Â­TÂ­here are many different ways to create a motion sensor. For example: 1  It is common for stores to have a beam of light crossing the room near the door, and a photosensor on the other side of the Â­room. 2  When a customer breaks the beam, the photosensor detects the change in the amount of light and rings a bell.
Effluent is an outflowing of water or gas from a natural body of water, or from a manmade structure. Effluent, in engineering, is the stream exiting a chemical reactor. Effluent is defined by the United States Environmental Protection Agency as wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters.
Full Definition of WEIR. 1. : a fence or enclosure set in a waterway for taking fish. 2. : a dam in a stream or river to raise the water level or divert its flow. See weir defined for English-language learners. See weir defined for kids.