How do Bluetooth devices work?

The science behind the hands free magic

April 18, 2016
Using a hands-free Bluetooth earpiece can make you feel like you are really living in the future—but how do they work? [Image credit: Pixabay User Esa Riutta, CC0 Public Domain]

Bluetooth technology is everywhere — in our cars, our homes, our laptops, even our ears. So how does it work?

Bluetooth uses radio waves instead of wires or cables to transmit information between electronic devices over short-distances. Unlike your cellphone, which uses radio waves to communicate with a cell tower several miles away, the radio waves Bluetooth products use are 1000 times weaker and only travel small distances between the two communicating devices, usually 10 feet or less. If you have a wireless Bluetooth keyboard for your computer, and you take the keyboard to a friend’s house but leave the computer at home, your keyboard won’t be able to communicate with the computer over such a distance. And if you type on it, nothing will appear on your computer screen at home.

When Bluetooth-enabled devices are close enough, they can connect with each other through a tiny computer chip inside them that emits the special Bluetooth radio waves. But first, you have to turn on this chip, which you can usually do by pressing a specific button or flipping a marked switch. Then, the communication between the two Bluetooth devices happens over a short-range network called a piconet (pico means really really small in the metric system). This piconet is essentially a network of Bluetooth connected devices. If you’ve connected your computer to a Bluetooth-enabled keyboard, monitor, mouse and speakers, all these devices will form their own Bluetooth piconet. But they won’t be talking to each other individually. One device — in this case the computer — will be the main device with which all the others are connected.

Piconets are established automatically. So once you have a device, like your keyboard, installed and in range of the piconet, it will automatically connect. But if it is not in range the keyboard will automatically leave the piconet. When you bring the keyboard back home, where it is in range again, it will automatically reconnect.

It isn’t hard to see why Bluetooth technology has become so popular in recent years. Now everyone can feel like Lieutenant Uhura in the original Star Trek television series as they press their finger to their ear and activate their Bluetooth earpiece in order to receive an incoming phone call, leaving their hands free to help save the starship Enterprise — or drive a car.

About the Author

Jeanette Ferrara

Jeanette Ferrara hails from the outskirts of Houston, Texas. She is a recent graduate of Princeton University, where she majored in English literature with a concentration in Environmental Studies. At SHERP, she covered the medical beat and discovered a passion for data journalism and writing for children.



N T Parry says:

Please advise, do Bl;uetooth charge for using the system, or are the charges only made by the owners of the various of the advertising companies. Your reply would be appreciated.

Rebecca Sohn says:

Hi N T! Thank you for reading this article. Based on a quick examination of Bluetooth’s website, it seems that companies need to apply to be “member” companies of Bluetooth in order to obtain a license to use Bluetooth in their products. Depending on the kind of membership, this could cost the company money. Of course, the company would also need to pay to obtain Bluetooth components and manufacture the technology in their products. Consumers buying Bluetooth products might pay more to mitigate both of these costs. To my knowledge, using Bluetooth does not cost consumers money after purchase, unless you are using mobile data for internet access through Bluetooth. I hope this answers your question. – Rebecca Sohn, Associate Editor, Scienceline

N T Parry says:

Dear Rebecca, Thank you very much indeed for taking the time to answer my question, Regards Trevor Parry

Ubaldo Tengfah says:

Thanks for your help.I’ve learned a lot from your explanation.

Ubaldo Tengfah Felix says:


VP Taneja says:

Really you helped I never new about piconet
Thanks dear

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