Built around the BK3231 Bluetooth chip, this module offers high transmit and receive sensitivity, low power consumption, and stable performance with minimal external components required. Its small form factor and integrated PCB antenna make it suitable for embedded systems, DIY projects, and commercial wireless products.
Features
- Supports Bluetooth v2.1 + EDR with SPP protocol
- UART interface for easy integration with microcontrollers
- Low cost, low power consumption, and compact size
- High sensitivity for stable wireless communication
- Integrated PCB antenna
- Compatible with standard Bluetooth adapters supporting SPP
- Works in Slave mode for secure and controlled connections
Specifications
- Bluetooth Chip: BK3231
- Bluetooth Version: v2.1 + EDR
- Communication Protocol: Serial Port Profile (SPP)
- Operating Frequency: 2.40 – 2.48 GHz
- Operating Range: Up to 10 meters (Power Level 2)
- Host Interface: UART
- Operating Voltage: 2.8 V – 3.6 V
- Power Consumption (Data Transfer): 40 mA
- Sensitivity: -88 dBm (1 Mbps mode)
- Transmit Power: 2 dBm
- Crystal Frequency: 16 MHz
- HID Support: HID v1.0
- Package: 56-pin QFN, 7 mm x 7 mm
Module Configuration
- UART Baud Rate: 9600 bps
- UART Format: 8 data bits, no parity, 1 stop bit (8N1)
- Default Password: 1234
- Operating Mode: Slave only
- Power Supply: 3.3 V
- Note: Level converter is required when interfacing with 5V logic
Pinout Description
- TX, RX: UART communication pins
- RESET: Module reset pin
- P00 – P45: Programmable GPIO pins
- 3.3V: Power supply input
- GND: Ground
- NC: Reserved pins
Pinout Diagram
AT Commands
BK3231 / HC-05 / HC-06 AT Commands
AT commands are used to configure the Bluetooth module. To enter AT mode, power the module while holding the KEY / EN pin HIGH (HC-05) or use the default AT baud rate.
Default AT Mode Settings
- Baud Rate: 38400 (HC-05), 9600 (HC-06 – limited AT)
- Line Ending: Both NL & CR
- Response: OK
Basic AT Commands
| AT Command | Description | Response Example |
|---|---|---|
| AT | Test communication | OK |
| AT+VERSION? | Check firmware version | +VERSION:2.0 |
| AT+NAME? | Get Bluetooth name | +NAME:HC-05 |
| AT+NAME=MyBT | Set Bluetooth name | OK |
| AT+PSWD? | Get pairing password | +PSWD:1234 |
| AT+PSWD=5678 | Set pairing password | OK |
| AT+UART? | Check UART settings | +UART:9600,0,0 |
| AT+UART=9600,0,0 | Set baud rate | OK |
Role & Connection Commands (HC-05)
| AT Command | Description |
|---|---|
| AT+ROLE? | Check role (0=Slave, 1=Master) |
| AT+ROLE=0 | Set Slave mode |
| AT+ROLE=1 | Set Master mode |
| AT+ADDR? | Get module Bluetooth address |
| AT+CMODE=0 | Connect to fixed address only |
| AT+CMODE=1 | Connect to any address |
Notes
- HC-06 supports only a limited AT command set (Slave only).
- AT commands must be sent without pairing.
- Make sure the baud rate matches AT mode, not data mode.
Applications
- Wireless serial communication
- Arduino and microcontroller Bluetooth projects
- Wireless data logging systems
- Industrial and consumer embedded devices
- Bluetooth-based control and monitoring systems
Built around the BK3231 Bluetooth chip, this module offers high transmit and receive sensitivity, low power consumption, and stable performance with minimal external components required. Its small form factor and integrated PCB antenna make it suitable for embedded systems, DIY projects, and commercial wireless products.
Features
- Supports Bluetooth v2.1 + EDR with SPP protocol
- UART interface for easy integration with microcontrollers
- Low cost, low power consumption, and compact size
- High sensitivity for stable wireless communication
- Integrated PCB antenna
- Compatible with standard Bluetooth adapters supporting SPP
- Works in Slave mode for secure and controlled connections
Specifications
- Bluetooth Chip: BK3231
- Bluetooth Version: v2.1 + EDR
- Communication Protocol: Serial Port Profile (SPP)
- Operating Frequency: 2.40 – 2.48 GHz
- Operating Range: Up to 10 meters (Power Level 2)
- Host Interface: UART
- Operating Voltage: 2.8 V – 3.6 V
- Power Consumption (Data Transfer): 40 mA
- Sensitivity: -88 dBm (1 Mbps mode)
- Transmit Power: 2 dBm
- Crystal Frequency: 16 MHz
- HID Support: HID v1.0
- Package: 56-pin QFN, 7 mm x 7 mm
Module Configuration
- UART Baud Rate: 9600 bps
- UART Format: 8 data bits, no parity, 1 stop bit (8N1)
- Default Password: 1234
- Operating Mode: Slave only
- Power Supply: 3.3 V
- Note: Level converter is required when interfacing with 5V logic
Pinout Description
- TX, RX: UART communication pins
- RESET: Module reset pin
- P00 – P45: Programmable GPIO pins
- 3.3V: Power supply input
- GND: Ground
- NC: Reserved pins
Pinout Diagram
AT Commands
BK3231 / HC-05 / HC-06 AT Commands
AT commands are used to configure the Bluetooth module. To enter AT mode, power the module while holding the KEY / EN pin HIGH (HC-05) or use the default AT baud rate.
Default AT Mode Settings
- Baud Rate: 38400 (HC-05), 9600 (HC-06 – limited AT)
- Line Ending: Both NL & CR
- Response: OK
Basic AT Commands
| AT Command | Description | Response Example |
|---|---|---|
| AT | Test communication | OK |
| AT+VERSION? | Check firmware version | +VERSION:2.0 |
| AT+NAME? | Get Bluetooth name | +NAME:HC-05 |
| AT+NAME=MyBT | Set Bluetooth name | OK |
| AT+PSWD? | Get pairing password | +PSWD:1234 |
| AT+PSWD=5678 | Set pairing password | OK |
| AT+UART? | Check UART settings | +UART:9600,0,0 |
| AT+UART=9600,0,0 | Set baud rate | OK |
Role & Connection Commands (HC-05)
| AT Command | Description |
|---|---|
| AT+ROLE? | Check role (0=Slave, 1=Master) |
| AT+ROLE=0 | Set Slave mode |
| AT+ROLE=1 | Set Master mode |
| AT+ADDR? | Get module Bluetooth address |
| AT+CMODE=0 | Connect to fixed address only |
| AT+CMODE=1 | Connect to any address |
Notes
- HC-06 supports only a limited AT command set (Slave only).
- AT commands must be sent without pairing.
- Make sure the baud rate matches AT mode, not data mode.
Applications
- Wireless serial communication
- Arduino and microcontroller Bluetooth projects
- Wireless data logging systems
- Industrial and consumer embedded devices
- Bluetooth-based control and monitoring systems