Abstract: A seismic sensitive cable and a seismic sensitive ribbon for detecting introducers over long lines has a plurality of miniature geophones each having three conductors extending therefrom, three lines connecting the conductors of the geophones in parallel with one another, an elastic sheath covering the lines and extending in a predetermined direction, a plurality of substantially hard cases each covering a respective one of the miniature geophones, wherein the elastic sheath connects the hard cases with one another.

Abstract: For detecting intruders in long and very narrow perimeter zones two elongated sensitive elements extending in a direction of their elongation and are spaced form one another in a transverse direction so as to define therebetween an alarm zone which is narrower than a detection zone in which the sensitive elements are located, a processing unit is connected with the sensitive elements so as to receive a signal from the respective one of the sensitive element when an intruder crosses the sensitive element, and to process the signals to determine whether an intruder is in the detection zone or in the alarm zone, and an interface is provided operative for outputting an output signal produced by the processing unit as a result of processing of the signals from the sensitive elements.

Abstract: A device for sensing seismic and/or acoustic vibrations, has a body of a particulate material composed of a plurality of individual particles, and a system for determining changes in electrical conductivity of the particulate material caused by seismic and acoustic vibrations.

Abstract: A seismic sensor, has a case, a pre-charged, non-conductive membrane located between two plates that form a capacitor and accommodated inside the case, with one of the plates being immovable relative to the case and the other of the plates being movable relative to the one plate under the action of seismic activity of a medium in which the sensor is located, so that the capacitor produces an electrical signal responsive to the seismic activity, and a mass increasing element associated with the movable plate so as to increase mass of the movable plate and therefore enhance oscillations of the movable plate under the action of the seismic activity.

Abstract: A seismic sensor, comprising a case, a pre-charged, non-conductive membrane located between two plates that form a capacitor and accommodated inside the case, with one of the plates being immovable relative to the case and the other of the plates being movable relative to the one plate under the action of seismic activity so that the capacitor produces an electrical signal responsive to the seismic activity of a medium in which the sensor is located, and a mass increasing element associated with the movable plate so as to increase mass of the movable plate and therefore to enhance oscillations of the movable plate under the action of the seismic activity, the mass increasing element being formed as a further case which is connected to the movable plate and is located in condition of equilibrium in an inoperative position of the sensor.

Abstract: A system for protection from intruders has at least two groups of sensors arranged so that the sensors in each of the groups are spaced from one another in a predetermined direction, while the groups of the sensors are spaced from one another in another direction which is substantially transverse to the one direction, the sensors being formed as seismic sensors, a single central control and processing unit arranged to receive unprocessed signals from the seismic sensors, at least one external alarm generating unit including a loudspeaker and a search light, at least one television camera associated with the alarm generating unit, and at least one phone line associated with the control and processing unit, the sensors, the alarm generating unit and the central control and processing unit being connected so that when an intruder is detected by at least one of the sensors of one of the groups of sensors, the alarm generating unit generates a loud voice warning by the loud speaker and generates a light by the sea

Abstract: A seismic sensor, has a case, a pre-charged, non-conductive membrane located between two plates that form a capacitor and accommodated inside the case, with one of the plates being immovable relative to the case and the other of the plates being movable relative to the one plate under the action of seismic activity of a medium in which the sensor is located, so that the capacitor produces an electrical signal responsive to the seismic activity, and a mass increasing element associated with the movable plate so as to increase mass of the movable plate and therefore enhance oscillations of the movable plate under the action of the seismic activity.

Abstract: A seismic sensor, comprising a case, a pre-charged, non-conductive membrane located between two plates that form a capacitor and accommodated inside the case, with one of the plates being immovable relative to the case and the other of the plates being movable relative to the one plate under the action of seismic activity so that the capacitor produces an electrical signal responsive to the seismic activity of a medium in which the sensor is located, and a mass increasing element associated with the movable plate so as to increase mass of the movable plate and therefore to enhance oscillations of the movable plate under the action of the seismic activity, the mass increasing element being formed as a further case which is connected to the movable plate and is located in condition of equilibrium in an inoperative position of the sensor.

Abstract: A system for detecting of an intruder has a plurality of groups of sensors connected in parallel with one another, the sensors being selected from the group consisting of seismic sensors, acoustic sensors and both, a plurality of individual processing units each connected with a respective one of the groups of sensors, the individual processing units being connected in parallel with one another, a central processing unit connected with all the parallel-connected processing units so that each of the individual processing units can obtain information about a presence of an intruder near any of the groups of sensors, and means for obtaining a visual image of the intruder near any of the groups of sensors and transmitting the image to the central processing unit.

Abstract: A device for sensing seismic and/or acoustic vibrations, has a body of a particulate material composed of a plurality of individual particles, and a system for determining changes in electrical conductivity of the particulate material caused by seismic and acoustic vibrations.

Abstract: A tornado detection system has a plurality of sensors each having a body of a particulate material composed of a plurality of individual particles; and means for determining changes in electrical conductivity of the particulate material caused by seismic and acoustic vibrations; and means for connecting the sensors with one another so as to form a zone sensitive to movement of a tornado.

Abstract: A device for sensing seismic and/or acoustic vibrations, has a body of a particulate material composed of a plurality of individual particles, and a system for determining changes in electrical conductivity of the particulate material caused by seismic and acoustic vibrations.