Bluetooth wireless communication technology has become very popular and it is one of the fastest-growing fields in wireless technology. Nowadays, demands of mobile phones and personal communication the bandwidth is easy and convenient to use. The Bluetooth technology manages the communication channel of the wireless part. Based on the current market and the development trend of the Internet of Things in the future, versions of Bluetooth technology is classified into 2 types: classic and low-energy (LE). The classic Bluetooth assures the data transmission rate so that it is suitable for applications such as the Bluetooth headset transmitting high-quality music. In the classic type, it is subdivided into the basic rate (BR) and the enhanced data rate (EDR). The low-energy Bluetooth focuses more on the simple information transmission, which tries to extend the endurance time of electronics as long as possible.
The Bluetooth modules can transmit and receives the data wirelessly by using two devices. The Bluetooth module can receive and transmits the data from a host system with the help of the host controller interface (HCI). The UART & USB are the most popular host controller interfaces and in this article, we have discussed the UART. By using the UART connections, the Bluetooth module can be integrated and it gives the best possible solutions for the Bluetooth embedded systems.
How to Select a Bluetooth Module
The Bluetooth module is a functional component and can only function completely when embedded into a proper system. When you select a Bluetooth module for your product, further consideration should be taken into hardware and software. The hardware of a Bluetooth module consists of a Bluetooth chip and an application processor. Most products currently on the market are embedded with Bluetooth modules equipped with application processors. The application processor in the module has internal or external flash memory, ROM and RAM. This kind of module also provides different I/O interfaces, including the time clock, serial communication interface, analog comparator, ADC, DAC, crystal oscillator and the debugging interface, etc.
RN4677 Bluetooth 4.0 module
The Microchip RN4677 Bluetooth 4.0 module is a Smart Ready device able to communicate with other devices operating under Bluetooth Classic or BLE protocols. Programmed for IoT applications, it contains profiles for communication with Apple and Android Smart Phones in Bluetooth Classic (Master) and Low Energy (Central)roles.
Microchip RN4677 Certified Bluetooth Dual Mode module supports both Bluetooth Classic and Bluetooth Low Energy (BLE) communication. Under Bluetooth Classic, RN4677 implements standard Serial Port Profile (SPP) that supports serial data transfer between two Bluetooth Classic devices. In addition to SPP for Bluetooth Classic connectivity, the RN4677 introduces a private Generic Attribute Profile (GATT) service for serial data transfer between two BLE devices.
HC‐05 Bluetooth module:-
HC‐05 module is an easy to use Bluetooth SPP (Serial Port Protocol) module, designed for transparent wireless serial connection setup. The HC-05Bluetooth Module can be used in a Master or Slave configuration, making it a great solution for wireless communication. This serial port Bluetooth module is fully qualified Bluetooth V2.0+EDR (Enhanced Data Rate) 3Mbps Modulation with complete 2.4GHz radio transceiver and baseband. It uses a CSR Bluecore 04 External single-chip Bluetooth system with CMOS technology and with AFH (Adaptive Frequency Hopping Feature).
Hardware Features:-
Typical ‐80dBm sensitivity.
Up to +4dBm RF transmit power.
3.3 to 5 V I/O.
PIO (Programmable Input/Output) control.
UART interface with programmable baud rate.
With integrated antenna.
With edge connector.
Software Features:-
Slave default Baud rate: 9600, Data bits: 8, Stop bit: 1, Parity: No parity.
Auto‐connect to the last device on power as default.
Permit pairing device to connect as default.
Auto‐pairing PINCODE:”1234” as default.
HM-06 Bluetooth module
HM-06 is a Bluetooth module designed for establishing short-range wireless data communication between two microcontrollers or systems. The module works on Bluetooth 2.0 communication protocol and it can only act as a slave device. This is the cheapest method for wireless data transmission. It is more flexible compared to other methods and it even can transmit files at speed up to 2.1Mb/s.
HM-10 Bluetooth Module
The HM-10 is a readily available Bluetooth 4.0 module. This module is used for establishing wireless data communication. The module is designed by using the Texas Instruments CC2540 or CC2541 Bluetooth low energy (BLE) System on Chip (SoC). This Module is used where short-distance wireless communication is needed. The module is used for wireless communications of less than 100 meters. The module is preferred where power consumption is an issue. HM-10 module is designed by BLE chip so it consumes very little power to function.
