SENSOR FOR SENSING ACCELERATIONS

• US 20100010771A1
• Filed: 05/25/2007
• Published: 01/14/2010
• Est. Priority Date: 06/21/2006
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Ikkink, Teunis, Boeve, Hans
• Granted Patent: US 8,862,422 B2
• Time in Patent Office: Days
• US Class Current: 702/141
• CPC Class Codes: G01P 15/0891 with indication of predetermined acceleration values G01P15/135 takes precedence
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G11B 19/043 by detecting a free-fall condition

Abstract

Sensors (1) for sensing accelerations are provided with accelerometers (11) for measuring accelerations, with magnetometers (12) for measuring magnetic fields, and with processors (13) for, in response to acceleration measurements and magnetic field measurements, judging the accelerations. The processors (13) may comprise acceleration units (14) for comparing acceleration signals with acceleration thresholds, and magnetic field units (15) for comparing changes of magnetic field signals per time interval with rate thresholds. The processors (13) may further comprise decision units (17) for, in response to comparison results from the acceleration units (14) and the magnetic field units (15), deciding whether a total acceleration forms part of a tumbling free-fall or a non-tumbling free-fall or not. The processors (13) may yet further comprise distinguishing units (18) and control units (19). Devices (2) may comprise sensors (1).

Claims

1. A sensor for sensing accelerations, which sensor comprises:

an accelerometer for measuring an acceleration,

a magnetometer for measuring a magnetic field, and

a processor for, in response to at least one acceleration measurement and at least one magnetic field measurement, judging the acceleration.

2. The sensor according to claim 1, the accelerometer comprising an at least two dimensional accelerometer for measuring the acceleration in at least two dimensions and for generating at least two acceleration signals per acceleration measurement.

3. The sensor (1) according to claim 1, the magnetometer comprising an at least two dimensional magnetometer for measuring the magnetic field in at least two dimensions and for generating at least two magnetic field signals per magnetic field measurement.

4. The sensor according to claim 1, the processor comprising:

an acceleration unit for comparing at least one acceleration signal with at least one acceleration threshold, and

a magnetic field unit for comparing at least one change of at least one magnetic field signal per time interval with at least one rate threshold.

5. The sensor (1) according to claim 4, the processor further comprising:

a decision unit for, in response to comparison results from the acceleration unit and the magnetic field unit, deciding whether a total acceleration forms part of a tumbling free-fall or a non-tumbling free-fall or not.

6. The sensor according to claim 4, the processor further comprising:

a distinguishing unit for, in response to comparison results from the acceleration unit and the magnetic field unit, distinguishing a first acceleration in a first direction from a second acceleration in a second direction, and

a decision unit for, in response to comparison results from the acceleration unit and the magnetic field unit A, deciding whether at least one of the first and second accelerations forms part of a tumbling free-fall or a non-tumbling free-fall.

7. The sensor according to claim 4, the processor further comprising:

a control unit for, in response to at least one comparison result from the acceleration unit and/or the magnetic field unit, controlling a clock signal generator for generating a variable clock signal defining a variable bandwidth rate and/or a variable sampling rate.

8. A device comprising the sensor according to claim 1, the acceleration being the acceleration of the device.

9. A method for sensing accelerations, which method comprises the steps of:

measuring an acceleration,

measuring a magnetic field, and

in response to at least one acceleration measurement and at least one magnetic field measurement, judging the acceleration.

10. A computer program product for performing the steps of the method according to the claim 9.

11. A medium for storing and comprising the computer program product according to the claim 10.