post details Interfacing-PIR-Motion-Detector-Sensor-8051-Microcontroller | Interface-Motion-Sensor-Module-89C51-Microcontrollers
Interface Motion Detecting PIR Sensor Module - 8051 Microcontrollers
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Interfacing Motion Detector PIR Sensor With 8051 Microcontroller Family Models
 
Atmel, NXP, Philips, 8051, 8052, 89C51, 89C52, 89S51, 89s52, 89C1051, 89C1051, 89C2051, AT89C4051, AT89S8252,l AT89C1051, AT89C2051, AT89C4051,P89C51RB+, P89C51RC+, P89C51RD+, P89C51RB2Hxx, P89C51RC2Hxx, P89C51RD2Hxx, P89C660, P89C662, P89C664, P89C668, P89C669, P89C51RA2xx, P89C51RB2xx, P89C51RC2xx, P89C51RD2xx, P89C60X2, P89C61X2,P89LV51RB2, P89LV51RC2, P89LV51RD2, P89V51RB2, P89V51RC2, P89V51RD2, P89V660, P89V662, P89V664.
 
Motion Detector PIR (Passive Infra Red) Sensor 8051 Microcontroller
Motion Detector PIR (Passive Infra Red) Sensor 8051 MicrocontrollerThis tutorial  project explains how a motion detector sensor works . PIR sensor is based on Passive Infra Red technology. The human body radiates infrared waves with wavelengths of 8 to 12 micrometers. Any movement by a person leads to a change in the amount of infrared energy which a sensor can detect within its range. The PIR sensor reacts to this change in infrared energy and provides a low-frequency, small amplitude signal. The sensor can sense and measure  the change in the amount of infrared energy within small distances, approximately up to 10 inches. For detecting movements at longer distance, infrared radiation has to be measured by the sensor. This beautiful job is done by by a Fresnel lens. A Fresnel lens divides the whole area into different zones. Any movement between zones leads to a change in the IR (infrared) energy received by the sensor. They can be interface with any 8051, 8052, 89C51, 89C52, 89S51, 89s52 Microcontroller as per need.
 
Features Of PIR Motion Detectors
PIR Motion Detector has very marvelous and reliable features. It is very reliable device which works in its own way when integration with Microcontrollers. They have following features :
 
  • PIR & Motion Detection IC and Fresnel Lens
  • Simple 3 Pin Connections
  • Dual Element Sensor with Low Noise and High Sensitivity
  • Supply Voltage: 5V DC
  • Standard Active Low Output Pin Can Be Connected Directly With Microcontroller
  • Detecting Range Up To 6 Meters
  • LED Indication (Optional Some Sensor Has)
  • Small in Size Probabaly25mm Length, 32mmWidth, 25mm Height -
 
Applications Can Be Developed Using PIR Motion Sensor
PIR sensors are small in size and very economical and easily available in the market. They can be interface easily with any ATMEL AT89C51, AT89C52, AT89S51, AT89s52 Microcontroller. Hundreds of documentation and help is available on the internet to study and interface. Some basic and common applications are as follows where PIR Motion Detectors can be used:
 
  • Security Systems
  • Automatic lighting
  • Systems Automatic
  • Door Openers
  • Motion Activated Nightlight
  • Alarm systems Robotics
 
Theory Of Working  PIR Motion Detector Sensor
Pyroelectric devices, such as the PIR motion detector sensor, have elements made of a crystalline material that generates an electric charge when exposed to infrared radiation. The changes in the amount of infrared striking the element change the voltages generated, which are measured by an on-board amplifier. The device contains a special filter called a Fresnel lens, which focuses the infrared signals onto the element.
 
As the ambient infrared signals change rapidly, the on-board amplifier trips the output to indicate motion. The PIR (Passive Infra-Red) Sensor is a pyroelectric device that detects motion by measuring changes in the infrared (heat) levels emitted by surrounding objects. This motion can be detected by checking for a sudden change in the surrounding IR patterns. When motion is detected the PIR sensor outputs a high signal on its output pin. This logic signal can be read by a microcontroller or used to drive a transistor to switch a higher current load.
 
Warm Up time Preparing For Working
The PIR Sensor needs some warming up time to work properly and prepared itself for communicating with microcontroller. This is because of internal setting to judge the environment. Time may be taken from 1-2 minutes for warming up. After warming up is over then the sensor is ready to respond to microcontroller.
 
  
Interfacing And Working With 8051 Microcontroller
Connect regulated DC power supply of 5 Volts to the positive power supply of sensor and connect another pin to Ground, Next the middle wire is output and connect the pin to directly to the microcontroller to send the motion detecting signal. After powering up leave it for 1-2 minutes before using the sensor for warming up. Now sensor is ready to use for connecting with microcontroller. The changes in the amount of infrared striking the element change the voltages generated, which are measured by an on-board amplifier. The device contains a special filter called a Fresnel lens, which focuses the infrared signals onto the element. As the ambient infrared signals change rapidly, the on-board amplifier trips the output in low signal to indicate about the motion.