rotating wheel.