KAREN GRIGSBY BATES: Here's something you might not have known about World War II. One of the most popular Hollywood actresses of the era was also developing weapons systems for the U.S. Navy. Today would've been the 100th birthday of a true Renaissance woman, Hedy Lamarr.
(SOUNDBITE OF FILM, "ECSTASY")
HEDY LAMARR: (As Eva Hermann) I was doing what I wanted to do - playing my own way and making my own rules.
GRIGSBY BATES: Hedy Lamarr biographer Richard Rhodes said, her acting career started when she was still a teenage schoolgirl in Austria.
RICHARD RHODES: Hedy's first starring was in a film called "Ecstasy," which was notorious because it involved full frontal nudity and simulated sex.
GRIGSBY BATES: Rhodes says, many sources get the year of her birth wrong because she told the studio she was born in 1913, not '14. Unlike many actresses, she made herself older.
RHODES: In order to play this role, she had to be at least 16 years old. And in order to make that happen, she had to lie about her age 'cause she wasn't.
GRIGSBY BATES: After her scandalous turn in "Ecstasy," she moved to Hollywood and signed a contract with MGM. They began promoting her as the most beautiful woman in the world. She hated that her image got top billing over her mind.
RHODES: You know, it frustrated her, terribly. She'd like to say, my beauty is my curse.
(SOUNDBITE OF FILM, "ECSTASY")
UNIDENTIFIED ACTOR: You know, you're a very lovely girl.
LAMARR: (As Eva Hermann) You're not being very scientific, doctor.
KAREN GRIGSBY BATES, HOST:
She avoided the wild Hollywood lifestyle, often retreating into a life of the mind at home.
RHODES: She had a drafting table installed and architects lamps. And there was an entire wall of technical manuals of various kinds for references. And she would sit at her drafting table and invent things.
GRIGSBY BATES: In 1940, she found inspiration. Lamarr read about the deadly accuracy of German submarines. British and American naval technology was no match at the time.
RHODES: So she focused on a particular problem, which was we had lousy torpedoes.
GRIGSBY BATES: Their guidance systems were routinely inaccurate. Hedy Lamarr imagined using radio frequencies to allow the submarine to talk to the torpedo, to guide it remotely.
RHODES: The problem she focused on almost immediately was what if a German ship tried to jam the radio signal?
GRIGSBY BATES: To solve that problem, she was inspired by a relatively new invention - the remote control on the radio in her living room. You clicked a button across the room, and the radio changed frequencies. If she could figure out how to allow the submarine and the torpedo to keep talking to each other while constantly changing frequencies, the Germans couldn't jam their signal.
RHODES: And at that point, she was at a dinner party. And one of her fellow guests was a curious American avant-garde composer named George Antheil.
(SOUNDBITE OF SONG, "BALLET MECANIQUE")
GRIGSBY BATES: Antheil famously wrote this piece, "Ballet Mecanique." The score called for 16 synchronized player pianos - you know, the players with the big scrolls of dotted paper inside. The pianos would automatically play the notes that corresponded with the holes that had been punched into the paper. Antheil figured that same technology could solve Lamarr's problem. If you could scale this down to something tiny and get both the submarine and the torpedo to start their scrolls simultaneously...
RHODES: ...The two could work in sync and jump from frequency to frequency. That's why Hedy called it frequency hopping.
GRIGSBY BATES: Hedy Lamarr and George Antheil patented their invention and donated the patent to the U.S. Navy. The Navy brass was not impressed.
RHODES: They said, what do you want to do - put a player piano in a torpedo? Get out of here.
(SOUNDBITE OF SONG, "BALLET MECANIQUE")
GRIGSBY BATES: But long after their invention was shelved and forgotten, it found new life. What Hedy Lamarr called frequency hopping sparked the idea for spread-spectrum technology.
RHODES: It found application in car telephones. Bluetooth still uses frequency hopping. Military systems that went commercial, such as GPS, use frequency hopping for the uplink-downlink to GPS systems.
GRIGSBY BATES: Yup. That's right. You wouldn't have GPS or Bluetooth had it not been for Hedy Lamarr.
(SOUNDBITE OF ORCHESTRAL MUSIC)
GRIGSBY BATES: In 1960, she received a star on the Hollywood Walk of Fame. It wasn't until this year - her 100th birthday - that Hedy Lamarr would be inducted into the National Inventors Hall of Fame. Richard Rhodes' biography of Hedy Lamarr came out in 2011. It's called "Hedy's Folly." Transcript provided by NPR, Copyright NPR.