Baud Rate: 9600 with 8 data bits, no parity and 1 stop bitĬircuit Diagram for Interfacing HC-05 Bluetooth Module with Arduino.The following is a list of few of the default settings of the HC-05 Bluetooth Module. Default Settings of HC-05 Bluetooth Module
In order to select either of the modes, you need to activate the Command Mode and sent appropriate AT Commands.Ĭoming to the Data Mode, in this mode, the module is used for communicating with other Bluetooth device i.e. In Command Mode, you can communicate with the Bluetooth module through AT Commands for configuring various settings and parameters of the Module like get the firmware information, change UART Baud Rate, change module name, set it as either Master or slave etc.Īn important point about HC-05 Module is that it can be configured as Master or Slave in a communication pair. The HC-05 Bluetooth Module can be configured in two modes of operation: Command Mode and Data Mode. Once the module is paired, the LED blinks at a constant delay of 2 seconds. When the module is not paired, the LED blinks or flashes repeatedly. NOTE: The on-board LED is used to indicate the status of the connection. When the module is paired with any device, this pin goes HIGH. This pin goes LOW when the module is not connected to any device. STATE: This is a status indicator pin.TX: It is the Transmitter pin of the UART Communication.As the Module has on-board 3.3V regulator, you can provide +5V supply. +5V: This is the supply pin for connecting +5V.If this pin is connected to GND, the module is disabled. When this pin is floating or connected to 3.3V, the module is enabled. This part of the Module is not discussed in this project.
NOTE: The button present on the board is used to configure the Bluetooth Module in AT Command Mode. Hence, a 3.3V Regulator is used on the board. Image below shows the pins and other components on a typical HC-05 Bluetooth Module.Īn important point to remember is the HC-05 Bluetooth Module works on a logic level of 3.3V. In my case, the board uses the UART communication.Ĭoming to the pins of the Bluetooth Module, generally, four pins are sufficient for successfully enabling a wireless communication link but the modules produced now-a-days come with six pins namely: VCC, GND, TX, RX, EN and STATE. The HC-05 Module supports for UART, USB as well as SPI communication and depending on the application, necessary pins can be used. The following image shows one such HC-05 Bluetooth Sub Module (the green board mounted on the blue board) being used as a part of a complete Bluetooth Module. Such Modules come as surface mount board and several third-party manufacturers use these board to build a more complete system with necessary pins and components. Generally, the HC-05 Bluetooth Module, or the HC-05 Sub Module, to be precise, comes with the BC417 IC along with a flash memory. This module is based on BC417 Single Chip Bluetooth IC that is compliant with Bluetooth v2.0 standard and with support for both UART and USB interfaces.
HC-05 Bluetooth Module is a simple Wireless Communication device based on the Bluetooth Protocol. If you take a look around the electronics DIY and hobbyists community, HC-05 Bluetooth Module is the device of choice for implementing Bluetooth Communication based projects. So, in this project/tutorial, I will talk a little bit about the HC-05 Module. I have implemented several projects using HC-05 Bluetooth Module like Robotic Arm, Home Automation, LED Matrix etc.īut in all those projects, I have not discussed a lot about the Bluetooth Module, except for what is required to get the project done. It is one of the most popular and most frequently used low range communication for data transfer, audio systems, handsfree, computer peripherals etc.Ĭoming to usage of Bluetooth Communication in DIY projects, HC-05 Bluetooth Module is the go to device.