Stemedu 3PCS HC-SR501 PIR Human Body Motion Sensors, Infrared IR Motion-Activated Switch, Distance Detector Sensor Module for Indoor Stairs Corridor Night Light (Pack of 3pcs) Stemedu 31 ratings ...

HC-SR501 Delay Time: 0.5-200S (adjustable), the range is (0.xx second to tens of second), the delay time can be adjusted by using the potentiometer on the HC-SR501 motion sensor.

But to prevent any wet and angry pedestrians, a HC-SR501 PIR motion sensor is used. If the system sees motion it will stop for a while to let the activity quiet down.