Bluetooth

  Bluetooth

Introduction & History:

Bluetooth is a device which exchange data over short distance from fixed and mobile. It uses Ultra high frequency radio waves in the ISM band from 2.4 to 2.485 GHz. It is basically used in mobile devices, laptops, tabs, portable devices etc. It built personal area networks (Pans). It can connect several devices to overcome problem of synchronization. It is invented in 2004 by Ericsson. Bluetooth is managed by Bluetooth Special Interest Group Bluetooth is now used in different devices made by different organizations. These organizations must be either promoter member or associate with Bluetooth SIG before they access Bluetooth specifications. The SIG owns Bluetooth word mark, figure mark and combination mark. These trademarks are licensed out for use to Companies that are incorporating Bluetooth wireless technology into their products. The main tasks for the SIG are to publish the Bluetooth specifications, protect the Bluetooth trademarks and evangelize Bluetooth wireless technology.

Implementation:

Bluetooth operates at frequencies between 2.4 and 2.485 GHz including guard bands of 2 MHz at the bottom end and 3.5 MHz at the top. This is globally unlicensed Industrial Scientific and Medical 2.4 GHz short-range radio frequency band. Bluetooth uses a radio technology called frequency hopping spread spectrum. Bluetooth divides transmitted data into packets, and transmits each packet on one of 79 designated Bluetooth channels. Each channel has a bandwidth of 1 MHz Bluetooth 4.0 uses 2 MHz spacing, which accommodate 40 channels. The first channel starts at 2402 MHz and continues up to 2480 MHz in 1 MHz steps. It usually performs 1600 hops per second, with Adaptive Frequency-Hopping enabled. Originally, Gaussian frequency-shift keying modulation was the only modulation scheme available. Since the introduction of Bluetooth 2.0+EDR, π/4-DQPSK and 8DPSK modulation may also be used between compatible devices. Devices functioning with GFSK are said to be operating in basic rate mode where an instantaneous data rate of 1 Mbit/s is possible. The term Enhanced Data Rate is used to explain π/4-DPSK and 8DPSK schemes, each giving 2 and 3 Mbit/s respectively. The grouping of these modes in Bluetooth radio technology is classified as a "BR/EDR radio".

Applications:

Wireless controlled of and communication among a mobile phone and a hands free headset. This was one of the earliest applications to become popular. Wireless controlled of and communication between a mobile phone and a Bluetooth compatible car stereo system. Wireless controlled of and communication with tablets and speakers such as IOS and Android devices. Wireless Bluetooth head set and Intercom. A headset is occasionally called "a Bluetooth". Wireless stream of audio to head phones with or without communication capabilities. Wireless networking between PCs in a confined space and where little bandwidth is required.

HC-06 Bluetooth Module:

HC serial Bluetooth products consist of Bluetooth serial interface module and Bluetooth adapter. Bluetooth serial module is used for converting serial port to Bluetooth. These modules have two modes: master and slaver device. The device named after even number is defined to be master or slaver when out of factory and can’t be changed to the other mode. But for the device named after odd number, users can set the work mode (master or slaver) of the device by AT commands.

1. Technical data:

•Chipset: CSR 

•Bluetooth V2.0 

•Working voltage: 3.3V 

•Current: pairing 20~30mA, connected 8mA 

•Dimensions: 1.06 in x 0.51 in x 0.04 in 

•Dimensions: 2.7 cm x 1.3 cm x 0.1 cm 

• Default baud rate: 9600

•Weight: 0.18 oz (5 g)

Figure 3.11