ELI5: How does Bluetooth work?

Bluetooth works by using invisible radio waves to send information between two nearby devices without any wires.

Imagine you and your best friend want to talk to each other across a living room. Instead of passing a long piece of string between you, you use your voices. Bluetooth does something very similar, but instead of sound, it uses quiet, invisible signals that travel through the air.

Here is how it works in everyday life:

• Saying hello (Pairing): Before two devices can share anything, they need to introduce themselves. When you connect your wireless headphones to a smartphone for the first time, they exchange a secret digital handshake so they recognize each other later.
• Whispering in a crowded room (Short range): Bluetooth signals are designed to be very weak and only reach about thirty feet, or the size of a couple of rooms. Because the signals only travel a short distance, they do not use much battery power, and they do not accidentally connect to your neighbor's devices.
• Hopping between secret channels (Frequency hopping): Imagine a busy playground where many people are talking at once. To avoid getting mixed up with Wi-Fi, microwaves, or other Bluetooth gadgets, your devices constantly change the specific invisible channel they use to talk. They switch these channels hundreds of times every second, staying in perfect sync so the music never stops.

• Your wireless headphones play music sent invisibly from your phone in your pocket.
• A smartwatch tells you that you have a text message because your phone forwarded the alert through the air.
• A wireless mouse tells your computer where to move the arrow on the screen without a cord tangling your desk.