Abstract: A connector-engagement-state detection system for detecting states of engagement of a connector with a connector receiver and for detecting one or more fault states within the detection system itself so as to prevent false engagement state information. In some embodiments, the detection system includes a light source that emits detection light and a light sensor that detects the detection light. The connector-receiver and/or connector are configured, and the light source and the light sensor are located relative to one another so that some of the detection light reaches the sensor regardless of whether or not the connector is fully engaged with the connector-receiver. This arrangement allows for the determination of one or more faults within the detection system itself, such as a faulty light source or faulty detector.

Abstract: An apparatus and method for measuring the torque of a rotating shaft wherein two gears are placed adjacent to each other on the shaft but are fixed to the shaft at a predetermined distance apart such that the twist in the shaft causes an angular displacement of one of the gears with respect to the other. Each gear is provided with a number of teeth equally spaced thereon, one such gear having a different number of teeth than the other gear and a unique tooth to act as a reference point thus establishing a vernier relationship between the two gears. A single sensing means is positioned at the interface between the adjacent gears and detects the amount of overlap for each pair of gear teeth (one from each gear) as they rotate thereby. Each pair of teeth will be in a different degree of alignment with one such pair being in nearest alignment. As the torque twists the shaft, the location of the pair of teeth in nearest alignment will move circumferentially around the interface between the gears.