How Does Bluetooth Actually Work?

Morning Blueteeth!

Fun fact:

The name Bluetooth comes from the Viking king Harald Bluetooth.

Called so because of his supposedly dead tooth that was blue…

Also, the logo for Bluetooth came from the initials of Harald Bluetooth in Nordic Runes:

Pretty cool, right?

Speaking of Bluetooth… what actually is it?

Some magic signal that flows through the air?

Kinda… Bluetooth is basically light.

But not like the light of a torch…

You’ve probably seen this before: The electromagnetic spectrum.

A chart that consists of all the different wavelengths of light.

See that tiny little rainbow bit? 

That is literally ALL THE LIGHT WE CAN SEE.

Relative to how many wavelengths of light there are, we're kinda blind.

Anyway, Bluetooth light is way over here:

This stuff can travel through walls, like our light can travel through glass.

Pretty cool.

But how does this light allow us to listen to Taylor Swift through the air?

The answer: 1s and 0s

Your phone encodes an entire song in the form of a REALLY long string of digits like this: 

Now, say your phone wants to wirelessly transmit this signal to your headphones.

How does it do it?

It uses that light stuff from earlier!

Remember how light comes in different wavelengths?

Well, when your phone wants to transmit a 1, it will flash a wavelength of 121 mm.

And when it wants to transmit a 0, it will flash a wavelength of 124 mm.

These specific wavelengths are then picked up by your headphones and decoded back into 1s and 0s.

Then they are decoded again into T-Swift songs.

Or whatever you secret Swifties listen to…

Alright, but what if your buddy is sitting next to you also with Bluetooth on?

How do your headphones know what signal to use then?

Well, this is where keys come in.

When you pair 2 devices together, your headphones will send out a little password key through their antenna to your phone.

When you click to pair the device, the phone sends the password key back to the headphones.

Then, when you wanna listen to some tunes, your headphones will change their password and send both the old and new passwords to your phone.

Then your phone uses this new password to transmit those 1s and 0s to your headphones.

This continues back and forth, changing password keys every time… and tada!

Now you can listen to your music, and your buddy can listen to his.

Wirelessly.

Stay Cute,
Reece, Henry & Dylan 🌈

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