DESCRIPTION

PIR "Passive Infrared"sensors allow you to sense motion, almost always used to detect whether a human has moved in or out of the sensors range

How to Use PIR Sensor

The PIR sensor have 3 pins:

Power:    3-5 VDC

Output:   High (when motion detected)

          Low (no motion detected)

Ground:  connected to ground

The output pin will go "high" to 3.3V and light up the LED when motion detected.

Specifications:

Input Voltage:         DC 3-5V

Output signal:         3.3V (motion detected-output high)

Detection Angle:       110 degree

Detection Angle:       max 7 m

How Does The PIR Sensor Work

The PIR sensor itself has two slots each one of them is made of a special material that is sensitive to infrared. When a warm body like a human or animal passes by, it first intercepts one half of the PIR sensor. This causes a positive differential change between the two halfes. These change pulses are what is detected.