Overview

The Passive Infrared Sensor (PIR) module is a widely used motion detection component that senses infrared radiation from humans or animals. It detects changes in infrared levels caused by motion within its range and outputs a digital signal. This module features a pyroelectric sensor, a dome-shaped Fresnel lens for wider coverage, and adjustable delay and sensitivity settings, making it ideal for home automation, security systems, and energy-saving lighting applications.

Features

• Detects motion by sensing infrared radiation changes

• Adjustable sensitivity and time delay via onboard potentiometers

• Wide detection range with 120° field of view

• Built-in Fresnel lens for enhanced sensing distance

• Digital HIGH output when motion is detected

• Energy efficient, ideal for battery-operated devices

• Compatible with 3.3V and 5V logic

Technical Details

• Operating Voltage: 4.5V to 20V DC

• Output Type: Digital (HIGH = motion detected)

• Detection Range: 3–7 meters (adjustable)

• Detection Angle: 120°

• Delay Time: Adjustable (0.3 – 300 seconds)

• Trigger Modes: Repeatable and non-repeatable

• Module Size: ~32mm x 24mm

Pin Descriptions

• VCC: Connect to 4.5V–20V power supply

• GND: Ground

• OUT: Digital signal output (HIGH when motion is detected)

Working Principle

The PIR module uses a pyroelectric sensor to detect infrared radiation. When a warm body like a human or animal passes through the sensing area, the infrared levels change rapidly. This change is detected by the sensor, which triggers the comparator circuit to output a HIGH signal. Sensitivity and delay can be tuned using the two onboard potentiometers.

Common Applications

• Automatic lighting systems

• Burglar and intruder alarms

• Motion-triggered video recording

• Smart home automation

• Energy-saving HVAC systems

• Pet or human motion tracking

Helpful Resources

• Arduino Project with Code (Randomnerd):