Occupancy tracking using sound recognition

1. An occupancy tracking device, comprising:

a network interface operably coupled to a Heating, Ventilation, and Air Conditioning (HVAC) system, wherein the HVAC system is configured to control a temperature of a space;

a plurality of microphones configured to capture sound samples;

a memory operable to store a voice data log comprising a plurality of entries, wherein each entry comprises:

a timestamp that identifies when a sound sample was recorded;

an audio signature that describes characteristics of the sound sample, wherein the audio signature comprises a numerical value that uniquely identifies characteristics of an audio signal; and

a direction of arrival for the sound sample, wherein the direction of arrival identifies a direction for a source for the sound sample; and

a processor operably coupled to the network interface, the plurality of microphones, and the memory, configured to:

receive a plurality of sound samples over a predetermine time period;

compute an audio signature for each sound sample from the plurality of sound samples;

determine a direction of arrival for each sound sample from the plurality of sound samples;

populate entries in the voice data log for the plurality of sound samples, wherein populating the entries in the voice data log comprises associating each sound sample with a timestamp, an audio signature, and a direction of arrival;

identify one or more clusters for the populated entries based on an audio signature that is associated with the populated entries, wherein each cluster comprises audio signatures that are associated with a voice of a person;

determine a number of clusters that are identified;

determine a predicted occupancy level based on the number of clusters that are identified, wherein the predicted occupancy level is equal to the number of clusters that are identified; and

control the HVAC system based on the predicted occupancy level.

2. The device of claim 1 , wherein the processor is further configured to:

identify entries in the voice data log that are associated with a sound sample that does not contain a voice signal; and

remove the identified entries that are associated with a sound sample that does not contain a voice signal from the voice data log.

3. The device of claim 1 , wherein the process is further configured to:

identify a plurality of clusters that are associated with the same direction of arrival; and

remove the plurality of clusters that are associated with the same direction of arrival before determining the number of clusters.

4. The device of claim 1 , wherein computing an audio signature comprises:

identifying an audio signal that is present within a sound sample;

identifying characteristics of the audio signal; and

generating a numeric value based on the identified characteristics of the audio signal.

5. The device of claim 1 , wherein controlling the HVAC system comprises:

determining a number of people that are present within the space is greater than zero; and

transitioning the HVAC system out of a low power mode.

6. The device of claim 1 , wherein controlling the HVAC system comprises:

determining a number of people that are present within the space is zero; and

transitioning the HVAC system to a low power mode.

7. The device of claim 1 , wherein controlling the HVAC system comprises adjusting a set point temperature for the space.

8. An occupancy tracking method, comprising:

receiving a plurality of sound samples over a predetermine time period;

computing an audio signature for each sound sample from the plurality of sound samples, wherein the audio signature comprises a numerical value that uniquely identifies characteristics of an audio signal;

determining a direction of arrival for each sound sample from the plurality of sound samples, wherein the direction of arrival identifies a direction for a source for the sound sample;

populating entries in a voice data log for the plurality of sound samples, wherein each entry comprises:

a timestamp that identifies when a sound sample was recorded;

an audio signature that describes characteristics of the sound sample; and

a direction of arrival for the sound sample;

identifying one or more clusters for the populated entries based on an audio signature that is associated with the populated entries, wherein each cluster comprises audio signatures that are associated with a voice of a person;

determining a number of clusters that are identified;

determining a predicted occupancy level based on the number of clusters that are identified, wherein the predicted occupancy level is equal to the number of clusters that are identified; and

controlling a Heating, Ventilation, and Air Conditioning (HVAC) system based on the predicted occupancy level, wherein the HVAC system is configured to control a temperature of a space.

9. The method of claim 8 , further comprising:

identifying entries in the voice data log that are associated with a sound sample that does not contain a voice signal; and

removing the identified entries that are associated with a sound sample that does not contain a voice signal from the voice data log.

10. The method of claim 8 , further comprising:

identifying a plurality of clusters that are associated with the same direction of arrival; and

removing the plurality of clusters that are associated with the same direction of arrival before determining the number of clusters.

11. The method of claim 8 , wherein computing an audio signature comprises:

identifying an audio signal that is present within a sound sample;

identifying characteristics of the audio signal; and

generating a numeric value based on the identified characteristics of the audio signal.

12. The method of claim 8 , wherein controlling the HVAC system comprises:

determining a number of people that are present within the space is greater than zero; and

transitioning the HVAC system out of a low power mode.

13. The method of claim 8 , wherein controlling the HVAC system comprises:

determining a number of people that are present within the space is zero; and

transitioning the HVAC system to a low power mode.

14. The method of claim 8 , wherein controlling the HVAC system comprises adjusting a set point temperature for the space.

15. An occupancy tracking system, comprising:

a Heating, Ventilation, and Air Conditioning (HVAC) system, wherein the HVAC system is configured to control a temperature of a space; and

a thermostat in signal communication with the HVAC system, configured to:

receive a plurality of sound samples over a predetermine time period;

compute an audio signature for each sound sample from the plurality of sound samples, wherein the audio signature comprises a numerical value that uniquely identifies characteristics of an audio signal;

determine a direction of arrival for each sound sample from the plurality of sound samples, wherein the direction of arrival identifies a direction for a source for the sound sample;

populate entries in a voice data log for the plurality of sound samples, wherein each entry comprises:

a timestamp that identifies when a sound sample was recorded;

an audio signature that describes characteristics of the sound sample; and

a direction of arrival for the sound sample;

identify one or more clusters for the populated entries based on an audio signature that is associated with the populated entries, wherein each cluster comprises audio signatures that are associated with a voice of a person;

determine a number of clusters that are identified;

determine a predicted occupancy level based on the number of clusters that are identified, wherein the predicted occupancy level is equal to the number of clusters that are identified; and

control the HVAC system based on the predicted occupancy level.

16. The system of claim 15 , wherein the thermostat is further configured to:

identify entries in the voice data log that are associated with a sound sample that does not contain a voice signal; and

remove the identified entries that are associated with a sound sample that does not contain a voice signal from the voice data log.

17. The system of claim 15 , wherein the thermostat is further configured to:

identify a plurality of clusters that are associated with the same direction of arrival; and

remove the plurality of clusters that are associated with the same direction of arrival before determining the number of clusters.

18. The system of claim 15 , wherein computing an audio signature comprises:

identifying an audio signal that is present within a sound sample;

identifying characteristics of the audio signal; and

generating a numeric value based on the identified characteristics of the audio signal.

19. The system of claim 15 , wherein controlling the HVAC system comprises:

determining a number of people that are present within the space is greater than zero; and

transitioning the HVAC system out of a low power mode.

20. The system of claim 15 , wherein controlling the HVAC system comprises adjusting a set point temperature for the space.