An electronic device, comprising: a radar system, implemented at least partially in hardware, configured to: sense reflections from a user in a radar field; provide an analysis of the reflections from the user; and provide, based on the analysis of the reflections, radar data; and one or more computer-readable media having instructions stored thereon that, responsive to execution by one or more computer processors, implement a persistent radar-based interaction manager configured to: maintain the radar system in an idle mode, the idle mode requiring no more than a first threshold of power; determine, based on a first subset of the radar data, whether a presence of the user is within an awareness zone of the electronic device; responsive to a determination that the user is within the awareness zone, cause the radar system to enter an attention mode, the attention mode requiring no more than a second threshold of power, the second threshold of power greater than the first threshold of power; responsive to an entrance to the attention mode and based on a second subset of the radar data, determine whether the user intends or does not intend to interact with the electronic device; responsive to a determination that the user does not intend to interact with the electronic device, cause the radar system to exit the attention mode and enter the idle mode; and responsive to a determination that the user intends to interact with the electronic device, cause the radar system to exit the attention mode and enter an interaction mode, the interaction mode requiring no more than a third threshold of power, the third threshold of power greater than the second threshold of power. a radar system, implemented at least partially in hardware, configured to: sense reflections from a user in a radar field; provide an analysis of the reflections from the user; and provide, based on the analysis of the reflections, radar data; and sense reflections from a user in a radar field; provide an analysis of the reflections from the user; and provide, based on the analysis of the reflections, radar data; and one or more computer-readable media having instructions stored thereon that, responsive to execution by one or more computer processors, implement a persistent radar-based interaction manager configured to: maintain the radar system in an idle mode, the idle mode requiring no more than a first threshold of power; determine, based on a first subset of the radar data, whether a presence of the user is within an awareness zone of the electronic device; responsive to a determination that the user is within the awareness zone, cause the radar system to enter an attention mode, the attention mode requiring no more than a second threshold of power, the second threshold of power greater than the first threshold of power; responsive to an entrance to the attention mode and based on a second subset of the radar data, determine whether the user intends or does not intend to interact with the electronic device; responsive to a determination that the user does not intend to interact with the electronic device, cause the radar system to exit the attention mode and enter the idle mode; and responsive to a determination that the user intends to interact with the electronic device, cause the radar system to exit the attention mode and enter an interaction mode, the interaction mode requiring no more than a third threshold of power, the third threshold of power greater than the second threshold of power. maintain the radar system in an idle mode, the idle mode requiring no more than a first threshold of power; determine, based on a first subset of the radar data, whether a presence of the user is within an awareness zone of the electronic device; responsive to a determination that the user is within the awareness zone, cause the radar system to enter an attention mode, the attention mode requiring no more than a second threshold of power, the second threshold of power greater than the first threshold of power; responsive to an entrance to the attention mode and based on a second subset of the radar data, determine whether the user intends or does not intend to interact with the electronic device; responsive to a determination that the user does not intend to interact with the electronic device, cause the radar system to exit the attention mode and enter the idle mode; and responsive to a determination that the user intends to interact with the electronic device, cause the radar system to exit the attention mode and enter an interaction mode, the interaction mode requiring no more than a third threshold of power, the third threshold of power greater than the second threshold of power.