How do Bluetooth devices work?
The science behind the hands free magic
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.