Bluetooth Module HC-05

Bluetooth Module HC-05 – Overview

The Bluetooth Module HC-05 is a compact, reliable class 2 Bluetooth serial transceiver designed for wireless communication between microcontrollers and Bluetooth-enabled devices. Ideal for Arduino, STM32, and other MCU platforms, the HC-05 enables remote control, data logging, and automation without messy wires.

Key Features

• Supports Master and Slave modes for versatile network topologies
• Serial Port Profile (SPP) for transparent UART communication
• Built-in AT command mode for configuring role, baud rate, name, and password
• Bluetooth version 2.0 + EDR for stable two-way data transfer
• Default UART baud rate: 9600 (configurable)
• Operating voltage: 3.3V to 6V with 3.3V TTL interface
• Onboard LED indicators for power and connection status
• Compact size: approx. 27mm x 13mm

Technical Specifications

• Bluetooth version: 2.0 + EDR
• Operating voltage: 3.3V to 6V
• Interface level: 3.3V TTL
• Communication protocol: UART (default 9600 baud)
• Operating modes: Master and Slave
• Communication range: Up to 10 meters (line of sight)
• Onboard LED: Shows status and connection
• Dimensions: Approx. 27mm x 13mm

HC-05 Connections and Pinout

• VCC – 3.3V to 6V supply
• GND – Ground
• TXD – Transmit data (connect to RX of MCU)
• RXD – Receive data (connect to TX of MCU). Note: use a voltage divider or level shifter when connecting to 5V TX pins.
• KEY / EN – Pull high before power-up to enter AT command mode
• STATE – Output showing connection status

Quick Wiring Tips

• Connect HC-05 TXD to MCU RX and HC-05 RXD to MCU TX (use level shifting if MCU is 5V)
• Power from a stable 3.3V to 6V supply; avoid powering from noisy sources
• Pull KEY high and power cycle the module to enter AT command mode

Setting Up and Configuring HC-05

Use AT commands to change the module name, set Master or Slave mode, change the baud rate, and set a PIN. Common steps:

1. Wire VCC and GND, and pull KEY high before powering to enter AT mode.
2. Open a serial terminal at the default AT baud (usually 38400 for AT mode or 9600 for data mode depending on firmware).
3. Send commands like AT, AT+NAME=MyHC05, AT+ROLE=1 (set Master), AT+PSWD=1234 to configure.

Always verify the module responds with OK to confirm settings.

Applications

• Arduino Bluetooth projects and remote control
• Wireless sensor networks and data logging
• Home and industrial automation
• Robot-to-controller communication
• Remote control of electronics and smart lighting

HC-05 vs HC-06 – When to Choose HC-05

HC-05 supports both Master and Slave modes and offers greater configurability through AT commands. If you need two-way communication with flexible roles and advanced setup options, HC-05 is the better choice compared to HC-06.

Why Buy HC-05 from Colgroad?

• Affordable pricing and fast delivery in Islamabad
• 100 percent genuine components tested before shipment
• Technical support and setup tutorials for beginners and professionals
• Suitable for students, engineers, and hobbyists

Order the HC-05 Bluetooth Module Today

Bring wireless connectivity to your microcontroller projects. With the HC-05 Bluetooth module you can control and monitor electronics from your phone, laptop, or other smart devices. Order now to make your project smarter and wireless.

Note: Images are for illustration purposes only.