Magnetic field sensing device for compassing and switching

• US 20070089311A1
• Filed: 10/26/2005
• Published: 04/26/2007
• Est. Priority Date: 10/26/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Wan, Hong, Witcraft, William, Amundson, Mark
• Granted Patent: US 7,637,024 B2
• Time in Patent Office: Days
• US Class Current: 33/355.R
• CPC Class Codes: G01C 17/28 Electromagnetic compasses with north seeking magnetic elements and having electric pick-offs G01C17/26
• CPC Class Codes: G01C 17/30 Earth-inductor compasses
• CPC Class Codes: H04M 1/0245 using open/close detection
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

A magnetic field sensing device can be realized by using a magnetic sensor in electronic compassing as well as switching. A magnet can be brought in close proximity to the magnetic sensor within an electronic compass to generate a signal that a portable information device has been closed. This signal can be input to a processor or other circuitry to initiate a response to the portable information device being closed. When the magnet is moved out of close proximity to the magnetic sensor, the magnetic sensor can be used in the electronic compass. Thus, a magnetic sensor can serve two functions, namely compassing and switching, reducing the need for separate sensors to perform both functions.

Claims

10. A portable information device comprising:

a first portion having a magnet; and

a second portion having at least one magnetic sensor, wherein the at least one magnetic sensor is used as an electronic compass and the at least one magnetic sensor detects a presence of the magnet, and wherein the detection of the presence of the magnet by the at least one magnetic sensor functions as a switch.

1. A portable information device comprising:

a magnet located at a first portion of the portable information device; and

an electronic compass located at a second portion of the portable information device, the electronic compass comprising at least one magnetic sensor, the at least one magnetic sensor also being used to detect a presence of the magnet.

2. The portable information device of claim 1, wherein the second portion is moveable with respect to the first portion.

3. The portable information device of claim 1, wherein the electronic compass comprises a first axis magnetic sensor and a second axis magnetic sensor.

4. The electronic compass of claim 3, wherein the first magnetic sensor is an x-axis sensor and the second magnetic sensor is a y-axis sensor.

5. The portable information device of claim 1, wherein the electronic compass comprises a first axis magnetic sensor, a second axis magnetic sensor and a third axis magnetic sensor.

6. The electronic compass of claim 5, wherein the first magnetic sensor is an x-axis sensor, the second magnetic sensor is a y-axis sensor and the third magnetic sensor is a z-axis sensor.

7. The portable information device of claim 1, further comprising a processor operable to receive a signal from the electronic compass to determine a compass direction.

8. The portable information device of claim 1, further comprising a processor operable to receive a signal from the at least one magnetic sensor when the presence of the magnet is detected by the at least one magnetic sensor.

9. The portable information device of claim 1, further comprising at least one comparator operable to receive a signal from the at least one magnetic sensor when the presence of the magnet is detected by the at least one magnetic sensor, whereby the comparator digitizes a voltage signal from the at least one magnetic sensor.

11. The portable information device of claim 10, wherein the second portion is moveable with respect to the first portion.

12. The portable information device of claim 10, wherein the electronic compass comprises a first axis magnetic sensor and a second axis magnetic sensor.

13. The electronic compass of claim 12, wherein the first axis magnetic sensor is an x-axis sensor and the second axis magnetic sensor is a y-axis sensor.

14. The portable information device of claim 10, wherein the electronic compass comprises a first axis magnetic sensor, a second axis magnetic sensor, and a third axis magnetic sensor.

15. The electronic compass of claim 14, wherein the first axis magnetic sensor is an x-axis sensor, the second axis magnetic sensor is a y-axis sensor, and the third axis magnetic sensor is a z-axis sensor.

16. The portable information device of claim 10, further comprising a processor operable to receive a signal from the electronic compass to determine a compass direction.

17. The portable information device of claim 10, wherein the switch connects and removes power to circuits contained by the portable information device.

22. The method of claim 18, wherein the portable information device is a cell phone, wherein the first and second portions are selected from a keypad panel and a display panel, and wherein the switching function includes removing power from a display on the display panel.

18. A method for compassing and switching in a portable information device, comprising:

receiving a first signal from a magnetic sensor when the magnetic sensor is within a first distance from a permanent magnet, wherein the first signal is associated primarily with a field strength of the permanent magnet, wherein the magnetic sensor is located at a first portion of the portable information device, wherein the permanent magnet is located at a second portion of the portable information device, and wherein the first and second portions are movable with respect to one another.

receiving a second signal from the magnetic sensor when the magnetic sensor is further than the first distance from the permanent magnet, wherein the second signal is associated primarily with a field strength of the earth;

determining a compass heading from the second signal; and

upon receiving the first signal, performing a switching function.

19. The method of claim 18, wherein the first signal is in a first range of magnetic field strengths detectable by the magnetic sensor;

the second signal is in a second range of magnetic field strengths detectable by the magnetic sensor; and

the second range is greater than the first range.

20. The method of claim 18, wherein the magnetic sensor is a two-axis magnetic sensor.

21. The method of claim 18, wherein the magnetic sensor is a three-axis magnetic sensor.

22-1. The method of claim 17, wherein the portable information device is a GPS receiver, wherein the first and second portions are selected from a cover panel and a display panel, and wherein the switching function includes removing power from a display on the display panel.