The modern world is filled with gadgets that get excited when they sense human motion. Automatic doors in elevators and shopping malls, burglar alarms at houses and shops, automatic lighting systems, electronic amenities in washrooms are just a few examples where human presence or absence puts the device into active or passive state.  Smart, right? Now, what if we tell you that behind this smart response to motion is a gizmo that does not even reach the 2cm mark in size. Known as Pyroelectric or Passive Infrared Sensor (PIR, in both cases), this small electronic device is the curious case for this Insight.How does PIR sensor selectively responds to human radiated IRs? Upto what range can this sensor work? What lies inside this sensor that makes it work? This and answers to more questions in this Insight on PIR sensors. What adds more charm to this Insight is that the Panasonic 10m sensor taken is also one of the smallest PIR sensors commercially available till date.  

This tutorial will teach you how to make the simplest motion detecting staircase light without any need of any additional microcontroller and programming using PIR based Sensor. Passive Infrared (PIR) Sensors basically measure the Infrared light radiated by an object present in its field. All living creatures (and objects) with a temperature above absolute zero (which is 0 Kelvin or -273oC) emit heat energy in form of radiation. The PIR sensors are tuned in such a way that they detect only the radiation emitted by human beings. 

The working of this security system is very simple as well.Here a PIR sensor is used for sensing and then arduino used for controlling and then A GSM module which is used for calling purpose. When anybody comes in range of PIR sensor, then sensor sends a logic signal to Arduino board which control and perform the specified task. Here arduino board sends signals to GSM module and gives a call on a set number.  

Did you know that most of the thefts at home happen when it is empty? But not everyone is rich enough to hire a security for their house and at the same time they themselves cannot be at home 24 by7. Now what if there is a system which alerts you about an intruder through a text message?The following tutorial teaches how to make you own intruder alerting system