HC-05 Bluetooth Module for Wireless Communication Projects

The HC-05 Bluetooth Module for Wireless Communication Projects enables serial wireless communication between microcontrollers and Bluetooth-enabled devices. It supports both master and slave modes for flexible connectivity in IoT, robotics, and automation projects.

Key Features

• Bluetooth 2.0 + EDR for reliable wireless serial communication
• Master and slave mode configurable via AT commands
• UART TTL interface at 9600 baud (default)
• 3.3V-5V operation with onboard voltage regulator
• Built-in antenna with ~10 meter range
• Easy pairing with smartphones and computers
• AT command support for configuration

Technical Specifications

Applications

• Wireless serial communication with smartphones
• Bluetooth-controlled robots and vehicles
• IoT device configuration via phone app
• Wireless sensor data transmission
• Home automation Bluetooth links
• Wireless debugging and monitoring

Important Notes

• HC-05 uses 3.3V logic on RX pin – use voltage divider from 5V Arduino
• Default pairing password is typically ‘1234’ or ‘0000’
• Enter AT mode by holding KEY pin HIGH during power-on
• Use SoftwareSerial on Arduino to free hardware serial for debugging
• HC-06 is slave-only; HC-05 can be both master and slave