In 1885 Edison patented a method to transmit telegraphic "aerial" signals, which worked over short distances, and later sold this "wireless" patent to Guglielmo Marconi.

The vast West Orange, New Jersey, factory, which Edison directed from 1887 to 1931, was the world's most complete research laboratory, an antecedent of modern research and development laboratories, with teams of workers systematically investigating problems. Various inventions included a method to make plate glass, a magnetic ore separator, compressing dies, composition brick, a cement process, an all-concrete house, an electric locomotive (patented 1893), a fluoroscope, a nickel-iron battery, and motion pictures. Edison refused to patent the fluoroscope, so that doctors could use it freely; but he patented the first fluorescent lamp in 1896.

The Edison battery, finally perfected in 1910, was a superior storage battery with an alkaline electrolyte. After 8000 trials Edison remarked, "Well, at least we know 8000 things that don't work." In 1902 he improved the copper oxide battery, which resembled modern dry cells.

Edison's motion picture camera, the kinetograph, could photograph action on 50-foot strips of film, 16 images per foot. A young assistant, in order to make the first Edison movies, in 1893 built a small laboratory called the "Black Maria,"—a shed, painted black inside and out, that revolved on a base to follow the sun and kept the actors illuminated. The kinetoscope projector of 1893 showed the films. The first commercial movie theater, a peepshow, opened in New York in 1884. A coin put into a slot activated the kinetoscope inside the box. Acquiring and improving the projector of Thomas Armat in 1895, Edison marketed it as the Vitascope.

The Edison Company produced over 1,700 movies. Synchronizing movies with the phonograph in 1904, Edison laid the basis for talking pictures. In 1908 his cinemaphone appeared, adjusting film speed to phonograph speed. In 1913 his kinetophone projected talking pictures: the phonograph, behind the screen, was synchronized by ropes and pulleys with the projector. Edison produced several "talkies." Meanwhile, among other inventions, the universal motor, which used alternating or direct current, appeared in 1907; and the electric safety lantern, patented in 1914, greatly reduced casualties among miners. That year Edison invented the telescribe, which combined features of the telephone and dictating phonograph.

During World War I, Edison headed the U.S. Navy Consulting Board and contributed 45 inventions, including substitutes for previously imported chemicals (especially carbolic acid, or phenol), defensive instruments against U-boats, a ship-telephone system, an underwater searchlight, smoke screen machines, anti-torpedo nets, turbine projectile heads, collision mats, navigating equipment, and methods of aiming and firing naval guns.