PIR sensors are used to sense movement of people, animals, or other objects. They are commonly used in burglar alarms and automatically-activated lighting systems. They are commonly called simply "PIR", or sometimes "PID", for "passive infrared detector". These sensors can be used with microcontroller boards like Arduino.
Operating voltage is 3-15V and the detection range is 4m.
This product works the same way as this one. Only difference is the size.