The HC-05 Wireless Bluetooth Module (Bare Module) is a popular and versatile Bluetooth 2.0 device that can be configured to act as both a **Master and a Slave**. Unlike versions with a base plate, this bare module is designed for **SMD (Surface Mount Device) integration** directly onto a custom PCB. It provides a reliable **Serial Port Profile (SPP)** connection, enabling transparent, bi-directional data transmission over a standard UART interface.
✨ Key Features and Benefits
- Supports **Bluetooth 2.0 + EDR (Enhanced Data Rate)**.
- **Dual-mode capability** (Master or Slave) configurable via AT commands.
- Designed for **SMD integration**, allowing for a smaller final product footprint.
- Uses the standard **Serial Port Profile (SPP)** for simple UART data transfer.
- Configuration and setting changes are managed via extensive **AT commands**.
- Operating voltage is typically **3.3V** (logic voltage).
- Pin-out includes key connections like VCC, GND, TXD, RXD, KEY/EN, and STATE/LED.
🔧 Material and Construction Details
| Component | Material / Type | Description |
|---|---|---|
| Bluetooth Chipset | CSR Solution (Typical) | Handles Bluetooth 2.0 communication and SPP |
| Interface | UART (Serial) | Primary communication interface with the host MCU |
| Antenna Type | PCB Trace Antenna | Integrated for wireless communication |
📚 Use Cases and Applications
- Wireless data logging and monitoring systems.
- Remote control for robotic platforms and RC vehicles.
- Custom-designed **embedded electronics** requiring Master/Slave Bluetooth functionality.
- DIY projects with microcontrollers (like **Arduino and Raspberry Pi**) for serial communication.
- Industrial control and monitoring requiring short-range wireless links.
🔍 Technical Specifications
| Specification | Details |
|---|---|
| Model | HC-05 (Bare Module) |
| Bluetooth Standard | Bluetooth 2.0 + EDR |
| Protocol | SPP (Serial Port Profile) |
| Operating Voltage | 2.8V - 3.3V (Logic Level 3.3V) |
| Operating Mode | Master/Slave configurable |
| Range | Typically up to 10 meters (Class 2) |
🧼 Care & Maintenance
This bare module is sensitive to improper soldering heat profiles; follow datasheet recommendations for reflow soldering. Power the module with a stable 3.3V supply. **Do not apply 5V logic** directly to the RXD pin without proper level shifting, as the module operates at 3.3V logic.
⚠ Safety Information
Care must be taken to ensure correct logic level conversion (e.g., using a voltage divider or level shifter) when interfacing the module's RX/TX pins with 5V microcontrollers. Avoid short circuits during mounting. Keep away from excessive moisture and static discharge.
👍👎 Pros & Cons
| Pros | Cons |
|---|---|
| Master/Slave capability for versatile pairing | Requires external 3.3V regulation on the host PCB |
| Small size ideal for embedding and mass production | **Requires logic level shifting** for 5V MCUs (e.g., standard Arduino Uno) |
| Proven, reliable Bluetooth 2.0 SPP performance | Limited to older Bluetooth 2.0 standard (no BLE) |
| Fully configurable via comprehensive AT commands | More difficult to hand-solder and prototype than the base plate version |
🅿 Product Images:
