Voice trigger components - just-ai/aimybox-android-sdk GitHub Wiki
The user has to activate your voice assistant before speaking with it. It could be a tap on the microphone button or any other way to wake the assistant.
One of the most popular way is to wake an assistant with special wake word like "Okay Google". In this case the voice assistant listens for this word or phrase continuously in the background and once the user speaks it - the voice assistant starts to listen the voice command.
Aimybox provides a collection of ready to use wake word detector implementations: