Abstract: A motion and proximity sensitive system for monitoring spatial relationship between mobile objects comprising two way communication between a Child Unit, affixed to the child, and a Parent Unit, carried by the parent or guardian, is disclosed. When the Child Unit senses motion and determines that it is beyond a set near field proximity to the Parent Unit, the Child Unit communicates alerts to the Parent Unit allowing the parent to trigger an alarm on the Child Unit. A second alarm function selected by the mode switch sounds an alarm automatically in response to motion beyond the set near field proximity according to an adaptive alarm sequence.

Abstract: A motion sensitive theft detector system for portable articles featuring two way communication between the theft detector unit installed in or affixed to the portable article and the control unit carried by the owner. The theft detector communicates alerts to the control unit allowing the user to screen for false alarms and to trigger an alarm at the portable article when warranted. A timing based alert suppression algorithm allows the system to be carried in its armed state without creating frequently repeated alerts at the control unit. A second alarm function selected by the mode switch sounds an alarm automatically in response to motion according to an adaptive alarm sequence. The adaptive alarm varies the alarm in response to frequency and duration of motion so that isolated movement triggers a warning but persistent motion triggers a full scale alarm.

Abstract: A motion sensitive theft detector system for portable articles featuring two way communication between the theft detector unit installed in or affixed to the portable article and the control unit carried by the owner. The theft detector communicates alerts to the control unit allowing the user to screen for false alarms and to trigger an alarm at the portable article when warranted. A second alarm function selected by the mode switch sounds an alarm automatically in response to motion according to an adaptive alarm sequence. The adaptive alarm varies the alarm in response to frequency and duration of motion so that isolated movement triggers a warning but persistent motion triggers a full scale alarm.

Abstract: A method of and apparatus for determining very accurately the position of a device inside biological tissue comprising a detecting instrument with a probe, which probe generates a small magnetic field which can be disturbed by a magnetically permeable metal in the device inside the tissue when a narrow end of the probe is positioned immediately adjacent to tissue containing the metal, whereby after the metal-carrying device is inserted in the tissue, the end of the probe is used to precisely locate the device by scanning the tissue until the magnetic field is disturbed which causes the instrument to emit a signal.

Abstract: A circuit for determining very accurately the position of a device inside biological tissue in which a probe generates a small magnetic field which can be disturbed by a magnetically permeable metal in the device inside the tissue when a narrow end of the probe is positioned immediately adjacent to tissue containing the metal, whereby after the metal-carrying device is inserted in the tissue, the end of the probe is used to precisely locate the device by scanning the tissue until the magnetic field is disturbed, which disturbance causes the circuit to generate a signal.

Abstract: This device enables apartment dwellers to communicate with and thereby identify persons desiring ingress to an apartment building through a controlled access vestibule. The convenience and security of a conventional intercom is provided by this device, but without substations and their associated dedicated wiring. Communication is initiated via residential telephones which effect a ringing signal (to be sent) from the central telephone office to the device. This device automatically answers the incoming call on the line, transmits an audible signal in the preferred embodiment, enables voice communication, and disconnects.