Passive Infrared Receiver (PIR)

PIR (Passive Infrared Receiver) is a sensor based on infrared. However, unlike most of the infrared sensor, which consists of an IR LED and fototransistor. PIR does not emit any such IR LEDs. As the name ' Passive ', this sensor only responds to the energy of the beams passive infrared that is owned by any objects detected. An object that can be detected by these sensors are usually the human body. PIR sensor KC7783R is the sensor that will produce output with high level between 5-6 volts.

In PIR sensor, there are parts that have the role of each Fresnel Lens, IR Filter, Pyroelectric sensor, amplifier and comparator.

 

PIR Sensor works by capturing the heat energy generated by passive infrared beams which belonged to every object with temperature above absolute zero objects. Like the human body that has a body temperature of approximately 32 degrees centigrade, which is the temperature of the heat that is typical of that found in the environment. A steady stream of infrared light is then captured by the Pyroelectric sensor which is the core of the PIR sensor is causing Pyroelectic sensor comprising gallium nitride, cesium nitrate and lithium tantalate produces an electric current. Why can generate an electric current, this is because this passive infrared beams carry heat energy. The process is almost the same as an electric current that is formed when sunlight hit the solar cell.

 

Passive Infrared Receiver System

 

Why is PIR sensor only reacts in the human body only, this is caused due to an IR Filter which filters wavelengths of infrared light passive. IR Filter dimodul PIR sensor is capable of filtering out infrared light wavelengths between passive 8 to 14 micrometres wavelength, so that the resulting from human body ranges from 9 to 10 micrometers this alone that can be detected by the sensor.

 

So, when someone walks past the sensor, the sensor will capture passive infrared beams emitted by the human body that have different temperature of the environment causing pyroelectric materials react to generate electricity because of the thermal energy carried by passive infrared rays. Then an amplifier circuit amplifies the current existing are then compared by the comparator to produce output.

 

When the man was in front of PIR sensor with the condition is silent, then the sensor PIR will calculate the wavelength produced by the human body. This constant wavelength causes the heat energy produced can be described pretty much the same on the surrounding environmental conditions. When the man doing the movement, the human body will produced beams passive infrared wavelengths that vary so as to produce heat is different that causes the sensor to respond by way of generating current in Pyroelectricnya materials with different magnitudes. Because different quantities is the comparator output.

 

So the sensor PIR will not produce output when the sensor is exposed to the heat of objects that do not have the infrared wavelengths between 8 to 14 micrometres and objects such as light rays are still very bright light that is able to generate heat, the objects reflection from the mirror and the temperature when hot summer.