passive infrared motion sensors
TRANSCRIPT
• UNIQUE FEATURES• OF• PIR MOTION SENSORS
INTRODUCTION
They use built-in amplifier to detect motion
The IR module is specifically used to detect IR radiation (body heat) from the human body
They can also detect other things that generate IR radiation
INTERNAL COMPONENTS
A built-in amplifier to convert IR radiation to voltage
A comparator for converting output to digital form
A stabilized power supply unit to supply power to the circuit
A quad-type pyroelectric element to detect movement within its range
DETECTION OF MOVEMENT
The quad-type pyroelectric element has 4 similar receptors The sensor can pick up even the
smallest movements within the receptor’s range
This makes PIR motion sensors more accurate and effective
WORKING PRINCIPLES
IR motion sensors detect radiation instead of emitting them
The inverting input becomes low when the sensor detects IR radiation
Then the comparator’s output increases and lights up the LED
3 different resistors in the IC transfer current to all internal components
TYPES OF IR SENSORSIR sensors are of different types depending on their usage
Temperature sensors detect temperature
PIR sensors are used for home/commercial
security
Ultrasonic sensors can measure
distance between two points
FOCUSING MECHANISM IN IR SENSORS
OR
PIR motion sensors use
LENS MIRROR
The main task of lenses/mirrors is to focus light onto the
sensor
Mirrors have slightly more range
than lenses
HOW TO AVOID FALSE DETECTIONS
Avoid placing them on the wall directly facing
the window
Avoid installing PIR motion detectors near HVAC vents that blow
cold/hot airInstall them high up on the wall to avoid being triggered by toddlers and pets
THANK YOU