An improved transparency sensor (10) uses Brewster's Law to detect the presence of sheets of transparency material (20). The sensor (10) includes a light emitting diode (LED) (12) and two photodiodes (14, 16) arranged to receive light reflected from the material (20). The LED (12) supplies incident light at an angle (.theta.) which is related to the refractive index of the transparency material (20) to be detected. A polarizing filter (18) is associated with one of the photodetectors (16) and is...

Semiconductor gas sensors with improved selectivity to target gases are provided by having a semiconductor gas-sensing layer and a layer thereon of microporous ceramic oxide having catalytic activity.

A gas sensor of the type having a housing defining a chamber within which light is transmitted from a source to a detector through an optical path, includes internal mirror portions having part ellipsoidal shape. Light is transmitted from a source to a detector via the reflective portions. The detector is arranged to sense light only from a limited range of angles, such that only light transmitted through a defined optical path reflected off the two reflective portions from the source reaches th...

A deflection sensor for a taut wire perimeter fence detection system, which can be installed after the fence wire has been installed easily, and the sensor the operates in line with the wire tension. The sensor includes a plate member adapted to be pivotally mounted, a first wire attachment point at one end of said plate member, a second wire attachment point remote from said first wire attachment point and a transducer or sensor element located on said plate member between the attachment points...

Disclosed are humidity sensor structures, and fabrication techniques, which result in uniform and reliable humidity sensing, reliable electrical connections in small sensors, and simplified and inexpensive manufacture.

Disclosed are humidity sensor structures, and fabrication techniques, which result in uniform and reliable humidity sensing, reliable electrical connections in small sensors, and simplified and inexpensive manufacture.

Platinum resistance thermometers with means for preventing ingress of moisture from the atmosphere at temperatures below 100.degree.C., and preferably below 150.degree.C., and for relieving the rise in pressure within the thermometer as the thermometer is heated. In one arrangement the thermometer has a metal sheath sealed apart from a vent and a closure member is provided on the free end of a bimetallic strip. In another arrangement, the closure member is carried on the end of a tube mounted wi...

A rotatable insulating disc carries a closed grid of conductors over one part of one side and a similar but open grid over another part. An oscillator is coupled to a coil which is parallel to the disc and produces a cyclically varying but symmetrical field through the disc. Two pairs of pick-up coils sense, for respective orthogonal directions, the distortion of the field by the closed grid and detector circuits coupled to the pick-up coils provide signals representing the sine and cosine of th...

The invention is a deceleration-responsive sensor particularly adaptable for use with vehicle safety devices of the type comprising an inflatable air bag which inflates at the moment of impact to protect passengers. The sensor comprises a movable inertia mass responsive to deceleration forces acting over a wide range of direction. The inertia mass is biased to an initial position to avoid undesired continued small motion activation. The inertia mass and its mounting is constructed to have a natu...

A mechanism disposed within the hub of an aircraft control wheel including pitch and roll flexure devices which act as the primary restraints to loads applied to the control wheel and a plurality of load beams that function as redundant sensors which react to a minimal percentage of the applied load. Bearing surfaces between the pitch and roll flexure devices effectively isolate the pitch flexures and beams from the load flexures and beams thereby eliminating cross-coupling between these devices...