HC-06 Bluetooth 2.0 Serial Module w/ UART Interface

Connect the HC-06's VCC pin to the Arduino's 3.3V output, GND to GND, TXD to Arduino RX (pin 0), and RXD to Arduino TX (pin 1). Use a voltage divider or logic level converter if your Arduino only outputs 5V logic, as the HC-06's RXD pin is 3.3V tolerant. Ensure you avoid connecting the HC-06's VCC to 5V, as it will damage the module. For initial testing, use the SoftwareSerial library on other digital pins to avoid conflicts with the hardware serial port used for programming.

Yes, you can configure the HC-06 using AT commands sent via its UART interface. Enter AT command mode by connecting the module's KEY pin to VCC before power-on or by sending "AT" once connected. Common commands include AT+NAME to change the visible Bluetooth name, AT+BAUD to set a new baud rate (1 for 1200, 4 for 9600, 8 for 115200, etc.), and AT+PIN to modify the pairing PIN. Remember to update your host device's serial communication speed to match the new baud rate after changing it.

The HC-05 can operate as both a master and slave device, allowing it to initiate connections to other Bluetooth devices. The HC-06 operates only in slave mode, meaning it can only accept incoming connection requests. The HC-05 typically has a command interface for more advanced configuration, while the HC-06 is often simpler and more limited. For most projects where a microcontroller needs to connect to a phone or computer, the slave-only HC-06 is sufficient and often more cost-effective. Pinouts and voltage requirements are generally similar between the two modules.