Introduction to Bluetooth

Bluetooth is a short-range wireless communication technology originally conceived by Ericsson in 1994. The goal of Bluetooth is to facilitate transmission and sharing of information over a short distance without cable connections among mobile devices, embedded devices, computer peripherals, and household appliances. Compared with other wireless communication technologies, Bluetooth boasts high security and easy connection.

📚 Further Reading: Why “Bluetooth”?

The word “Bluetooth” dates back more than a millennia to the Danish King Harald Bluetooth. King Harald is credited with the first unification of Scandinavia. Legend has it that King Harald liked blueberries so much that his teeth were stained blue. So he was called Bluetooth. In 1998, Intel, Nokia, Ericsson, and IBM established a Special Interest Group (SIG) called Bluetooth. The word Bluetooth quickly gained popularity and became synonymous with the short-range wireless communication technology.

Bluetooth adopts decentralised network structure, fast frequency hopping, and short packet technology to support point-to-point and point-to-multipoint communication. It works in the 2.4 GHz ISM (Industrial, Scientific, Medical) band, which is commonly used worldwide. Bluetooth technology can be divided into two categories, Bluetooth Classic and Bluetooth Low Energy.

Bluetooth Classic

Bluetooth Classic (BR/EDR) generally refers to modules that support the Bluetooth protocol below version 4.0, and are used for the transmission of large amounts of data such as voice and music. Bluetooth Classic protocols have different profiles of personal area networks for different scenarios. Commonly used profiles are Advanced Audio Distribution Profile (A2DP) for audio communication, Hands-Free Profile/Head-Set Profile (HFP/HSP) for hands-free devices, Serial Port Profile (SPP) for text serial port transparent transmission, and Human Interface Device (HID) for wireless input/output devices.

Bluetooth Low Energy

Bluetooth Low Energy (LE) is a new type of ultra-low power wireless communication technology, designed for low-cost, less complicated wireless body and personal area networks. It is worth mentioning that Bluetooth LE chips can be powered by button cells. Together with microsensors, you can use the chips to build embedded or wearable sensors and applications of sensor networks.

In terms of protocols, Bluetooth 1.1, 1.2, 2.0, 2.1, and 3.0 apply to Bluetooth Classic, Bluetooth 4.0 supports both Bluetooth Classic and Bluetooth LE, and all later versions employ Bluetooth LE.