The HC-05 Bluetooth Module (4-Pin) is a highly reliable and widely used wireless communication module designed for seamless serial data transmission between microcontrollers and Bluetooth-enabled devices such as smartphones, tablets, and PCs.
This module supports both Master and Slave modes, allowing flexible communication setups including device-to-device pairing and wireless control applications.
Equipped with an onboard push button for AT mode configuration, the HC-05 simplifies setup and customization, making it ideal for Arduino, robotics, IoT, and embedded system projects.
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Key Features
• Dual Mode Operation: Supports both Master and Slave modes
• Easy Configuration via AT Commands
• Onboard Button for quick AT Mode activation
• Reliable Bluetooth 2.0 + EDR communication
• Stable serial communication (UART interface)
• Compact 4-pin design (VCC, GND, TXD, RXD)
• LED status indicator for connection and pairing
• Wide compatibility with Arduino, Raspberry Pi, and other MCUs
• Low power consumption suitable for portable applications
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Technical Specifications
• Model: HC-05
• Bluetooth Version: Bluetooth V2.0 + EDR
• Frequency: 2.4 GHz ISM Band
• Modulation: GFSK
• Communication Interface: UART (Serial TTL)
• Default Baud Rate: 9600 bps
• Configurable Baud Rates: Up to 1382400 bps
• Operating Voltage: 3.6V – 6V (typically 5V)
• Logic Level: 3.3V TTL
• Working Current: ~30mA
• Pairing Password: 1234 (default)
• Communication Range: Up to 10 meters (open space)
• Dimensions: Approx. 38 mm × 16 mm
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Applications
• Arduino wireless projects
• Robotics control systems
• Home automation systems
• Wireless data logging
• Bluetooth-controlled cars and drones
• Smart devices and IoT applications
• Industrial monitoring systems
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Competitive Advantages
• One of the most cost-effective Bluetooth modules in the market
• Supports both Master & Slave (unlike HC-06 which is Slave only)
• Easy to configure even for beginners
• Strong community support and documentation
• Reliable and stable connection performance
• Widely used in educational and professional environments