sensor.pptx
- 1. PIR SENSOR (PASSIVE INFRARED SENSOR)
- 2. PIR (passive infrared) sensors utilize the detection of infrared that is radiated from all objects that emit heat. This type of emission is not visible to the human eye, but sensors that operate using infrared wavelengths can detect such activity. They are sometimes referred to as ‘motion- based detectors’, as they sense the presence of people, animals and objects through the movement of their infrared wavelengths.
- 3. They are referred to as “passive” due to the fact that no heat or energy is emitted by the sensor itself. It is also important to remember that PIR sensors detect the emission of infrared radiation, and not heat.
- 4. Pin1 corresponds to the drain terminal of the device, which connected to the positive supply 5V DC. Pin2 corresponds to the source terminal of the device, which connects to the ground terminal via a 100K or 47K resistor. The Pin2 is the output pin of the sensor. The pin 2 of the sensor carries the detected IR signal to an amplifier from the Pin3 of the sensor connected to the ground.
- 7. The pin configuration of the PIR sensor is shown in the figure. PIR sensor consists of three pins, ground, signal, and power at the side or bottom. Generally, the PIR sensor power is up to 5V, but, the large size PIR modules operate a relay instead of direct output. It is very simple and easy to interface the sensor with a microcontroller. The output of the PIR is (usually digital output) either low or high.
- 9. The PIR sensor circuit consists of three pins, power supply pin, output signal pin, and ground pin. The PIR sensor circuit is having ceramic substrate and filter window as shown in the figure and also having dome like structure called as Fresnel lens.
- 12. • Typically , the FET source terminal pin 2 connects through a pulldown resistor of about 100k to ground and feeds into a two stage amplifier having signal conditioning circuits. • The amplifier is typically BW limited below 10H to reject high frequency noise and is followed by a window comparator that responds to both +VE & -VE transitions of the sensor output signal. • A well filtered power source of from 3 to 15 volts should be connected to the FET drain terminal pin 1.
- 13. PYROELECTRIC
- 14. A Pyroelectric sensor is very sensitive to rapid temperature changes. A rapid change in air temperature due to a breeze from an open window or from an air conditioner or heater can cause false triggering. The shadow and pin hole lenses described above do not offer protection against such air movement because they are actually open lenses For outdoor use we need protection against rain.
- 15. WHAT PIR DOES
- 16. PIR sensor can detect animal/human movement in a requirement range. PIR is made of a pyroelectric sensor, which is able to detect different levels of infrared radiation. The detector itself does not emit any energy but passively receives it. It detects infrared radiation from the environment. Once there is infrared radiation from the human body particle with temperature, focusing on the optical system causes the pyroelectric device to generate a sudden electrical signal.
- 17. Simply, when a human body or any animal passes by, then it intercepts the first slot of the PIR sensor. This causes a positive differential change between the two bisects. When a human body leaves the sensing area, the sensor generates a negative differential change between the two bisects.
- 18. The passive infrared sensor does not radiate energy to space. It receives the infrared radiation from the human body to make an alarm. Any object with temperature is constantly radiating infrared rays to the outside world. The surface temperature of the human body is between 36° C - 27 ° C (96 F - 80.6F)and most of its radiant energy concentrated in the wavelength range of 8 μm-12 μm.
- 19. Passive infrared alarms classified into infrared detectors(infrared probes) and alarm control sections. The most widely used infrared detector is a pyroelectric detector. It uses as a sensor for converting human infrared radiation into electricity. If the human infrared radiation is directly irradiated on the detector, it will, of course, cause a temperature change to output a signal.
- 20. But in doing all this, the detection distance will not be more. In order to lengthen the detection distance of the detector, an optical system must be added to collect the infrared radiation. Usually, plastic optical reflection system or plastic Fresnel lens used as a focusing system for infrared radiation.
- 21. In the detection area, the lens of the detector receives the infrared radiation energy of the human body through the clothing and focused on the pyroelectric sensor. When the human body moves in this surveillance mode, it enters a certain field of view in sequence and then walks out of the field of view. The pyroelectric sensor sees the moving human body for a while and then does not see it, so the infrared radiation of human body constantly changes the temperature of the pyroelectric material. So that it outputs a corresponding signal, which is the alarm signal.
- 23. A PIR sensor module has only 3 pins – one is Vcc which is a +5 volts input, a ground pin and finally the digital output pin. Connect +5V from Arduino to Vcc of PIR sensor module, connect a GND from Arduino to ground of PIR sensor . finally connect the output pin (marked as 'out') to any digital pin of Arduino.
- 24. As like we can connect PIR sensor to Raspberry Pi Pic micro controller AVR 8051
- 25. Indoor passive infrared : 25 cm to 20 m. Indoor PI curtain type : 25 cm to 20 m. Outdoor PI : 10 m to 150 m. Outdoor PI curtain detector: 10 m to 150 m.
- 27. All outdoor Lights Lift Lobby Multi Apartment Complexes Common staircases For Basement or Covered Parking Area Shopping Malls For garden lights