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True or false? The number of radio wavelengths emitted per second is called the frequency.
Leon is playing a multiplayer game on his tablet. So as not to disturb Lina, he’s using headphones. There are no cables between the headphones and the tablet. How does the sound reach the headphones? - My name is Harald Bluetooth and ... - What are you doing here? This isn’t a story about vikings. - Are you the one who makes my headphones talk to my tablet? - No, Harald didn’t actually do that.
The headphones and the tablet each have an antenna that transmits and receives signals in the form of radio waves. The radio waves carry information about the sound from the tablet to the headphones. The number of radio waves per second is called frequency. The tablet uses frequencies between 2.4 Gigahertz and 2.4835 Gigahertz. These are frequencies in the same range that WiFi networks use.
But this is not WiFi. Leon wouldn’t be able to use his headphones for very long if he used WiFi. The battery would run out too quickly. Leon's headphones use a different technology, with lower signal strength. This uses less battery power than a WiFi network, but can’t transmit as far.
So when Leon goes to get a drink, there’s no sound in the headphones. The signals from the tablet don’t reach. Leon needs to move closer again, so that the signals can reach. This technology is called Bluetooth, named after that Viking Harald Bluetooth. His initials H and B in Viking script - runes - have given the technology its trademark, its logo.
Those who developed the technology found that Bluetooth was a good name because: - I unified Denmark and Norway. I am very good at making people talk to each other. - Yes, and the technology is designed to enable devices to be able to talk to each other over short distances. When Leon connects his tablet with the headphones, he first must turn on Bluetooth on both devices. When he does, the tablet asks if his headphones should be connected, be paired, with itself. The first time Leon connects the tablet with the headphones, he must enter a four-digit code.
He writes the code for his headphones: six, one, seven, four. But next time, the tablet will remember that it had been paired with his headphones previously. So no code is needed. Bluetooth connects devices in small networks, pico networks. One of the devices in a pico network must be the master.
In this case, the tablet is the master. The other devices do not decide about whether to connect or not. They are called slaves. The slaves can not talk directly to each other, but must always communicate via the pico network master. Leon's headphones are slaves in his pico network.
WIFi and Bluetooth use the same frequencies. If Leon uses both Bluetooth and WiFi at the same time, the signals may interfere with each other. So that this doesn’t happen, the frequencies change slightly all the time. WiFi and Bluetooth jump around between 2.4 and 2.4835 Gigahertz in different patterns from each other. Then the signals do not interfere.
This is called frequency jumping. Thanks to frequency jumping, Leon and his friends can have several pico networks in the same room without interfering with each other. Bluetooth has made it easier for tablets, mobile phones, headphones and smart clocks to talk to each other. - Thanks to me! - Thank you Harald Bluetooth!