Determining location/orientation of an audio device

1. A first apparatus, comprising:

a transmitter configured to transmit a first signal having a first frequency to a second apparatus;

a first receiver configured to receive, from the second apparatus, a second signal having a second frequency responsive to the first signal; and

a processor configured to:

determine a latency associated with the transmitted first signal and received second signal; and

determine a distance between the first apparatus and the second apparatus based, at least in part, on the determined latencies.

2. The first apparatus of claim 1 , wherein determining the distance comprises:

determining a total travel time of the first signal and the second signal based, at least in part, on the determined latencies.

3. The first apparatus of claim 2 , further comprising:

a timer,

wherein the processor is further configured to:

start the timer after transmitting the first signal;

stop the timer after receiving the second signal; and

determine the total travel time based, at least in part, on an elapsed time between starting and stopping of the timer.

4. The first apparatus of claim 3 , wherein the processor is configured to:

determine a time of flight by subtracting the determined latencies from the total travel time and dividing the difference by two.

5. The first apparatus of claim 4 , wherein the distance is determined based, at least in part, on the speed of sound and the determined time of flight.

6. The first apparatus of claim 4 , wherein the latency associated with the transmitted first signal comprises a preconfigured delay time at the second apparatus.

7. The first apparatus of claim 1 , wherein receiving the second signal comprises:

receiving a sound wave with a frequency varying in time.

8. The first apparatus of claim 7 , wherein the latency associated with the received second signal at the first apparatus is determined based, at least in part, on a rate of change of frequency of the second signal.

9. The first apparatus of claim 1 , further comprising:

a second receiver configured to receive the second signal; and

a third receiver configured to receive the second signal,

wherein the processor is configured to determine a direction of the second apparatus relative to the first apparatus based, at least in part, on a difference in arrival times of the second signal at each of the first, second, and third receivers.

10. The first apparatus of claim 9 , wherein determining the direction is further based on a distance between the first and second receivers and a distance between the second and third receivers.

11. The first apparatus of claim 1 , wherein at least one of the first signal or the second signal comprises an ultrasonic signal.

12. The first apparatus of claim 1 , wherein at least one of the first frequency or the second frequency comprises a frequency greater than or equal to 8 kHz.

13. A second apparatus, comprising a processor and memory comprising instructions which, when executed by the processor, cause the second apparatus to:

receive, from a first apparatus, a first signal having a first frequency;

determine a latency associated with receiving the first signal;

calculate when to transmit a second signal having a second frequency based on the determined latency; and

transmit the second signal based on the calculation.

14. The second apparatus of claim 13 , wherein:

the first signal comprises a signal with a frequency varying in time.

15. The second apparatus of claim 13 , wherein determining the latency comprises:

determining a delay in time of an arrival of the first signal at the second apparatus based, at least in part, on a rate of change of frequency of the first signal.

16. The second apparatus of claim 13 , wherein calculating when to transmit the second signal comprises:

subtracting the determined latency from a preconfigured delay time.

17. The second apparatus of claim 13 , wherein at least one of the first frequency or the second frequency comprises a frequency greater than or equal to 8 kHz.

18. A method for communication by a first apparatus, comprising:

transmitting a first signal to a second apparatus;

receiving a second signal from the second apparatus, responsive to the first signal, at each of a first, second, and third microphones at the first apparatus; and

determining a distance between the first and second apparatus based, at least in part, on a latency associated with the first, transmitted signal and a latency associated with the second, received signal.

19. The method of claim 18 , further comprising:

determining a time of flight for the second signal to reach each of the first, second, and third microphones; and

determining a direction of the second apparatus relative to the first apparatus based, at least in part, on: a distance between the first and second microphone, a distance between the second and third microphone, and the determined time of flights.

20. The method of claim 18 , wherein the latency associated with the second, received signal at the first apparatus is determined based, at least in part, on a rate of change of frequency of the second signal.