The Focus72 allows you to select between two different motion detection methods: Motion Detection: When selecting this method motion is triggered based on a certain percentage of pixel change. The percentage varies according to the sensitivity level you set in the app. The lower you set the level, the higher the number of pixels that need to alter before an event is detected and recorded. PIR-based Motion Detection: In this case motion is detected by means of a PIR sensor, a passive infrared sensor. This sensor detects emitted infrared energy from objects (humans and animals, but also cars) in the form of heat. In general differences of around 5-10º Celsius compared with the ambient temperature in the field of view and within a 10m /30ft range of the camera are detected. Which option is best very much depends on what you are using the camera for and where the camera is pointed at.