Methods, systems, and apparatus, for handling applications in an ambient computing system. One of the methods includes determining, by a low-power processing component, that particular sensor signals have a particular property. In response, a machine learning engine performs an inference pass over a machine learning model using the sensor signals to generate a model output. If the model output of the machine learning engine matches an application-specific condition, one or more of the other processing components are activated to execute an particular application corresponding to the application-specific condition.