Today, we use remote controls for everything from televisions to car doors to Mars rovers. Learn about the history and technologies behind them (including radio-frequency, ultrasonic, and infrared remotes) in this episode of BrainStuff, based on these articles: https://science.howstuffworks.com/innovation/repurposed-inventions/history-of-remote-control.htm; https://electronics.howstuffworks.com/remote-control.htm