What Is Ultrasound Motion Detection?
Some Echo devices can detect motion in a room with ultrasound technology.
Occupancy Routines, and some Alexa features, rely on motion detection to determine whether a room is occupied. When you turn on an Occupancy Routine or feature, some Echo devices emit ultrasound, and use the device microphones to detect motion near the device. Alexa interprets such motion to mean that someone might be in the room.
Motion detection is designed to detect major motion such as walking around the room. It might not detect minor motion, such as waving your hand, or sitting still and reading. A routine also can start when no occupancy is detected, for example, to turn off lights when the room is empty.
Ultrasound motion detection is available on Echo (4th Gen. or newer) and Echo Dot (4th Gen. or newer) devices. The devices don't emit ultrasound until you turn on a feature that uses motion detection, such as Occupancy Routines. Humans can't hear or perceive ultrasound.
