# eli5 How do radio waves work through controllers?

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Example: I have a remote controlled device, like a plane. I use the controller to tell thenplane to thrust, it thrusts. I use the controller to turn the plane, it turns. How can radio waves be used to control a device?

In: Engineering

Just to confirm, are you asking how the radio waves can be used to control the plane?

Remote control toys work by broadcasting a signal from the controller that can be received or “heard” by the remotely controlled device. You can imagine this as if your controller was making a series of beeps when you input a command. You push the thrust up button, the controller makes the radio wave version of a “beep beep beep” through it’s antenna. The remote control device then “hears” the “beep beep beep” command through its own antenna and recognizes that as the “thrust up command”.

I’m not sure with your question but you may be asking how the controller transmits radio waves through its plastic casing. It can do that because in the same way glass is translucent to light most kinds of plastic are translucent to radio waves.

Radio is an EM wave. Like light. I’d say it is light but then some smart ass is gonna try to tell me light is only what we call the visible spectrum.

Anyways, radio is like light we can’t see. So imagine you’re the drone or plane or whatever. You get instructions from a flashing light you see. Let’s say it’s telling you to thrust in Morse code, then you thrust. Et cetera et cetera.

Except it’s not Morse code, it’s binary and light on is 1 and 0 is light off. And it’s also much much much faster than Morse code. A robot or circuit can detect flashes at extremely small intervals of time. The robot then decides the 1s and 0s with software and interprets chunks of 1s and 0s as an instruction.

You might think like, “but how does the controller know where the plane is in order to send the signal?” It doesn’t have to. When the light is emitted it travels in all directions. That’s why if it were visible, you’d be able to see the light anywhere you stand.

Same thing happens with IR and tv controllers and Bluetooth and all those wireless things.