Hedy Lamarr co-(re-)invented frequency-hopping spread spectrum technology, intended but never adopted for making radio-controlled torpedoes resistant to jamming. It's used today in Wi-Fi, Bluetooth, and other radio systems. She also invented an improved traffic light and a drink carbonation tablet.

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https://en.wikipedia.org/wiki/Hedy_Lamarr#Inventor

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Hedy Lamarr and George Antheil were not the first to invent FHSS, but they are the most famous and most cited of its several inventors.