Embedded Files
This project simulates a theft detection and alert system using a PIR motion sensor connected to an Arduino UNO. The system detects unauthorized movement using the PIR sensor. When motion is detected (such as a person entering a restricted area), the Arduino triggers a buzzer and LED to alert the user, simulating a real-world theft alert scenario.The PIR sensor constantly monitors for infrared radiation (body heat).When it detects motion (a person moving), it sends a HIGH signal to the Arduino.The Arduino then turns ON the buzzer for an audible alarm and turns ON the LED for a visual alert.If no motion is detected, both the buzzer and LED remain OFF.
Components:
Arduino Uno
PIR sensor
Buzzer
LED
Resistor 220 ohm
Bread board
Jumper wires
Working of PIR Sensor:
PIR sensors are more complicated than many of the other sensors because there are multiple variables that affect the sensor’s input and output.
Working of PIR Sensor
The PIR sensor itself has two slots in it, each slot is made of a special material that is sensitive to IR. The lens used here is not really doing much and so we see that the two slots can ‘see’ out past some distance (basically the sensitivity of the sensor). When the sensor is idle, both slots detect the same amount of IR, the ambient amount radiated from the room or walls or outdoors. When a warm body like a human or animal passes by, it first intercepts one-half of the PIR sensor, which causes a positive differential change between the two halves. When the warm body leaves the sensing area, the reverse happens, whereby the sensor generates a negative differential change. These change pulses are what is detected.
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