HC-05 Bluetooth Transceiver Module


This module is commonly used with Arduino, great for starters who wants to build wireless projects!

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SKU: MDU-WRL-BT-HC05 Category: Tags: , , , , ,


This module is commonly used with Arduino, great for starters who wants to build wireless projects!

The?HC-05 is a very cool module which can add two-way (full-duplex) wireless functionality to your projects. You can use this module to communicate between two microcontrollers like Arduino or communicate with any device with Bluetooth functionality like a Phone or Laptop. There are many android applications that are already available which makes this process a lot easier. The module communicates with the help of USART at 9600 or 38400 (default) baud rate hence it is easy to interface with any microcontroller that supports USART. We can also configure the default values of the module by using the command mode.


Operating Voltage 3.6 – 6.0V
Recommended Voltage 5.0V
Operating Current 30mA
Signal Range 10 – 20 meters
Serial Protocol USART
Wireless Protocol Standard IEEE 802.15.1
Mode of Operation Master or Slave
Supported Baud Rate 9600/19200/38400/57600/115200/230400/460800
RX pin voltage 3.3V max.


Only apply for RX pin on the bluetooth module, Arduino boards such as Uno, Nano and Mega board or other microcontrollers output 5V at their I/O pins. You need to use a voltage divider (1K + 2K resistor network) or logic level shifter to step down the 5V signal from microcontroller to 3.3V before feed it into RX pin on bluetooth module. TX pin on the bluetooth module outputs 3.3V signal and Arduino can perceive this voltage as HIGH, so stepping up this signal voltage is not required.

Additional Information

TXD : Transmitter pin, this pin must connect to RX pin of next device

RXD: Receiver pin, this pin must connect to TX pin of next device

There are 6 pins on the HC-05 module, namely EN, VCC, GND, TXD, RXD, STATE. When the HC-05 is paired connection to a device (such as mobile phone), STATE pin will output HIGH, otherwise it will output LOW signal.

The built-in LED on the module indicates the bluetooth connection,

LED Blink Status Meaning
Rapidly Not connected to any device
Slowly Entered AT mode
Twice Connected to target device


  • The module has built-in features such as reverse polarity protection, 3.3V LDO regulator that convert any input voltages range from 3.6 – 6.0V into 3.3V. When it is not paired connection, the current consumption is 30mA, and when it is paired connection, the consumption is 10mA.
  • Do not input voltage higher than 7.0V.
  • Logic voltage level from the HC-05 module is 3.3V, it can be connected to any microcontrollers ranged from 8051, AVR, PIC, ARM, MSP430 and etc. MAX232 is not required for the serial communication.
  • Effective open-space pairing range is 10 meters. Operating more than 10 meters range is possible but connectivity strength is not guaranteed.
  • This module can be set to either MASTER or SLAVE mode, changing device name or password, or acquiring version information via AT commands

Additional information

Weight 5 g