This bare HC-05 module provides Bluetooth 2.0 serial communication without a voltage regulator or breakout board. Ideal for embedded integration into custom PCBs or direct 3.3 V microcontroller interfaces.

Specifications

• Bluetooth Version: 2.0 + EDR (Class 2)
• Frequency: 2.4 GHz ISM band
• Modulation: GFSK
• Operating Voltage: 3.3 V DC (no onboard regulator)
• Logic Level: 3.3 V (direct connection only)
• Default Baud Rate: 9600 (configurable via AT commands)
• Communication Interface: UART (TXD, RXD)
• Roles: Master/Slave (configurable via AT commands)
• Range: ~10 m (open space)
• LED Indicator: Onboard status LED
• Pinout:
  - VCC, GND
  - TXD, RXD
  - EN (key pin for AT mode)
• Dimensions: ~27 mm × 13 mm
• Antenna: Onboard PCB antenna
• Mounting: Solderable header pads
• Packaging: Bare module (no adapter board or voltage regulator)

Features

• Compact and lightweight for embedded PCB integration
• Supports AT command configuration for baud rate, role, and pairing
• Ideal for low-cost wireless serial links
• Compatible with 3.3 V microcontrollers (ESP32, STM32, etc.)
• Common use cases:
  - Bluetooth-enabled embedded systems
  - Wireless sensor nodes and automation
  - DIY remote controls and serial bridges
  - Robotics and wearable electronics