Power management using a low-power radar

Techniques and apparatuses are described that enable power management using a low-power radar. The described techniques enable a radar system to reduce overall power consumption, thereby facilitating incorporation and utilization of the radar system within power-limited devices. In one aspect, the radar system can replace other power-hungry sensors and provide improved performance in the presence of different environmental conditions, such as low lighting, motion, or overlapping targets. In another aspect, the radar system can cause other components within the electronic device to switch to an off-state based on detected activity in an external environment. By actively switching the components between an on-state or the off-state, the radar system enables the computing device to respond to changes in the external environment without the use of an automatic shut-off timer or a physical touch or verbal command from a user.