HC-SR505 Mini PIR (Passive Infrared) Motion Sensor

HC-SR505 Mini PIR Motion Sensor

What is it?

The HC-SR505 is a mini Passive Infrared (PIR) sensor used to detect human or animal motion by sensing infrared (heat) radiation. It outputs a digital signal when motion is detected.

Key Features (Infographic Points)

Core Features

• Detects infrared radiation from living beings

• Ultra-low power consumption (ideal for battery projects)

• Compact size (perfect for small devices)

• Repeatable trigger mode (default)

Technical Specifications

• Operating Voltage: 4.5V 20V DC

• Detection Range: ~3 meters

• t / LOW (0V)

• Delay Time: ~8 seconds (adjustable in some variants)

• Current Consumption: < 60 A (very low)

• Working Temp: -20C to +80C

How It Works

• Detects changes in infrared heat radiation

• When a person enters range Output goes HIGH

• After motion stops Output returns LOW after delay

• If motion continues delay resets automatically

Pin Configuration

• VCC Power (5V12V typical)

• OUT Digital output signal

• GND Ground

( 10 23 mm)

Easy interface with:

• Arduino

• ESP32

• Raspberry Pi

Limitations

• Shorter range than larger PIR sensors (like HC-SR501)

• Sensitive to electrical noise in some setups (needs stable power)

• Limited adjustability (fewer controls than bigger modules)

Common Applications

• Automatic lights (motion-based)

• Security & intrusion detection

• Robotics motion sensing

• Smart toys / IoT devices

• Battery-powered automation systems

Pro Tips

• Keep sensor away from heat sources (fans, sunlight)

• Use stable> for best detection