One type of sensor for measuring the angle of an output shaft (e.g., in an aircraft or an automobile) uses four linear Hall sensors packaged in a single integrated circuit (IC) and a diametrically magnetized disk (i.e., a magnet) oriented above the IC which contains the Hall sensors. The magnet is typically mounted to the output shaft of the servo and the IC is typically mounted on a printed circuit board (PCB) normal to the output shaft axis. To provide redundancy, some IC manufacturers produce ICs with two sets of four Hall sensors (e.g., for a total of eight sensors). However, since both sets of sensors are packaged in the same IC, such sensors are vulnerable to common mode failures (e.g., both sets of Hall sensors are unavailable if the IC loses power). New techniques for measuring the angle of a shaft (e.g., with less vulnerability to common mode failures) would be desirable.