How does the motion detection of a Smart Camera or Video Doorbell work?

Smart devices with a camera can be classified into two types, each with its own method of motion detection: 

Battery-powered devices:

These cameras are equipped with a PIR sensor (passive infrared sensor) that detects motion based on changes in infrared radiation. The sensitivity of the PIR sensor can be set to three different levels, with settings varying for indoor and outdoor cameras:

Outdoor cameras:
- Low: Detects motion up to a distance of 6 meters
- Medium: Detects motion up to a distance of 8 meters
- High: Detects motion up to a distance of 10 meters

Indoor cameras:
- Low: Detects motion up to a distance of 4 meters
- Medium: Detects motion up to a distance of 6 meters
- High: Detects motion up to a distance of 8 meters

Devices powered by a power adapter:

These cameras use image analysis to detect motion. They analyze changes in the image and determine whether there is motion based on a percentage difference. The sensitivity can be set in three levels:

- Low: Moving object should fill 45% of the image
- Medium: Moving object should fill 35% of the image
- High: Moving object should fill 25% of the image

In addition, these cameras can set a specific frame within the image so that only motion within this area is detected. This makes detection more accurate and prevents unnecessary notifications outside the desired detection area.