Motion detection using pressure sensing

Patent metadata

Field	Value
Publication number	US-9631996-B2
Application number	US-201414323306-A
Country	US
Kind code	B2
Filing date	Jul 3, 2014
Priority date	Jul 3, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

According to an embodiment, a method of sensing motion includes receiving a first signal from a first pressure sensor and a second signal from a second pressure sensor, comparing the first signal and the second signal, and characterizing a motion based on the comparing.

First claim

What is claimed is:

1. A method of sensing motion comprising:
receiving a first signal from a first pressure sensor and a second signal from a second pressure sensor;
comparing the first signal and the second signal; and
characterizing a motion of the first pressure sensor and the second pressure sensor based on the comparing.

2. The method of claim 1 , further comprising low pass filtering the first signal and second signal.

3. The method of claim 2 , wherein low pass filtering comprises passing frequencies below 10 Hz.

4. The method of claim 1 , further comprising:
receiving a third signal from a third pressure sensor; and
comparing the first signal, second signal, and third signal.

5. The method of claim 1 , wherein comparing the first signal and the second signal comprises determining a difference signal between the first signal and the second signal.

6. The method of claim 1 , further comprising:
generating the first signal at a first deflectable membrane and a first sensing structure formed adjacent the first deflectable membrane; and
generating the second signal at a second deflectable membrane and a second sensing structure formed adjacent the second deflectable membrane.

7. The method of claim 6 , further comprising:
receiving pressure waves in a first pressure port coupled to the first membrane and having a length extending away from the first membrane at least three times greater than a longest dimension of the first membrane; and
receiving pressure waves in a second pressure port coupled to the second membrane and having a length extending away from the second membrane at least three times greater than a longest dimension of the second membrane.

8. A motion sensor comprising:
a plurality of pressure sensors, each comprising a membrane having a planar surface with a normal pointing in a different direction, wherein the plurality of pressure sensors are configured to generate pressure signals based on deflections of each membrane; and
a motion detection circuit coupled to the plurality of pressure sensors, wherein the motion detection circuit is configured to:
receive the pressure signals from the plurality of pressure sensors,
compare the pressure signals to each other, and
characterize a motion of the plurality of pressure sensors based on comparing the pressure signals to each other.

9. The motion sensor of claim 8 , wherein the motion detection circuit further comprises a low pass filter configured to low pass filter the pressure signals before comparing the pressure signals to each other.

10. The motion sensor of claim 9 , wherein the low pass filter is configured to pass frequencies below 10 Hz.

11. The motion sensor of claim 8 , wherein the plurality of pressure sensors comprises two pressure sensors.

12. The motion sensor of claim 8 , wherein the plurality of pressure sensors comprises three pressure sensors.

13. The motion sensor of claim 8 , wherein each pressure sensor of the plurality of pressure sensors comprises a sound port having a first length in a direction parallel to the respective normal at least three times longer than a longest dimension of the respective membrane.

14. The motion sensor of claim 13 , wherein at least one sound port is filled with foam.

15. The motion sensor of claim 13 , wherein at least one sound port comprises a guide grid.

16. The motion sensor of claim 13 , wherein the first length of at least one sound port is at least ten times longer than a longest dimension of the respective membrane.

17. The motion sensor of claim 8 , wherein each normal of the plurality of pressure sensors is orthogonal to each other normal of the plurality of pressure sensors.

18. The motion sensor of claim 8 , wherein each pressure sensor of the plurality of pressure sensors comprises one of a group consisting of a static pressure sensor, a dynamic pressure sensor, and a microelectromechanical (MEMS) microphone.

19. A microphone system comprising:
a plurality of microelectromechanical system (MEMS) microphones comprising a plurality of signal outputs, wherein the signal outputs are configured to supply a plurality of pressure signals generated by the plurality of MEMS microphones;
a motion processing circuit coupled to the plurality of signal outputs, wherein the motion processing circuit is configured to characterize motions of the microphone system based on the plurality of pressure signals; and
an audio processing circuit coupled to the plurality of signal outputs, wherein the audio processing circuit is configured to output an electrical audio signal based on the plurality of pressure signals.

20. The microphone system of claim 19 , wherein the motion processing circuit comprises a low pass filter configured to pass frequencies below 10 Hz.

21. The microphone system of claim 20 , wherein the audio processing circuit comprises a high pass filter configured to pass frequencies above 500 Hz.

22. The microphone system of claim 19 , wherein the plurality of MEMS microphones comprises two MEMS microphones.

Assignees

• Infineon Technologies Ag

Inventors

• Wiesbauer Andreas
• Mandl Christian
• Kopetz Andreas
• Helm Roland

Classifications

• H04R2201/003

  Mems transducers or their use · CPC title

• G01L13/025 Primary

  using diaphragms · CPC title

• G01L15/00 Primary

  Devices or apparatus for measuring two or more fluid pressure values simultaneously · CPC title

• H04R23/00

  Transducers other than those covered by groups H04R9/00 - H04R21/00 {(diaphragms for transducers of the distributed-mode type H04R7/045)} · CPC title

• H04R19/04

  Microphones (H04R19/01 takes precedence) · CPC title