The PIR Motion Sensor Detector Module HC-SR501 allows you to sense motion. It is almost always used to detect the motion of a human body within the sensor’s range. It is often referred to used “PIR”, “Pyroelectric”, “Passive Infrared” and “IR Motion” sensor. The module has an onboard pyroelectric sensor, conditioning circuitry, and a dome-shaped Fresnel lens. It has a delay time adjustment Potentiometer and sensitivity adjustment Potentiometer. Repeat Trigger Selection Jumper is also available. Compatible with ARDUINO, RASPBERRY PI, AVR, PIC, 8051, etc.Features : Infrared Sensor with Control Circuit Board The Sensitivity and Holding Time Can be Adjusted Blockade time: 2.5s (Default) Sensitive Setting: Turn to Right, Distance Increases (About 7M); Turn to Left, Distance Reduce (About 3M) Time Setting: Turn to Right, Time Increases (About 200S); Turn to Left, Time Reduce (About 5S).