Hedy Lamarr co-invented "frequency hopping."

A Mighty Girl

Hedy Lamarr is famous as a glamorous movie star from the black-and-white era of film. But what most people don't know about her is that, in 1942, she co-invented a device that helped make possible the development of GPS, Bluetooth, and Wi-Fi technology!

Born in Austria in 1914, the mathematically talented Lamarr moved to the US in 1937 to start a Hollywood career. Throughout the 1930s and 1940s, she was considered one of cinema's leading ladies and made numerous films; however, her passion for engineering is far less known today. Her interest in inventing was such that she set up an engineering room in her house complete with a drafting table and wall of engineering reference books. With the outbreak of World War II, Lamarr wanted to apply her skills to helping the war effort and, motivated by reports of German U-boats sinking ships in the Atlantic, she began investigating ways to improve torpedo technology.

After Lamar met composer George Antheil, who had been experimenting with automated control of musical instruments, together they hit on the idea of "frequency hopping." At the time, radio-controlled torpedoes could easily be detected and jammed by broadcasting interference at the frequency of the control signal, thereby causing the torpedo to go off course. Frequency hopping essentially served to encrypt the control signal because it was impossible for a target to scan and jam all of the frequencies.
Lamarr and Antheil were granted a patent for their invention on August 11, 1942, but the US Navy wasn't interested in applying their groundbreaking technology until twenty years later when it was used on military ships during a blockade of Cuba in 1962. Lamarr and Antheil's frequency-hopping concept serves as a basis for the spread-spectrum communication technology used in GPS, Wi-Fi and Bluetooth devices.