Abstract: A bending, and position, sensor is composed of a fiber optic or light wave guide, for attachment to the member which is to be bent, or displaced. Light is injected at one end and detected at the other end. Bending of the fiber results in light loss through a surface strip or band, along one side of the fiber, this loss being detected. The loss of light detection is used to produce indication of bending or displacement. Two or more light guides can be oriented to give indication of direction of bending, or displacement.

Abstract: A liquid level sensor comprises a probe containing closely spaced therein an elongate light emitter and an elongate light collector, the housing of the probe permitting light to issue from the interior from the emitter and to return to the collector. A light transmitting medium fills the probe housing. Means are provided for feeding light to the emitter and from the collector. An indicator can be provided, adapted to provide a level indication obtained form the light fed from the collector.