SR501 PIR Sensor Infrared Motion Detector
The SR501 PIR Sensor is a popular, reliable, and cost-effective passive infrared motion detector designed to sense human or animal movement. It detects changes in infrared radiation emitted by warm objects within its sensing range. Due to its high sensitivity and wide detection angle, it is widely used in security systems, automatic lighting, and energy-saving applications. The sensor operates on a wide voltage range, making it compatible with most microcontrollers and embedded systems.
How It Works
The SR501 PIR sensor contains a pyroelectric sensor that detects infrared energy emitted from moving bodies. When a warm object moves within the detection zone, it causes a change in the IR radiation received by the sensor, triggering the output signal. The sensor module includes an onboard potentiometer that allows you to adjust sensitivity and delay time, offering flexible control over detection range and response duration. Additionally, the sensor features a wide viewing angle and a detection range of up to 7 meters, making it suitable for indoor and outdoor use.
Key Features
Wide operating voltage: 4.5 V to 20 V DC
Detection distance: Up to 7 meters
Detection angle: Approximately 110°
Adjustable sensitivity and delay time via onboard potentiometers
Low power consumption for battery-powered applications
Digital output signal for easy interface with microcontrollers
Compact design for versatile integration
Specifications
| Parameter | Value |
|---|---|
| Operating Voltage | 4.5 V – 20 V DC |
| Detection Distance | Up to 7 meters |
| Detection Angle | ~110° |
| Output Type | Digital (HIGH/LOW) – |
| Current Consumption | < 50 µA (standby) |
| Operating Temperature | –15 °C to +70 °C |
| Module Size | ~32 mm × 24 mm |
Pin Configuration
| Pin | Name | Description |
|---|---|---|
| 1 | VCC | Power supply input (4.5 V–20 V DC) |
| 2 | OUT | Digital output (HIGH on motion) |
| 3 | GND | Ground reference |
Applications
Motion-activated lighting systems
Security and alarm systems
Energy-efficient automation devices
Robotics and smart home projects
Intruder detection
