CUE supports SDKs for iOS, Android, Python, Debian, and Linux.
Ultrasonic audio files can be generated in the CUE Client Portal or transmitted dynamically using CUE's iOS or Android SDK. When audio is generated in the portal, you can attach an associated JSON payload to the audio file, which a receiving device can fetch if a data connection is available.
We have high-reliability transmissions of 25 bits per second.
Range varies according to speaker quality and volume. From a mobile phone, an expected range should be a few centimeters to ten meters. From larger speakers, distances of several hundred meters are achievable.
Distance is related to volume. It is possible to programmatically increase the system volume on Android but not iOS. The user must manually adjust their volume on iOS.
It is possible to run CUE in the background of an iOS or Android application. That being said, we generally recommend staying to foreground-only applications as many users are skeptical of the microphone being activated in the background.
Since CUE's engine is provided as a native iOS and Android framework, it is compatible with any cross-platform tool that allows execution of native code. This includes React Native.
It's possible to approximate distance using the returned power parameter in the engine callback. Since there are a number of variables, including the local environment and the power of the transmitting speaker, there is no easy "distance formula" that works in all cases. That being said, if you know the power of the transmitting device, it is possible to approximate distance from the speaker with a reasonable resolution (0.5 - 2 meters) using CUE.