The Passive Infrared Sensor (PIR) is an electronic device used for security surveillance purposes. It is an alarm system that can tell whether there is a silent encroacher within the periphery of its surveillance. The PIR detector is extensively used as home alarms with multi-purpose surveillance functions and is a great tool providing wholesome protection to your home.
How a PIR Sensor works?
A PIR detector can locate any kind of motion within its field of vision by means of detecting temperature difference between the normal temperature of the area and the sudden fluctuation of the temperature due to the presence of any object especially human beings. The PIR Sensor module is so devised that it can capture infrared radiation from the object that comes under its coverage, which is not perceived by normal human senses. As the detector only receives the radiation without emitting it back, it’s known as Passive Infrared Sensor. It is based on the theory that every object including human beings radiate infrared energy and the PIR motion sensor catches the variation in the temperature due to sudden change in energy level in one particular place. If the device is armed, it sends an alarm. Depending upon the type of device installed, the PIR sensor could be used for multiple alarm signals like sending voice alert or switching the lights or both. However, it is so designed that the gradual change that takes place in the climate throughout the day is not perceived by the sensor.
Where and how to place the PIR motion detector?
The positioning of the detector is vital for it to give accurate signals. As its function depends on reading energy radiation, it has to be placed from where it can cover a larger area and be able to detect any change in the temperature. The ideal position is to place it a little tilted at an angle of about 8 degrees downwards. Placing it at that angle makes the sensor function better because it receives radiation of objects that cut across its path better than those that move directly towards it. However, the device should not be placed in the kitchen, near the window, over a heater or AC or where it can get direct sunlight. These are the heating and pressure fluctuation zones where the detector cannot function properly to register changes in temperature and would possibly ring false alarm. You should also keep in mind that PIR motion sensor works best in ambient atmosphere and the best place to keep the sensor is in the corner of a room at a height of about 2meters from the ground away from sunlight.
PIR motion sensor installation and wiring
The effectiveness of a PIR sensor module depends on its proper installation. Faulty installation would cause false alarm. It could either be mounted vertically, angular or at the ceiling and one should take care of not spoiling the case and the PIR sensor which is just in the middle of the module. The wiring is another big affair for the sensor to work accurately. For the installation of a 12V sensor, the wiring should be done parallel to the other wiring and connected to the controlling unit. These days’ wireless PIR sensors are more in use as they can be installed without the hassles of wiring and work simply on rechargeable batteries. But generally PIR sensors could be used randomly as they consume low power and are cost effective.
Limitations of PIR sensors
It is suggested that when you are installing PIR detector alarm, you should take into notice the conditions under which it works and doesn’t work. The best way of knowing how it works is through a few trials, and every time you hear a false alarm you know where to rectify. But if the pulse count feature incorporated in the machine is set according to the environment, it acts as anti-false alarm agent. The more the pulse count, the highest pulse count being 3, the sensor would require more movement to register temperature variation. The pulse count works positively in restraining false alarms created by strong wind or insects but on the negative side it fails to detect slower movement. However, some of the basic limitations are: keeping the device away from sources of heat and vibration like sunlight, wind, from obstruction like a wall through which IR cannot pass and last but not the least keeping your pet away from straying into its coverage area.
Availability and cost of PIR security sensor
PIR sensor is largely used for security devices and is readily available in the market. In fact, with increasing awareness among people regarding the requirement of greater personal security along with the penchant for trying out new technology, PIR motion detectors are greatly in demand. The cost of the average model is around $ 20 which is within affordable range. If you want to install one, you can either order from security retailers or order online. But before going for this new device make sure to read the manual.
The Passive Infrared Sensor or PIR is an electronic device, which is used for safety and security of the house. This alarm system is highly efficient to detect encroacher within the periphery of its surveillance. Used extensively home alarms with multi-purpose surveillance functions, it is a great offering complete protection to the homes.
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