It doesn't require a WiFi device to work.

> If you’d like to prevent your pet’s movement from causing motion notifications, you can exclude pet motion in your WiFi Motion settings by turning on the Exclude Small Pets feature. > Motion is detected based on the amount of signal disruption taking place between the Xfinity Gateway and your selected WiFi-connected devices, so motion from small pets (around 40 pounds or less) can be filtered out while keeping you notified of large movements more likely to be caused by humans.