PIR sensor is capable of distinguishing between human and object movement.Related Post: Types of Resistive Sensors – Transducer, Potentiometer & Strain Gauge.PIn3 is GND pin, generally connected with ground.Pin 2 is output pin which gives logic HIGH or LOW when detects motion.
Pin 1 is Vcc which is connected positive 5V supply.Pin1, Pin2, and Pin3 are corresponded to drain, source and Ground terminal of the device. The passive infrared sensor consists of three pins as shown below. Go through the given diagram of the PIR sensor to understand its pin-outs and arrangement in the circuit. In both the operating modes, the sensitivity can be controlled using the “sensitivity control” potentiometer present on the board. And, as soon as the object goes out of the sensing range, the output will again go to low. In this mode, the output will go high as soon as the motion is detected in the range of PIR sensor. This preset timing and sensitivity can be controlled by the potentiometer present on-board. Means the output will remain high even the person or object left the PIR range of detection. In this mode, the output pin will go high once the motion is detected and goes low after a preset time. There are mainly two operating modes of PIR sensor “Repeating mode” and “Non-repeating” mode. Once the module is powered, then it allows the module to calibrate itself for 2 minutes. It operates at 4.5V to 20V, depending upon the requirement, typically 5V power is used. Understanding the modes of operation of a PIR sensor eases the design process of your electronic circuit. Again, when the object leaves the sensing area of the sensor, it generates negative differential change between two bisects. Whenever the human body or object passes by, then the first slot of the sensor is being intercepted causing a positive differential change between two bisects. As long as the sensor is inactive, the two slots sense the same amount of Infrared. PIR sensor consists of two slots made up of materials sensitive to IR. This charge is further modified and improved by the built-in FET and given to the output pin of the device. PIR converts the detected radiation electrical charge. The pyroelectric sensor detects the heat from an object or body and Fresnel lens widens the range of the sensor. The first one is the pyroelectric crystal and the second one is Fresnel lenses. Related Post: What is a Sensor? Different Types of Sensors with ApplicationsĬoming to the discussion of materials used in the PIR sensor, there are mainly two important parts present in the PIR sensor module.The output of the PIR sensor goes high when it detects infrared rays in its range. PIR sensor doesn’t emit infrared signal by itself in fact, it detects infrared radiation coming from the body or object in its surrounding area. That means the sensor acts as digital output and gives “high or low” depending upon the situation. Whenever the motion is detected, the signal pin goes high. One is a signal pin, second is for Ground and the third one is for power supply. PIR sensors module comes with three pins for interfacing with any microcontroller. And, the infrared region of PIR sensor is from 0.75um to 1000um. There are three IR regions on spectrum named as near-infrared (0.75-3um), mid-infrared (3-6um), and far infrared (higher than 6um). PIR sensor stands for Passive Infrared Sensor. Applications of Infrared Motion Detector and Sensor.Circuit Diagram For Motion Detector Circuit.