Acoustic occupancy sensor

• US 20070182581A1
• Filed: 02/06/2006
• Published: 08/09/2007
• Est. Priority Date: 02/06/2006
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Cooper Technologies Company (Eaton Corporation PLC.)
• Inventors: Elwell, Brian
• Granted Patent: US 7,777,632 B2
• Time in Patent Office: Days
• US Class Current: 340/825.360
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/523 for presence detection burglar, theft or intruder alarms G08B13/00, e.g. G08B13/16
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An acoustic occupancy sensor.

Claims

1. An occupancy sensor, comprising:

an acoustic transmitter;

an acoustic receiver;

a variable bandpass filter operably coupled to the acoustic receiver; and

a controller operably coupled to the acoustic transmitter, the acoustic receiver, and the variable bandpass filter;

wherein the controller is adapted to;

transmit acoustic signals using the acoustic transmitter,

receive acoustic signals using the acoustic receiver,

filter the acoustic signals using the variable bandpass filter, and

process the filtered acoustic signals to determine the presence or absence of an occupant within a defined region.

2. An occupancy sensor, comprising:

an acoustic transmitter;

an acoustic receiver comprising;

an acoustic sensor;

a pre-amplifier operably coupled to the acoustic sensor comprising a digital potentiometer, wherein the digital potentiometer is adapted to control the gain of the pre-amplifier to prevent clipping of signals received by the acoustic receiver; and

an analog to digital converter operably coupled to the pre-amplifier;

a demodulator operably coupled to the acoustic receiver;

a variable bandpass filter operably coupled to the demodulator comprising;

a digital potentiometer adapted to control a gain of the bandpass filter;

a digital potentiometer adapted to control a tuning of the bandpass filter; and

a digital potentiometer adapted to control a ratio of a center frequency of the bandpass filter to a bandwidth of the bandpass filter; and

a controller operably coupled to the acoustic transmitter, the acoustic receiver,

the demodulator, and the variable bandpass filter comprising;

a pre-amplifier engine adapted to control the acoustic receiver;

a bandpass filter engine adapted to control the variable bandpass filter;

a doppler shift engine adapted to characterize the signals filtered by the variable bandpass filter; and

an occupancy sensing engine adapted to characterizations of the Doppler shift engine to determine the presence of absence of the occupant within the defined region;

wherein the controller is adapted to;

transmit acoustic signals using the acoustic transmitter,

receive acoustic signals using the acoustic receiver,

process the received acoustic signals using the demodulator,

filter the processed acoustic signals using the variable bandpass filter, and

process the filtered acoustic signals to determine the presence or absence of an occupant within a defined region.

3. The occupancy sensor of claim 2, wherein the bandpass filter engine comprises:

a quiet bandwidth search engine for searching a range of frequencies for quiet bandwidth areas that do not include background noise; and

wherein the doppler shift engine is adapted to characterize the signals filtered by the variable bandpass filter within the quiet bandwidth areas.

4. The occupancy sensor of claim 2, wherein the bandpass filter engine comprises:

a noisy bandwidth search engine for searching a range of frequencies for noisy bandwidth areas that include background noise; and

wherein the doppler shift engine is adapted to characterize the signals filtered by the variable bandpass filter that are not within the noisy bandwidth areas.

5. The occupancy sensor of claim 2, wherein the occupancy sensing engine comprises:

a determination of possible noise engine for processing signals filtered by the variable bandpass filter to determine if they indicate a possible source of noise;

a determination of possible occupancy engine for processing the signals filtered by the variable bandpass filter to determine if they indicate the possible presence of an occupant within the defined region; and

a statistical processing engine for processing the indications of possible noise and occupants to determine if the defined region is occupied by an occupant, wherein the statistical processing engine determines that the defined region is occupied by an occupant based upon the frequency of the indications of occupants within the defined region.

6. The occupancy sensor of claim 2, wherein the occupancy sensing engine comprises:

a determination of noise engine for processing a subset of signals filtered by the variable bandpass filter to determine if they indicate a source of noise; and

a determination of occupancy engine for processing the subset of the signals filtered by the variable bandpass filter to determine the presence or absence of an occupant within the defined region.

7. The occupancy sensor of claim 2, wherein the occupancy sensing engine comprises:

a determination of noise engine for processing the signals filtered by the variable bandpass filter within a predetermined time period to determine if they indicate a source of noise; and

a determination of occupancy engine for processing the signals filtered by the variable bandpass filter within a predetermined time period to determine the presence or absence of an occupant within the defined region.

8. A method of operating an occupancy sensor, comprising:

transmitting acoustic signals into a defined region;

receiving acoustic signals from the defined region;

filtering the received acoustic signals using a variable bandpass filter; and

processing the filtered acoustic signals to determine a presence or absence of an occupant within a defined region.

9. A method of operating an occupancy sensor, comprising:

transmitting acoustic signals into a defined region;

receiving acoustic signals from the defined region;

converting the acoustic signals into electrical signals;

amplifying the electrical signals without clipping the electrical signals;

filtering the received acoustic signals using a variable bandpass filter;

controlling a ratio of a center frequency to a bandwidth of the variable bandpass filter;

sweeping the variable bandpass filter upwardly along a range of frequencies;

then sweeping the variable bandpass filter downwardly along a range of frequencies;

time averaging an amplitude of the filtered acoustic signals;

comparing the time averaged amplitudes of the filtered acoustic signals;

determining if a filtered acoustic signal indicates a source of noise within the defined region; and

determining if a filtered acoustic signal indicates a presence of an occupant within the defined region.

10. The method of claim 9, further comprising:

searching for quiet bandwidth areas within a range of frequencies that do not include background noise; and

time averaging an amplitude of the filtered acoustic signals within the quiet bandwidth areas.

