A water softener salt monitoring system includes a brine tank configured for retaining a quantity of salt, a quantity of water and having a bottom, a sensor secured to the brine tank and constructed and arranged for sending a signal to the bottom, the sensor including a receiver configured for receiving a reflected signal off of at least one of the quantity of salt, the quantity of water and the bottom, and a controller connected to the sensor and programmed to compare the reflected signals with preset values, and for generating an alarm signal upon receipt of deviations from the preset values.

A method for monitoring an oil level in a machine includes transmitting a light beam into an optical system to be reflected or refracted to a receiver to generate a reception signal. The light beam is emitted at a set transmission power, and an oil deficiency is recognized when the reception signal exceeds a predefined level value. The transmission power of the light beam is settable between a minimum and a maximum transmission power, and contamination of the optical system is analyzed by: (a) the transmitter transmits a first light beam at the maximum transmission power to generate a first reception signal, and (b) analyzing the difference between the first reception signal and a second reception signal generated by a light beam at less than the maximum transmission power, the magnitude of the difference representing a measure of the degree of contamination of the optical system.

A detecting apparatus includes a container, and a detecting device including a transmitting module and a receiving module. The transmitting module includes a light-emitting element provided at a first point of the container and operable to transmit a photo signal to propagate toward the container along an optical path. The receiving module includes a light-receiving element provided at a second point of the container and configured to receive the photo signal transmitted through the container. The receiving module is operable to determine whether a substance is present within the container based on receipt of the photo signal. An imaginary tangent plane tangent to the first point is not parallel to an imaginary tangent plane tangent to the second point.

A liquid cartridge includes a first surface, a second surface spaced apart from the first surface, and a third surface extending between the first surface and the second surface, with a liquid outlet through the first surface. A circuit board is mounted on the third surface. A locking mechanism includes a locking surface that extends above the third surface, and a liquid detection mechanism includes a light access portion. The light access portion is disposed between the circuit board and the locking surface, and the circuit board is disposed between the first surface and the light access portion.

An image forming apparatus includes a container to accommodate a developer, and a sensor to output an output signal depending on an amount of the developer in the container, wherein the sensor includes a light emitting element and a light receiving element which are provided outside the container, and a light guide provided on a wall surface of the container and configured to guide light, emitted by the light emitting element, toward the light receiving element through an inside space of the container. The light guide also includes projected portions configured such that light travels from outside of the container to the inside of the container in a direction intersecting with the direction of gravity.

Heating device for domestic appliances comprising a base, a coil resistor extending from said base, and an optical sensor able to determine the level of washing liquid around said coil resistor.

A liquid level sensing system provides a removable reservoir incorporating a reflective surface that can be interrogated by a stationary optical sensor in a receptacle receiving the removable reservoir. The optical sensor may detect the presence of the liquid within the reservoir without connection to the reservoir simplifying the process of making the reservoir removable while still allowing sensing of its contents. By aligning the optical axis with the insertion axis of the reservoir sensitive optical alignment problems are minimized.

Aircraft fuel tank, which has a visual control system inside the tank, includes at least a side wall (12), an upper wall (14) and a lower wall (16), the tank (10) comprising a visual inspection system (22) inside the tank (10). The visual inspection system (22) includes an inspection eyepiece (24) arranged in one of the walls (12, 14, 16), a light inlet (26) arranged in one of the walls (12, 14, 16) and configured to allow light from an artificial light source (30) situated outside the tank (10) to enter the tank (10), and a light guide (28) protruding inside the tank (10) from the light inlet (26) to guide the light produced by the artificial light source (30) to the inside of the tank (10).

A liquid cartridge includes a first surface, a second surface spaced apart from the first surface, and a third surface extending between the first surface and the second surface, with a liquid outlet through the first surface. A circuit board is mounted on the third surface. A locking mechanism includes a locking surface that extends above the third surface, and a liquid detection mechanism includes a light access portion. The light access portion is disposed between the circuit board and the locking surface, and the circuit board is disposed between the first surface and the light access portion.

A valve for dosing and mixing two fluids includes two respective inlet ducts, a double chamber for controlling the flows, at least one actuator configured to regulate the flow rates of the two fluids to be mixed, an electronic control unit and a Brix degrees optical sensor, arranged on the mixing duct of the mixture of the two fluids and operatively connected to the electronic control unit. The optical sensor is configured to send a measurement and control signal to the electronic control unit to drive the actuator so as to proportionally control the flow rates of the two fluids and, therefore, regulate the mixing ratio of the two fluids.