HC-05 Bluetooth Module

Description

HC-05 is a Bluetooth module which is designed for wireless communication. This module can be used in a master or slave configuration. It is IEEE 802.15.1 standardized protocol, through which one can build wireless Personal Area Network (PAN). It uses frequency-hopping spread spectrum (FHSS) radio technology to send data over the air. HC-05 communicates with the microcontroller using serial port (USART). We can use it for many applications like a wireless headset, game controllers, wireless mouse, wireless keyboard and many more consumer applications.

Features:

• Communication status LED

• This module works on 3.3 V. We can connect 5V supply voltage as well since the module has on board 5 to 3.3 V regulators.

• No need for a level shifter
• Operates from 3.3v to 5v max
• Up to 100m range

Pin details:

Key/EN – It is used to bring Bluetooth module in AT commands mode. If Key/EN pin is set to high, then this module will work in command mode. Otherwise by default, it is in data mode. The default baud rate of HC-05 in command mode is 38400bps and 9600 in data mode.

The HC-05 module has two modes,

1. Data mode: Exchange of data between devices.
2. Command mode: It uses AT commands which are used to change the setting of HC-05. To send these commands to module serial (USART) port is used.

VCC – Connect 5 V or 3.3 V to this Pin.

GND – Ground Pin of the module.

TXD – Transmit Serial data (wirelessly received data by Bluetooth module transmitted out serially on TXD pin)

RXD – Receive data serially (received data will be transmitted wirelessly by Bluetooth module).

State – It tells whether the module is connected or not.