Wireless reed switch-based burglar alarm

• US 6,400,267 B1
• Filed: 06/22/2001
• Issued: 06/04/2002
• Est. Priority Date: 01/05/2001
• Status: Expired due to Fees

• Current Assignee: Calstar Systems Group, Inc.
• Original Assignee: Calstar Systems Group, Inc.
• Inventors: Carner, Douglas, Gordon-Levitt, Daniel D.
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): Nguyen, Phung
• Application Number:
  US09/888,012
• Time in Patent Office: 347 Days
• Field of Search: 340/547, 340/545.6, 340/545.8, 340/551, 340/545.7, 200/61.41, 200/61.76, 200/81.9, 200/61.71, 335/205, 335/207
• US Class Current: 340/547
• CPC Class Codes: G05B 19/0423 Input/output
• CPC Class Codes: G05B 2219/23051 Remote control, enter program remote, detachable programmer
• CPC Class Codes: G05B 2219/24024 Safety, surveillance
• CPC Class Codes: G05B 2219/25187 Transmission of signals, medium, ultrasonic, radio
• CPC Class Codes: G05B 2219/25459 Reed relay separation
• CPC Class Codes: H01H 36/0046 Limit switches, also fail-safe operation or anti-tamper considerations

Abstract

A reed switch-based burglar alarm features two reed switches mounted perpendicularly to each other within the alarm enclosure. The orientations of the perpendicular reed switches permit the enclosure to be mounted in alternate ways with respect to a movable structure being monitored. The first reed switch lies in a plane parallel to the surface to which the alarm is mounted, and the second reed switch lies in a plane perpendicular to the mounting surface. Thus, a magnet can be mounted on a swing-out type door and the enclosure mounted on a wall adjacent to the door such that the magnet actuates the first reed switch when the door is closed. Similarly, a magnet can be mounted on a roll-up type door and the enclosure mounted to a surface perpendicular to the door such that the magnet actuates the second reed switch when the door is closed. The alarm preferably includes features which enable it to be mounted on the outside of the space being protected. An anti-tamper reed switch can be employed to detect the presence of a rogue magnet, and another anti-tamper switch can be used to indicate that the cover of the enclosure has been removed. The preferred alarm communicates wirelessly, and is housed in an impact and weather resistant enclosure.

Claims

1. 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.

2. The burglar alarm of claim 1, wherein said monitoring circuitry is arranged to wirelessly broadcast said output signal to a remote receiver.

3. The burglar alarm of claim 1, wherein said circuit board is mounted to one of said front, back, left and right sides.

4. The burglar alarm of claim 3, further comprising a second circuit board mounted to one of said top and bottom sides which contains at least a portion of said burglar alarm circuitry.

5. The burglar alarm of claim 3, wherein said circuit board mounted to one of said front, back, left and right sides contains all of said burglar alarm circuitry.

6. The burglar alarm of claim 1, further comprising an anti-tamper reed switch positioned such that it may be actuated by a rogue magnet brought near said enclosure, said monitoring circuitry arranged to produce an output signal which indicates when said anti-tamper reed switch has been actuated.

7. The burglar alarm of claim 1, wherein said enclosure includes a removable lid which provides access to said burglar alarm circuitry, said burglar alarm further comprising an anti-tamper switch arranged such that its actuation state changes when said lid is removed from said enclosure, said monitoring circuitry arranged to produce an output signal which indicates when said anti-tamper switch'"'"'s actuation state has changed.

8. The burglar alarm of claim 1, wherein said enclosure is weather-resistant.

9. A wireless, reed switch-based burglar alarm suitable for use on the outside of an area being protected by said alarm, comprising:

a movable structure having open and closed states which blocks access to a protected area when closed, said movable structure lying in a first plane when closed,

an enclosure having a bottom side mounted to a mounting surface on the outside of said protected area, said enclosure containing burglar alarm circuitry comprising;

a first reed switch oriented in a second 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 second plane,

a second reed switch oriented in a third plane perpendicular to said second plane such that said second reed switch is actuated by a magnet which lies in a plane parallel to said third plane,

an anti-tamper reed switch positioned such that it may be actuated by a rogue magnet brought near said enclosure,

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 first and second reed switches changes and an output signal which indicates when said anti-tamper reed switch has been actuated, and

broadcasting circuitry arranged to wirelessly broadcast said output signals to a remote receiver, and

a magnet mounted on said movable structure,

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.

10. The burglar alarm of claim 9, wherein said enclosure includes a removable lid which provides access to said burglar alarm circuitry, said burglar alarm further comprising a second anti-tamper switch arranged such that its actuation state changes when said lid is removed from said enclosure, said monitoring circuitry arranged to produce an output signal which indicates when said second anti-tamper switch'"'"'s actuation state has changed.

11. The burglar alarm of claim 10, wherein said anti-tamper switch includes a spring which is compressed and actuates said anti-tamper switch when said lid is attached to said enclosure and which is de-compressed and de-actuates said anti-tamper switches when said lid is removed.

12. The burglar alarm of claim 9, wherein said enclosure is weather-resistant.

13. The burglar alarm of claim 9, wherein said enclosure comprises a parallelepiped 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 first and second reed switches attached to a circuit board mounted such that said first reed switch lies in a plane parallel to said bottom side and said second reed switch lies in a plane perpendicular to said bottom side.

14. The burglar alarm of claim 13, wherein said circuit board is mounted to one of said front, back, left and right sides.

15. The burglar alarm of claim 14, further comprising a second circuit board mounted to said bottom side which contains at least a portion of said burglar alarm circuitry.

16. The burglar alarm of claim 14, wherein said circuit board mounted to one of said front, back, left and right sides contains all of said burglar alarm circuitry.

17. The burglar alarm of claim 14, further comprising a second circuit board mounted to said top side which contains at least a portion of said burglar alarm circuitry.