Meaning of PIR sensors
The term "passive" indicates that the sensor does not actively emit the IR signals but passively detects the infrared radiations coming from the human body from the surrounding area. Generally speaking like any other motion sensor, PIR sensor is something that detects infrared energy omitted by human or animal body from a considerable distance with the help of a crystalline material. This material is located in the field of view and sends out signals to the control system which can trigger the alarm when there is any movement. To be more accurate the detector analyses the change by measuring the difference which occurs in the amount of infrared radiation in a particular location. PIR sensors are mostly used in outdoor and indoor environments in the form of security lights and alarm systems. The usual range for PIR sensor is 6 meters but they can also be adjusted in different ranges. Due to its small size, long lasting life, less cost and convenience in using, these lights have gained much popularity appreciably.Different types of PIR sensor:

- Alarm system PIR sensors

- Motion light PIR sensors
These type of security lights are good for increasing the efficiency of outdoor lighting (outdoor flood lights) or the hallway. Since Motion light PIR sensor has adjustable PIR sensor range and illumination time it can also be used indoors. It can also save maximum energy if you are using the proper type of bulb-LED bulbs.

- Video motion sensors
Some of the commonly used areas are:
- Yards of private houses;
- Front-door;
- Hallways of office buildings;
- Parking lots
- The range of detection
- Distance of the detection
- Placement
- Lamps
- Pet-immune sensor
- Resistance
- Solar panel equipped motion lights.