Methods and Apparatus for Security Device Portal Sensing

• US 20080143526A1
• Filed: 12/13/2007
• Published: 06/19/2008
• Est. Priority Date: 12/16/2006
• Status: Active Grant

• Current Assignee: Roc2Trac, Inc.
• Original Assignee: Quixcode, LLC
• Inventors: Spenik, John, Woodbury, Brian, Lastinger, Roc
• Granted Patent: US 7,663,483 B2
• Time in Patent Office: Days
• US Class Current: 340/547
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other

Abstract

A security device, according to various aspects of the present invention, detects movement of a provided portal cover. The security device includes a sensor, a bias magnet, and a processor. The sensor provides indicia of a magnitude of a magnetic flux through the sensor. The bias magnet provides the magnetic flux through the sensor. The processor detects a change in the magnitude of the magnetic flux outside an upper boundary and a lower boundary of a first threshold and a second threshold respectively. The sensor does not move with respect to the magnet. Movement between the sensor and the portal cover changes the magnitude of the magnetic flux through the sensor. The processor determines an average value of a series of values of the indicia of the magnitude of the magnetic flux that fall within the upper boundary and the lower boundary of the first threshold. The upper boundary and the lower boundary of the first threshold and the second threshold respectively are set in accordance with the average value.

Claims

1. A security device that detects movement of a provided portal cover, the security device comprising:

a sensor that provides indicia of a magnitude of a magnetic flux through the sensor;

a bias magnet that provides the magnetic flux through the sensor;

a processor that detects a change in the magnitude of the magnetic flux outside an upper boundary and a lower boundary of a first threshold and a second threshold respectively;

wherein;

the sensor does not move with respect to the magnet;

movement between the sensor and the portal cover changes the magnitude of the magnetic flux through the sensor;

the processor determines an average value of a series of values of the indicia of the magnitude of the magnetic flux that fall within the upper boundary and the lower boundary of the first threshold;

the upper boundary and the lower boundary of the first threshold and the second threshold respectively are set in accordance with the average value.

2. The security device of claim 1 wherein the processor provides a notice in accordance with the change in the magnitude of the magnetic flux that falls outside the upper boundary and the lower boundary of the second threshold.

3. The security device of claim 1 wherein:

the sensor comprises a sensing axis; and

the bias magnet provides the magnetic flux parallel to the sensing axis.

4. The security device of claim 1 wherein the average value comprises only the indicia of the magnitude that fall between the lower boundary and the upper boundary of the first threshold.

5. The security device of claim 1 wherein the indicia comprises a voltage.

6. The security device of claim 1 wherein the indicia comprises a current.

7. The security device of claim 1 wherein the sensor couples to the security device and is positioned adjacent to the portal cover.

8. The security device of claim 1 wherein the magnet couples to the security device distal from the portal cover along an axis between the sensor and the magnet.

9. The security device of claim 1 wherein the absolute value of the upper boundary and the lower boundary of the first threshold and the second threshold respectively are different.

10. The security device of claim 1 wherein the absolute value of the upper boundary and the lower boundary of the first threshold are less than the absolute value of the upper boundary and the lower boundary of the second threshold.

11. The security device of claim 1 wherein the series of values comprises at least one thousand values.

12. The security device of claim 1 wherein the processor receives indicia of the magnitude at least every 0.5 seconds.

13. The security device of claim 1 wherein the processor comprises an analog-to-digital converter that converts a voltage.

14. A method performed by a security device for detecting movement of a portal cover, the method comprising:

averaging a series of values of indicia of a magnitude of a magnetic flux through a sensor that fall within an upper and a lower boundary of a first threshold to provide an average value;

detecting indicia the magnitude of the magnetic flux that falls outside an upper and a lower boundary of a second threshold;

adjusting the upper and the lower boundary of the first threshold and the second threshold respectively in accordance with the average value;

providing a signal in accordance with detecting;

wherein;

a magnet couples to a body of the security device to provide the magnetic flux through the sensor;

the sensor couples to the body;

the sensor does not move with respect to the magnet;

movement of the sensor with respect to the portal cover changes the magnitude of the magnetic flux through the sensor.

15. The method of claim 14 wherein averaging comprises detecting whether a current indicia of the magnitude of the magnetic flux is less than the upper boundary and greater than the lower boundary of the first threshold.

16. The method of claim 14 wherein averaging comprises eliminating each indicia that falls outside the upper boundary and the lower boundary of the first threshold.

17. The method of claim 14 wherein averaging comprises eliminating each indicia that falls outside the upper boundary and the lower boundary of the second threshold.

18. The method of claim 14 wherein adjusting comprises changing a value of the upper boundary and the lower boundary of the first threshold in accordance with a change in the average value.

19. The method of claim 14 wherein adjusting comprises changing a value of the upper boundary and the lower boundary of the second threshold in accordance with a change in the average value.

20. The method of claim 14 wherein the absolute value of the upper boundary and the lower boundary of the first threshold are less than the absolute value of the upper boundary and the lower boundary of the second threshold.