HC-SR501 PIR Motion Sensor Module

HC-SR501 PIR Motion Sensor Module

Product Description

The HC-SR501 PIR Motion Sensor Module is a reliable and adjustable Passive Infrared (PIR) motion sensor designed to detect movement of humans and animals by sensing changes in infrared radiation. It is widely used in home security, automatic lighting, robotics, industrial automation, Arduino, Raspberry Pi, and ESP32 projects.

The module features a high-sensitivity dual-element PIR sensor with a Fresnel lens that provides a wide detection area. Its adjustable controls allow users to configure both the detection distance and the output delay according to project requirements.

Adjustable Sensitivity and Delay

The HC-SR501 includes two onboard potentiometers for convenient adjustment.

Sensitivity Adjustment

The sensitivity control allows the detection range to be adjusted from approximately 3 meters to 7 meters.

• Clockwise: Increases detection distance
• Counterclockwise: Decreases detection distance

Time Delay Adjustment

The time-delay control determines how long the output remains HIGH after motion is detected.

• Clockwise: Increases delay
• Counterclockwise: Decreases delay
• Adjustable from approximately 5 seconds to 200 seconds

High-Sensitivity PIR Detection

The module uses a dual-element infrared sensor combined with a Fresnel lens to detect changes in infrared energy caused by moving objects. When motion is detected, the module produces a HIGH 3.3V TTL output.

When no motion is detected, the output returns to LOW 0V.

Low Power Operation

With a static current consumption of less than 60µA, the HC-SR501 is suitable for applications where low power consumption is important, including battery-operated security systems and automatic lighting projects.

Key Features

• Passive infrared motion detection
• High-sensitivity dual-element PIR sensor
• Fresnel lens for wide-area detection
• Adjustable detection distance
• Adjustable output delay
• 3m–7m detection range
• <140° detection angle
• Low static current consumption
• 4.5V–20V DC operating voltage
• Digital HIGH/LOW TTL output
• Suitable for Arduino, Raspberry Pi, and ESP32
• Compact and easy-to-mount design

Technical Specifications

Feature	Specification
Model	HC-SR501
Operating Voltage	4.5V – 20V DC
Static Current	<60µA
Output Level	HIGH 3.3V / LOW 0V TTL
Detection Range	3m – 7m Adjustable
Detection Angle	<140° Cone Angle
Delay Time	5s – 200s Adjustable
Blockade Time	2.5s Default
Dimensions	32mm × 24mm × 18mm
Operating Temperature	-20°C to +80°C

Working Principle

The HC-SR501 detects changes in infrared radiation emitted by objects within its sensing area. When a person or animal moves through the detection zone, the change in infrared energy is detected by the PIR element.

The onboard processing circuit then generates a digital output signal. The output becomes HIGH (3.3V) when motion is detected and LOW (0V) when the sensor is idle.

Output Interface

The module provides a digital TTL-compatible output that can be connected to a microcontroller or control circuit.

• HIGH (3.3V): Motion detected
• LOW (0V): No motion detected

This makes the module easy to integrate with Arduino, Raspberry Pi, ESP32, relay modules, alarms, and automation controllers.

Typical Application Scenarios

Home Security

Suitable for burglar alarms, intrusion detection systems, and motion-triggered security devices.

Automatic Lighting

Can be used to automatically control hallway, bathroom, stairway, and room lighting when movement is detected.

Robotics

Useful for robots that need to detect nearby human movement and respond accordingly.

Industrial Automation

Can be integrated into access control systems, automatic doors, and other motion-triggered equipment.

Applications

• Home security systems
• Burglar alarms
• Intrusion detection
• Automatic lighting
• Smart home automation
• Motion-activated switches
• Robotics
• Automatic doors
• Access control systems
• Industrial automation
• Arduino projects
• Raspberry Pi projects
• ESP32 projects
• DIY IoT projects

Package Includes

• 1 × HC-SR501 PIR Motion Sensor Detector Module

Product Disclaimer

Product information provided on our website may not be entirely accurate as specifications can vary between manufacturers, suppliers, and production batches. Please verify the actual product specifications before using the module in critical applications.

Product images are for illustrative purposes only and may differ from the actual product in colour, component placement, dimensions, or other visual details.

This sensor is intended for general motion detection and should not be considered a standalone safety or security system for critical applications.

Important Note

Sensitivity Adjustment

Turn the sensitivity potentiometer clockwise to increase the detection distance up to approximately 7m. Turn it counterclockwise to reduce the range toward approximately 3m.

Time Adjustment

Turn the time-delay potentiometer clockwise to increase the output delay up to approximately 200 seconds. Turn it counterclockwise to reduce the delay toward approximately 5 seconds.

Warm-Up Period

After the sensor is powered on, allow approximately 30–60 seconds for the module to settle and calibrate to the surrounding infrared environment. False triggers may occur during this initial period.

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