SR501 HCSR501 Adjustable PIR Motion Sensor Module A compact, easy to integrate passive infrared motion sensor module that detects human or animal movement and provides a reliable digital trigger output. The module uses a pyroelectric infrared sensor with a Fresnel lens and onboard adjustments for sensitivity and trigger duration, making it practical for a wide range of automation and detection projects. Key benefits Detects motion reliably and provides a clear digital output for controllers and circuits. Ideal for adding motion awareness to projects without complex signal processing. Adjustable sensitivity and time delay let you tune detection range and how long the output stays active after motion is detected. This reduces false triggers and adapts performance to the installation environment. Compact module and standard pinout make it simple to connect to microcontrollers and controllers for fast prototyping and deployment. Low power consumption and passive detection help conserve energy compared to continuously active sensors. Important attributes Function: Passive infrared motion detection with digital trigger output and adjustable sensitivity and delay controls. Compatibility: Designed for easy use with common microcontrollers and development boards such as Arduino and Raspberry Pi and with alarm and lighting control circuits. Size and form: Small PCB module with a Fresnel lens; fits into enclosures or projects where space is limited. Material: PCB with an integrated Fresnel plastic lens and standard electronic components for straightforward mounting and wiring. Performance: Tunable detection behavior allows adaptation to different environments and target distances; suitable for indoor installations and many outdoor covered locations. Typical applications Automatic lighting control: Turn lights on when someone enters a room and off after a configurable delay to save energy and improve convenience. Security and alarm systems: Trigger an alarm input or wake a monitoring circuit when motion is detected in a monitored area. DIY electronics and automation: Add presence sensing to robotics, occupancy counters, smart home devices, and interactive installations. Practical notes The module provides a digital output that is simple to read with most microcontrollers. Adjust the sensitivity and delay knobs to match the intended range and response time for your installation. Place the sensor with a clear line of sight for performance and avoid directing it toward heat sources or drafts that can cause false triggers. The small footprint and standard connection pins allow for straightforward mounting, wiring, and replacement in custom enclosures or prototype boards. This SR501 HCSR501 PIR motion sensor module offers a practical, adjustable solution for adding motion detection capabilities to automation, security, and DIY projects.