An angular motion detector, of particular relevance in breakaway point detection, includes a flywheel (1) rotatably mounted on a spindle (2). The flywheel (1) is provided with one or more indicia (7), which are detectable by a sensor (8) situated on the object whose angular motion is to be analysed. The sensor (8) is connected to a microprocessor (9). In use the flywheel (1) is rotated manually about the spindle (2) so that the regular detection of the indicia (7) by the sensor (8) causes a train of pulses to be sent to the microprocessor (9). Angular movement of the object, and consequently of the sensor (8), causes a disruption of the pulse train which can be analysed to provide information relating to the time of first movement and the magnitude of the angle moved.