HC-SR501 PIR Motion Sensor with Adjustable Sensitivity & Delay

The HC-SR501 PIR Motion Sensor is a passive infrared module designed to detect human motion by sensing changes in infrared radiation. It provides a digital output of 3.3 V (high) and 0 V (low), with an adjustable sensitivity up to a 6 m sensing distance and a detection angle of 110°. The module operates within a wide voltage range of 4.5–20 V and features adjustable output delay of approximately 2–4 seconds. With a low quiescent current of 50 µA and compact 32 × 24 mm dimensions, it is suitable for low-power electronic systems. Typical applications include security systems, automatic lighting, occupancy detection, and microcontroller-based projects.