HC-SR501 PIR Motion Sensor Module – Human Body Infrared Motion Detector for Arduino, Raspberry Pi, and IoT Projects
The HC-SR501 PIR Motion Sensor Module is a highly reliable, easy-to-use sensor designed to detect human motion by measuring infrared (IR) radiation changes in its environment. This compact and cost-effective module is perfect for security systems, motion-activated lighting, and automation projects.
“PIR” stands for Passive Infrared Sensor, which detects heat emitted naturally by living beings. When a person enters or leaves its detection range, the sensor outputs a digital HIGH signal, making it ideal for motion-triggered systems.
The module includes an onboard pyroelectric sensor with a Fresnel lens to extend detection range and accuracy. It also features two adjustable potentiometers to fine-tune detection distance and delay time, giving you complete control over sensitivity and trigger duration.
This module is compatible with Arduino, Raspberry Pi, ESP8266, ESP32, AVR, PIC, ARM, and 8051 microcontrollers, making it ideal for beginners and advanced makers alike.
Key Features
- Detects human motion using passive infrared sensing
- Adjustable sensitivity (up to 7 meters) and delay time (5s–200s)
- Digital output: HIGH when motion detected
- Detection range: 3m – 7m (adjustable)
- Low power consumption and stable performance
- Trigger mode: Re-triggerable or non-retriggerable (configurable)
- Onboard indicator LED for motion status
- Compatible with Arduino, ESP8266, ESP32, Raspberry Pi, and more
- Compact and easy to integrate in DIY or professional systems
Adjustable Settings
- Sensitivity (Distance):
- Rotate clockwise → Increase detection range (up to ~7m)
- Rotate counterclockwise → Decrease range (~3m)
- Delay Time (Hold Time):
- Rotate clockwise → Increase delay (up to ~200s)
- Rotate counterclockwise → Decrease delay (~5s)
- Default Block Time: ~2.5 seconds
Technical Specifications
- Model: HC-SR501
- Operating Voltage: 4.5V – 20V DC
- Quiescent Current: < 50 µA
- Output Level: HIGH = 3.3V, LOW = 0V
- Detection Distance: 3 – 7 meters (adjustable)
- Delay Time: 5s – 200s (adjustable)
- Trigger Modes: Re-triggerable / Non-retriggerable
- Sensor Type: Dual Element Infrared (Pyroelectric)
- Lens Type: Fresnel Lens
- Dimensions: 32mm × 24mm × 18mm (approx.)
Circuit Diagram
The HC-SR501 connects easily with Arduino or similar microcontrollers using just three pins:
| Pin | Description |
|---|---|
| VCC | Connect to 5V (or 3.3V) power supply |
| OUT | Digital signal output (HIGH when motion detected) |
| GND | Ground connection |
Connection Example (with Arduino Uno):
- VCC → 5V
- OUT → Digital Pin 7 (or any digital input)
- GND → GND
Below is the circuit diagram illustration:
Applications
- Home & Office Security Systems
- Automatic Lighting Control
- Smart Home Automation
- Human Detection in IoT Devices
- Energy-Saving Motion-Triggered Systems
- Robotics and Human Interaction Systems
Package Includes
- 1 × HC-SR501 PIR Motion Sensor Module
Note
When powering up the module, allow 30–60 seconds for calibration. During this time, the sensor may output random signals — this is normal and expected.
Product appearance or color may vary slightly depending on stock, but functionality remains identical.
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