11. The method of claim 9, further comprising:

searching for noisy bandwidth areas within a range of frequencies that include background noise; and

time averaging an amplitude of the filtered acoustic signals not within the noisy bandwidth areas.

12. The method of claim 9, further comprising:

determining a possible presence of a source of noise within the defined region;

determining a possible presence of an occupant within the defined region; and

determining the presence of an occupant within the defined region as a function of a frequency of the determination of the possible presence of an occupant within the defined region.

13. The method of claim 9, further comprising:

determining a possible presence of a source of noise within the defined region;

determining a possible presence of an occupant within the defined region; and

determining the presence of an occupant within the defined region as a function of a frequency of the determination of the possible presence of an occupant within the defined region relative to a frequency of the determination of the possible presence of a source of noise within the defined region.

14. The method of claim 9, further comprising:

time averaging an amplitude of a subset the filtered acoustic signals.

15. The method of claim 9, further comprising:

time averaging an amplitude of the filtered acoustic signals for a finite time period.

16. A system for operating an occupancy sensor, comprising:

means for transmitting acoustic signals into a defined region;

means for receiving acoustic signals from the defined region;

means for filtering the received acoustic signals using a variable bandpass filter; and

means for processing the filtered acoustic signals to determine a presence or absence of an occupant within a defined region.

17. A system for operating an occupancy sensor, comprising:

means for transmitting acoustic signals into a defined region;

means for receiving acoustic signals from the defined region;

means for converting the acoustic signals into electrical signals;

means for amplifying the electrical signals without clipping the electrical signals;

means for filtering the received acoustic signals using a variable bandpass filter;

means for controlling a ratio of a center frequency to a bandwidth of the variable bandpass filter;

means for sweeping the variable bandpass filter upwardly along a range of frequencies;

means for then sweeping the variable bandpass filter downwardly along a range of frequencies;

means for time averaging an amplitude of the filtered acoustic signals;

means for comparing the time averaged amplitudes of the filtered acoustic signals;

means for determining if a filtered acoustic signal indicates a source of noise within the defined region; and

means for determining if a filtered acoustic signal indicates a presence of an occupant within the defined region.

18. The system of claim 17, further comprising:

means for searching for quiet bandwidth areas within a range of frequencies that do not include background noise; and

means for time averaging an amplitude of the filtered acoustic signals within the quiet bandwidth areas.

19. The system of claim 17, further comprising:

means for searching for noisy bandwidth areas within a range of frequencies that include background noise; and

means for time averaging an amplitude of the filtered acoustic signals not within the noisy bandwidth areas.

20. The system of claim 17, further comprising:

means for determining a possible presence of a source of noise within the defined region;

means for determining a possible presence of an occupant within the defined region; and

means for determining the presence of an occupant within the defined region as a function of a frequency of the determination of the possible presence of an occupant within the defined region.

21. The system of claim 17, further comprising:

means for determining a possible presence of a source of noise within the defined region;

means for determining a possible presence of an occupant within the defined region; and

means for determining the presence of an occupant within the defined region as a function of a frequency of the determination of the possible presence of an occupant within the defined region relative to a frequency of the determination of the possible presence of a source of noise within the defined region.

22. The system of claim 17, further comprising:

means for time averaging an amplitude of a subset the filtered acoustic signals.

23. The system of claim 17, further comprising:

means for time averaging an amplitude of the filtered acoustic signals for a finite time period.

24. A computer program for operating an occupancy sensor, comprising program instructions for:

transmitting acoustic signals into a defined region;

receiving acoustic signals from the defined region;

filtering the received acoustic signals using a variable bandpass filter; and

processing the filtered acoustic signals to determine a presence or absence of an occupant within a defined region.

25. A computer program for operating an occupancy sensor, comprising program instructions for:

transmitting acoustic signals into a defined region;

receiving acoustic signals from the defined region;

converting the acoustic signals into electrical signals;

amplifying the electrical signals without clipping the electrical signals;

filtering the received acoustic signals using a variable bandpass filter;

controlling a ratio of a center frequency to a bandwidth of the variable bandpass filter;

sweeping the variable bandpass filter upwardly along a range of frequencies;

then sweeping the variable bandpass filter downwardly along a range of frequencies;

time averaging an amplitude of the filtered acoustic signals;

comparing the time averaged amplitudes of the filtered acoustic signals;

determining if a filtered acoustic signal indicates a source of noise within the defined region; and

determining if a filtered acoustic signal indicates a presence of an occupant within the defined region.

26. The computer program of claim 25, further comprising program instructions for:

searching for quiet bandwidth areas within a range of frequencies that do not include background noise; and

time averaging an amplitude of the filtered acoustic signals within the quiet bandwidth areas.

27. The computer program of claim 25, further comprising program instructions for:

searching for noisy bandwidth areas within a range of frequencies that include background noise; and

time averaging an amplitude of the filtered acoustic signals not within the noisy bandwidth areas.

28. The computer program of claim 25, further comprising program instructions for:

determining a possible presence of a source of noise within the defined region;

determining a possible presence of an occupant within the defined region; and

determining the presence of an occupant within the defined region as a function of a frequency of the determination of the possible presence of an occupant within the defined region.

29. The computer program of claim 25, further comprising program instructions for:

determining a possible presence of a source of noise within the defined region;

determining a possible presence of an occupant within the defined region; and

determining the presence of an occupant within the defined region as a function of a frequency of the determination of the possible presence of an occupant within the defined region relative to a frequency of the determination of the possible presence of a source of noise within the defined region.

30. The computer program of claim 25, further comprising program instructions for:

time averaging an amplitude of a subset the filtered acoustic signals.

31. The computer program of claim 25, further comprising program instructions for:

time averaging an amplitude of the filtered acoustic signals for a finite time period.