Abstract: A seismic and pressure wave sensor adapted to be buried in the earth to detect disturbances comprises a deformable tube containing an incompressible liquid in which a force-responsive transducer is immersed. The output of the transducer is an alternating signal having spectral components corresponding to both seismic (10-100 Hz) and pressure (< 1 Hz) type earth vibrations produced by human footsteps remote from and near to the buried sensor. In order to provide perimeter protection, an even-numbered plurality of such sensors are arranged in a row along a single curved or straight line and are electrically connected in parallel with the polarities of successive transducers reversed. A single processor connected to the outputs of such plurality of sensors has frequency-separated band-limited channels for isolating and detecting seismic and pressure signals, respectively, and for audibly, visually or otherwise indicating the pressure of either or both signals.

Abstract: A force sensor comprising an array of three conductive points respectively insulated from one another; a movable conductive element normally resting in contact with the points and thus producing an electrical interconnection therebetween and displaceable out of contact with at least one of the points in response to the application of a predetermined force to the sensor; means for connecting the three points to logic circuitry for sensing the interruption of the electrical interconnection and determining in response thereto whether an alarm condition exists; a housing containing the three point array and the movable conductive elements and having an outer configuration which includes a spherical portion; means fixedly mountable onto an article and defining a socket surface complementary to the spherical portion; and clamp means for selectably attaching the housing to the mounting means and permitting ready adjustment of the orientation of the spherical portion with respect to the complementary socket portion w

Abstract: A sensing means is connected to the input of an electronic circuit for triggering a signalling means. The electronic circuit includes a continuous differential amplifier whose two inputs (-) and (+) are connected to the terminals of the sensing means. The input terminals are also connected by means of at least two switches to voltage sources in such a way that, by closing one of the switches, the polarity of the input terminal in question is reversed, to disable the detection device, and, by closing the other switch means, there is an increase, with the same sign, in the polarity of the input in question, for triggering the signalling means.

Abstract: A burglar deterrent switch for installation in a conventional manual switch box for controlling room lights. An electronic sound responsive timing switch illuminates the room lights for a selected period of time in response to the occurrence of a sound and then turns the lights off for another selected period of time. The timing switch has a triac which is shunted across the manual light switch. The gate of the triac is controlled by an SCR connected in a bridge rectifier for controlling the triac gate current. The gate of the SCR is connected to the output of an amplifier and is switched on by sound incident upon a sound transducer connected to the input of the amplifier. A timing circuit means is also connected across the SCR and comprises a pair of voltage reference diodes connected parallel to a capacitance for fixing the voltage to which the capacitance may charge and having a resistance series connected to the parallel diodes and capacitance.

Abstract: An alarm system for a vehicle or trailer, the system comprising an alarm circuit which is energizable after a predetermined time period responsively to actuation of a control circuit of the system, and switch means for controlling the operating state of the control circuit.

Abstract: An intrusion alarm and emergency illumination apparatus includes an audible alarm and lighting device which are activated by sounds associated with human intrusion into a physical structure. The sounds of intrusion may be differentiated from other sounds by a bandpass digital amplifier and rate of rise detector which receive audio-electrical waveforms from a microphone. A monostable multivibrator and variable resistance element may be employed to select the duration of activation of the lightning device and alarm and may be employed to provide a preselected exit delay permitting an operator to arm the system and leave the premises without having the sounds of his exiting activate the lighting device and alarm. Emergency illumination may be provided by a reserve power system used to energize the lighting device and alarm system during power outages.