HCSR501 human body infrared sensitive module Quick overview The HCSR501 is a compact passive infrared motion detection module designed to detect human body movement reliably. It converts infrared signals from moving heat sources into a clean digital output that is easy to integrate into control systems and microcontroller projects. Key benefits Reliable motion detection for real world use: Detects moving humansized heat sources and provides a stable digital trigger signal for downstream circuits. Simple integration: Standard signal pinout and a single digital output make it easy to connect to microcontrollers, relays, and driver circuits. Adjustable behavior: Builtin sensitivity and delay adjustments let you tune detection distance and hold time to match your application and avoid false triggers. Low power and lightweight: Designed for battery or DCpowered projects where low current draw and small size matter. Durable sensing element: Uses a pyroelectric infrared sensor with a molded Fresnel lens to focus infrared energy for consistent response. Main features Motion detection function: Outputs a digital or low when motion is detected, suitable as a trigger for alarms, lights, or automation routines. Adjustable sensitivity: Fine tuning lets you limit detection to closer motion or extend range as needed. Adjustable delay time: Set how long the output stays active after detection, from short pulses to longer hold times. Compact module: Small PCB profile and mounting options allow installation in constrained spaces or enclosures. Standard interface: Threepin or header connection for easy wiring to controllers and power supplies. Compatible with common microcontroller platforms such as Arduino and Raspberry Pi for prototype and production use. Performance and materials Sensor type: Pyroelectric infrared sensor coupled with a Fresnel lens for directional detection and stable performance. Construction: Printed circuit board module with plastic lens assembly designed for typical indoor and sheltered outdoor installations. Output type: Clean digital trigger signal compatible with typical logic voltage levels used in microcontroller systems. Power requirements: Designed for lowvoltage DC operation suitable for battery and DC supply applications. Practical use scenarios Motionactivated lighting: Turn on corridor or closet lighting only when a person is present to improve convenience and reduce energy use. Security and alarm systems: Use as a trigger input for intrusion detection, logging, or alert systems. Smart automation: Integrate into home automation tasks such as waking a controller, activating cameras, or initiating HVAC adjustments when occupancy is detected. Why choose this module The HCSR501 module provides a straightforward, reliable way to add human motion detection to electronic projects and systems. Its adjustable settings and standard digital output simplify tuning and integration, while the compact form factor and low power design make it suitable for a wide range of practical applications.