PIR sensor is the short form of passive Infrared sensor. The main ideology is to provide security. This is based on PIR sensor with an IC that produces siren or buzzer sound. The PIR sensor detects the IR radiation which is emitted from the humans and then it produces a digital output. Mostly it is used in motion detectors, security alarms, and automatic lighting applications. In general they detect movement i.e. changes the amount of infrared radiation. In turn this digital output is given to the Arduino Uno. after getting digital signal from the PIR sensor, the Arduino UNO then triggers the siren. Thus it produces the sound when only human is detected
