Most remote controls rely on low-frequency light waves to send out signals. Since the early 1980′s, remote controls have generally used light in the infrared range, which has such a low frequency that your eyes can’t see it. The remote control sends a different flashing light message, like Morse code, for each job you want done.

You press a button on your remote control. That push tells a tiny computer processor to trigger a light-emitting device called a “diode” at the front of the remote. The diode then flashes an infrared signal to a light-sensitive area – called a “photocell” – on your TV. The signal is different depending on which button you push – say, the volume control or the channel-changer. To make sure your TV gets the message, these light signals are repeated five times a second. Nowadays, some remote controls can handle as many as fifty different commands. Now if only you could remember where you left it!