Patent ID: 6400267
Filing Date: 2002-06-04
Classification: G05B,H01H

Abstract:
A reed switch-based burglar alarm, comprising:a parallelepiped enclosure having top and bottom sides separated with front, back, left and right sides which are perpendicular to said top and bottom sides, said bottom side adapted for mounting to a mounting surface, said enclosure containing burglar alarm circuitry comprising: a first reed switch which lies in a first plane parallel to the plane of said bottom side such that said first reed switch is actuated by a magnet which lies in a plane parallel to said first plane, a second reed switch which lies in a second plane perpendicular to said first plane such that said second reed switch is actuated by a magnet which lies in a plane parallel to said second plane, and monitoring circuitry arranged to monitor the actuation states of said reed switches and to produce an output signal which indicates when the actuation state of one of said reed switches changes, and a magnet mounted to a movable structure adjacent to said alarm enclosure, said first and second reed switches and said magnet arranged such that when said movable structure is a swing-out door and said enclosure's bottom side is mounted to a surface which lies in a plane parallel to the plane in which said swing out door lies when closed, said magnet actuates said first reed switch when said door is closed, and such that when said movable structure is a roll-up door and said enclosure's bottom side is mounted to a surface which lies in a plane perpendicular to the plane in which said roll-up door lies when closed, said magnet actuates said second reed switch when said door is closed.