Abstract: Because GPS does not work indoors, mobile electronics devices that use GPS for activities do not work inside a building. An embodiment of the present invention uses ultrasonic tone generators in each room. The ultrasonic tone generators can be built into cameras or separate devices. Each device may emit a unique tone that has a high enough frequency that most people cannot hear the frequency or combination of frequencies. Using a built-in microphone on a mobile device, the incoming audio may be analyzed in the frequency domain to determine the loudest tone above the human hearing threshold. This tone may be mapped to a specific room that can then be sent to the mobile electronics device to perform any location-aware actions.

Abstract: Because GPS does not work indoors, mobile electronics devices that use GPS for activities do not work inside a building. An embodiment of the present invention is uses ultrasonic tone generators in each room. The ultrasonic tone generators can be built into cameras or separate devices. Each device may emit a unique tone that has a high enough frequency that most people cannot hear the frequency or combination of frequencies. Using a built-in microphone on a mobile device, the incoming audio may be analyzed in the frequency domain to determine the loudest tone above the human hearing threshold. This tone may be mapped to a specific room that can then be sent to the mobile electronics device to perform any location-aware actions.