HCSR501 Infrared PIR Motion Sensor Module for Arduino and Raspberry pi Why this module is useful Detects human and animal motion reliably to automate lighting, alerts, and data collection. Lowpower standby and simple digital output make it easy to integrate into battery or mains projects. Compact, readytouse module with onboard adjustments avoids the need for complex signal processing. Key benefits and problem solving Quick integration: Provides a clean digital signal when motion is detected, so you can connect directly to microcontroller input pins without extra circuitry. behavior: Adjustable sensitivity and delay let you tune detection distance and how long the output stays active, reducing false triggers and unnecessary actions. Flexible power and trigger options: Wide supply range and selectable trigger mode support diverse applications from simple hobby projects to fixed installations. Main features and specifications Function: Passive infrared motion detection with digital output that switches when motion is detected. Compatibility: Works with common development boards including Arduino and Raspberry pi. Power: Typical operating voltage range 4.5 to 20 V DC, commonly used at 5 V. Detection: Typical detection range up to about 7 meters and detection angle around 120 degrees. Adjustments: Onboard potentiometers for sensitivity and output hold time; jumper for retriggering mode selection. Size and construction: Compact PCB module with Fresnel PIR lens for directional sensing; suitable for breadboard or enclosure mounting. Performance: Low standby current and stable digital output suitable for GPIO inputs. Practical use scenarios Automatic lighting: Turn corridor or closet lights on only when someone enters, then switch off after a set delay to save energy. Security and alarm systems: Trigger cameras, alarms, or logging events when motion is detected in a monitored area. DIY electronics and robotics: Add presence sensing to robots, interactive installations, or occupancy counters for responsive behavior. What to expect in integration Direct connection to a digital input with power and ground plus output pin. Simple tuning by adjusting sensitivity and delay while testing in the intended environment. Reliable operation when mounted with clear line of sight and minimal airflow interference. This module provides a practical, adjustable motion sensing solution for prototyping and installations that require straightforward motion detection and easy compatibility with common microcontroller platforms.