HCSR501 PIR Motion Sensor (Passive Infrared Sensor)
HC-SR501 PIR Motion Sensor
Human Motion Detection Low Power Smart Automation
The HC-SR501 PIR Motion Sensor Module is a widely used Passive Infrared (PIR) sensor designed to detect motion from humans or animals by sensing changes in infrared radiation. It is commonly used in security systems, automatic lighting, robotics, and IoT projects.
The module includes a pyroelectric infrared sensor and Fresnel lens that helps detect movement within its detection range.
Infographic Overview
Basic Specifications
Feature | Details | |
Operating Voltage | 5V 20V DC | |
Operating Current | ~50 A (very low power) | |
Output Type | Digital (Hi Detection Angle | ~120 |
Delay Time | Adjustable (3s 5 min) | |
Operating Temperature | -15C to +70C |
Main Components (Based on the Image)
The module typically contains:
Fresnel Lens Dome focuses infrared signals PIR Sensor Element detects infrared radiation changes BISS0001 Controller IC signal processing chip Sensitivity Adjustment Potentiometer Delay Time Adjustment Potentiometer Voltage regulator & capacitors
Pin Configuration
Pin | Function |
VCC | Power supply (520V) |
OUT | Digital output signal |
GND | Ground |
Working Principle
The PIR sensor detects infrared radiation emitted by warm objects like humans.
Step-by-Step Operation
1 The Fresnel lens focuses infrared radiation onto the sensor.2 The PIR element detects changes in heat energy.3 When a human or animal moves, IR levels change.4 The controller IC processes the signal.5 The module outputs HIGH signal when motion is detected.
Sensor Layout (Simplified)
HC-SR501 PIR Motion Sensor Fresnel Lens (Motion Detection)Wostments Sensitivity Delay Time Pins'VCC OUT GND
Adjustable Settings
The HC-SR501 has two adjustable potentiometers:
Sensitivity Adjustment
Controls motion detection distancepatible Microcontrollers
The PIR sensor can easily connect to popular development boards:
Arduino Uno
ESP32
Arduino Nano
Raspberry Pi
Advantages
Very low power consumption Wide detection angle (~120) Adjustable sensitivity and delay Easy digital output interface Ideal for motion detection systems
Limitations
Cannot detect stationary objects Sensitive to temperature changes False triggers possible from pets or heat sources
Example Project Idea
Automatic Motion-Activated Light
Components
PIR Motion Sensor (HC-SR501)
Arduino Uno
Relay module Microcontroller activates relay Light turns ON automatically Light turns O