Whenever you use your cellphone, Wi-Fi or a Bluetooth headset, you have actress Hedy Lamarr to thank.


Lamarr, born Hedwig Eva Maria Kiesler in Vienna in 1913, starred in classic films such as "Samson and Delilah" (1949), "Boom Town" (1940), "The Conspirators" (1944) and the Czechoslovakian film "Ecstasy" (1933), in which she famously became the first actress to simulate an orgasm on film.


But Lamarr's greatest long-term contribution to society was not as an actress but as an inventor. She and composer George Antheil co-invented early techniques for spread-spectrum communications and frequency hopping, technologies that were used for military communication for decades and which now form the core of many of today's most popular wireless devices.


The story of Lamarr, who had been keenly interested in science as a child, is detailed in the new book "Hedy's Folly: The Life and Breakthrough Inventions of Hedy Lamarr, the Most Beautiful Woman in the World" by Richard Rhodes, released this week by Doubleday.


Lamarr saw the danger of the rise of the Nazi party while married to her first husband, Austrian arms manufacturer Friedrich Mandle, in the 1930s. She escaped that marriage and moved to California where she became a Hollywood star and began her practice of inventing things during the long wait between shots.


"Hedy invented as a hobby," Rhodes writes in his book. "Since she made two or three movies a year, each one taking a month to shoot, she had spare time to fill. She didn't drink and she didn't like to party, so she took up inventing." She set up a drafting table to form an "inventor's corner" in her Hollywood home. Among her many projects was an improved stoplight, according to NPR. 


This creative inspiration was well-timed — it dovetailed with the launch of the National Inventors Council, a place to gather novel ideas and inventions from the general public, according to Inventions.org


Few of her ideas moved to fruition, but in 1940, the sinking of a cruise ship by Nazi U-boats inspired her to action. She came up with the idea of a radio signal that would "hop around from radio frequency to radio frequency," which would prevent it from being jammed, allowing torpedoes to be safely guided by radio from nearby airplanes, Rhodes recently told NPR


Lamarr and Antheil worked on their idea for several months and then, in December 1940, sent a description of it to the inventors council. They were granted a patent for their "secret communication system" on Aug. 11, 1942. They gave the patent at no cost to the U.S. Navy, but the military sat on the idea and did not implement it until the 1960s, long after the patent had expired.


The secret communication system was not Lamarr's only contribution to the war effort. She also raised more than $25 million by promoting the sale of war bonds.


Lamarr and Antheil never profited from the invention, but it went on to become the core technology behind Wi-Fi networks and CDMA, or Code Division Multiple Access, cellphones. "The whole system spread like wildfire," Rhodes told NPR. "The most well-known application today is Bluetooth." All the while, the public has remained virtually ignorant of her contribution.


The Electronic Frontier Foundation gave Lamarr its Pioneer Award in 1997 for her role in creating spread-spectrum technology. The actress died in Florida in 2000.


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