There's a longer story you can read elsewhere, but actress Hedy Lamarr invented and patented a system to help prevent torpedoes from being jammed by using frequency hopping.
Neither Hedy or her co-patenter made money from the invention because their patent expired before it was implemented in 1962, and wasn't really acknowledged until 1997 by the EFF. The core logic to the invention is still in use today in spread-spectrum communications like Wi-Fi and CDMA. You can read more about it here. [Divine Caroline]