HCSR501 PIR motion sensor module compact, lowpower passive infrared detector for automatic presence sensing and simple integration. Key benefits Low quiescent current for batterypowered projects. Ideal when long standby times are required. Wide supply range for flexible use across DC 5V to 20V systems. Clear digital output compatible with microcontrollers and logic inputs: at 3.3V, low at 0V. Adjustable timing and trigger behavior to match different applications and reduce false activations. Simple threepin interface and jumper configuration for quick installation and testing. Main features Supply voltage: DC 5V to 20V. Quiescent current: 65 (typical). Output level: 3.3V, low 0V. Delay time: adjustable from 0.3 seconds to 18 seconds. Induction blackout time (retrigger suppression): default 0.2 seconds. Trigger modes: H = retriggerable (default), L = nonretriggerable. Detection angle: less than 120 degree cone. Detection distance: up to 7 meters depending on mounting and environment. Operating temperature range: 15 to 70 C. PCB dimensions: 32 x 24 mm. Mounting hole center distance 28 mm, hole diameter 2 mm. PIR lens diameter: 23 mm by default. Photoresistor light control optional: factory module does not include photoresistor. Photoresistor can be added on request to enable lightdependent switching. Connector and jumper layout Pin 1: VCC (power supply). Pin 2: OUT (/low level output). Pin 3: GND (power negative). H jumper: retriggerable mode. L jumper: nonretriggerable mode. CDS pad: optional photoresistor connection for light control. Behavior modes explained Nonretriggerable mode (L): after output goes and the selected delay elapses, output returns automatically to low. Retriggerable mode (H, default): if motion is detected again during the delay interval, the output is extended; the output only returns to low after motion has left the detection area and the delay period has completed. Induction blackout time: after each detection the output may switch; during the configured blackout interval the sensor will ignore signals. This reduces false triggers and prevents rapid switching of loads. Installation and use notes Allow about one minute after powerup for the module to initialize. During initial warmup the module may produce 0 to 3 output pulses; normal operation resumes after about one minute. Avoid direct bright sunlight on the PIR lens and strong nearby lighting that can introduce interference. Minimize airflow over the lens to reduce false triggers from moving curtains or plants. For sensitivity mount the sensor so human movement crosses the sensor field of view laterally rather than directly toward or away from the module. The PIR uses dual elements; sidetoside motion produces larger differential signal and better detection. Mount the module with its long axis parallel to expected motion paths. To use light control function the module with the photoresistor installed and configure the CDS pad. If photoresistor is not installed, the module ignores ambient light level. Typical applications Automatic lighting for corridors, stairways, closets, and utility rooms where motionactivated on demand lighting improves convenience and saves energy. Security and motion detection for alarms, cameras, and automation triggers in home or small commercial systems. Batterypowered sensing projects and embedded systems where low standby current and wide supply voltage simplify design. Package and condition Type: Module. Condition: . Package: SMD. : Photoresistor optional on request. This HCSR501 module provides straightforward motion detection with adjustable timing, selectable trigger mode, and a wide supply range for flexible integration into lighting, security, and automation projects.