Abstract: An underwater ocean bottom cable constructed of a series of axially aligned cable segments alternately arranged with sensor units. The sensor units include an outer housing with an interior cavity in which a sensor module is suspended by a cradle. Vanes on the sensor module protrude through axially elongated openings in the outer housing to dig into the seabed to provide good seismic coupling between the seabed and pressure sensors and motion sensors housed in the sensor module. The outer sensor housing is split into complementary portions that clamp firmly onto the ends of adjacent cable segments. Stress members, such as high modulus fiber ropes, extend out the ends of adjacent cable segments. Axial channels formed in the intervening outer sensor housing on opposite sides of the sensor module receive the stress members, which, along with the cradle, provide seismic isolation between the cable segments and the sensor modules.

Abstract: An underwater ocean bottom cable constructed of a series of axially aligned cable segments alternately arranged with sensor units. The sensor units include an outer housing with an interior cavity in which a sensor module is suspended by a cradle. Vanes on the sensor module protrude through axially elongated openings in the outer housing to dig into the seabed to provide good seismic coupling between the seabed and pressure sensors and motion sensors housed in the sensor module. The outer sensor housing is split into complementary portions that clamp firmly onto the ends of adjacent cable segments. Stress members, such as high modulus fiber ropes, extend out the ends of adjacent cable segments. Axial channels formed in the intervening outer sensor housing on opposite sides of the sensor module receive the stress members, which, along with the cradle, provide seismic isolation between the cable segments and the sensor modules.

Abstract: A highly sensitive silicon micro-machined sensor package is provided for use in a micro-g environment that can also resist high shock in excess of 5000 g. The sensor is provided to measure acceleration in cooperation with associated electronics which are required to have electrical contact with sensor elements. The sensor is sealed in a high vacuum environment, and is arranged and designed to be free of temperature induced stress to the sensor. The sensor die package assembly comprises a silicon micro-machined sensor die, a ceramic package, two contact springs, a shorting clip, solder preform, a metal lid and a getter foil for ensuring a good vacuum for an extended period. The sensor die comprises a moving mass with eight supporting flexures on both sides of the proof mass. The proof mass's movement is protected on both sides by a top and a bottom cap. Acceleration applied to the package and the die causes the proof mass to move vertically in relation with the adjacent caps.

Abstract: Apparatus for measuring a characteristic of motion and methods for its manufacture are disclosed in which a sensor structure includes a support structure, and a mass suspended from such support structure by a spring connecting arrangement and electrical devices for measuring displacement of the mass which results from a force applied to the support structure. An apparatus is provided where the mechanical spring constant of the connecting arrangement of the sensor structure is provided to be a high value representative of a strong, stiff spring which resists breaking due to high forces applied to it, and where an electric spring constant is provided to yield a small effective sensor spring constant K.sub.eff =K.sub.m -K.sub.e. Methods are also provided to manufacturing the apparatus by specifying the mechanical spring constant and providing an electric spring constant which will yield a desired effective spring constant which produces a desired characteristic of the sensor structure.

Abstract: A sensor structure (10) has a central mass (16) mounted within a support structure comprising an outer frame (18) with upper and lower covers (12, 14). Eight L-shaped or elbow-shaped ribbon springs are fit about the corners (28) of the mass (16) to allow mass (16) for movement from a reference position with respect to the support structure. One leg of each spring is connected to the middle of an associated side (26A) of the mass (16) while the other leg is connected to the outer frame (18). According to an alternative embodiment, each of the springs (72) is characterized by a relatively larger width at spring-mass connection point (74) and at spring-support connection point (73) and a relatively smaller width at an elbow-bend region between connection points.

Abstract: A sensor structure (10) has a central mass (16) mounted within a support structure comprising an outer support frame (18), and upper and lower plates or covers (12, 14). Eight L-shaped ribbon springs (32, 34) fit about the corners (28) of the mass (16) to mount mass (16) for movement from a reference position with respect to the support structure. One leg (38) of each spring (32, 34) is connected to an associated side (26A) of the mass (16) centrally of the length of the associated side (26A). The other leg (40) is connected to the outer support frame (18). The sensor structure is designed for use as a sensing mechanism in an electrostatic accelerometer arrangement.

Abstract: An improved device for monitoring the presence of a person, animal or piece of property within a predefined space. The invention consists of a means for attaching to a monitoree, a transmitter assembly containing electronic circuitry which periodically sends a coded signal a limited distance to a remote detection unit. If the expected signal is not received, indicating that the person or object has been removed from the predefined space, an alarm condition is indicated. The transmitter is securely attached to the item being monitored by means of a non-stretchable, flexible, circuit strap which indicates an alarm condition when the strap is tampered with. The strap is locked into the transmitter assembly by a latch key which also triggers the transmitter to begin sending signals. The device is easily reattached or transferred to another item to be monitored by monitoring personnel by removing the latch key and inserting a new latch key after the device has been reinstalled.

Abstract: A transducer fabricated by micro-machining includes E-shaped leaf springs suspending a mass from a support. The transducer is formed by chemical etching through openings of opposite faces of a silicon wafer on which etch stop layer patterns are diffused. Sense and force conductive patterns are diffused onto opposite faces of the suspended mass. The legs of the E-shaped leaf springs are formed of a composite of a polysilicon base layer, a silicon dioxide insulating layer and a gold conducting layer. The thickness of such layers are selected to minimize bowing effects of the spring legs due to materials of different coefficients of thermal expansion. The spring-mass-support structure is sandwiched between opposite plates having corresponding force and conductive patterns which face such patterns on the suspended mass.