The Devore sensor array was an automated sensor drone used by the Devore Imperium in the late 24th century.
The sensor array emitted a scanning pulse every forty seconds over a range of ten light years. A pulse was designed to track warp fields and impulse signatures. It was possible for a starship to lower its power output below the detection threshold of an array.
In 2375, the USS Voyager attempted to silently pass a sensor array on its route to the Tehara star system; however, the attempt failed and the array transmitted an alert, which was received by two Devore warships. (VOY: "Counterpoint")
According to tbe script, this sensor array is "a vast platform pierced by a spire-like central tower and supporting a series of domes - reactor housings, all PULSING with LIGHT and SOUND."