Turn Presence Detection Off or On
Press the Microphones & Camera Enable/Disable 
button on your Echo device, or use the Alexa app to turn off Presence Detection.
Echo devices with Presence Detection capabilities use ultrasound, and sometimes, ultrasound combined with Wi-Fi signals to detect that someone is present. The devices only emit ultrasound when a feature that uses motion detection is enabled, whether by default or your own action.
To turn off Presence Detection without disabling features that rely on Presence Detection, press the Microphones & Camera Enable/Disable button on your Echo device. Press the Microphones & Camera Enable/Disable button on your Echo device again to enable Presence Detection capability.
Note: If you turn off Presence Detection on the device, features that use Presence Detection don't function as intended.
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