How to Use hc06: Examples, Pinouts, and Specs

The HC-06 is a Bluetooth module designed for wireless communication, commonly used in embedded systems and IoT projects. It operates as a slave device, allowing microcontrollers to connect and communicate with smartphones or other Bluetooth-enabled devices. The module is simple to use, cost-effective, and widely supported, making it a popular choice for hobbyists and professionals alike.

• Wireless data transmission between microcontrollers and smartphones
• Home automation systems
• Remote control of devices
• IoT (Internet of Things) projects
• Robotics and wireless sensor networks

The HC-06 Bluetooth module has the following key technical specifications:

The HC-06 module has 4 pins, as described in the table below:

1. Power the Module: Connect the VCC pin to a 5V power source and the GND pin to ground.
2. Connect to a Microcontroller:
   • Connect the TXD pin of the HC-06 to the RX pin of the microcontroller.
   • Connect the RXD pin of the HC-06 to the TX pin of the microcontroller. Use a voltage divider if the microcontroller operates at 5V logic levels to avoid damaging the HC-06 (which uses 3.3V logic).
3. Pair the Module:
   • Power on the HC-06. The onboard LED will blink rapidly, indicating it is in pairing mode.
   • Search for Bluetooth devices on your smartphone or computer. The HC-06 will appear as "HC-06."
   • Pair with the module using the default PIN code, which is usually 1234 or 0000.
4. Send and Receive Data:
   • Use a serial communication program (e.g., Arduino Serial Monitor) to send and receive data wirelessly.

• Voltage Levels: Ensure the RXD pin does not receive more than 3.3V. Use a voltage divider or level shifter if necessary.
• Baud Rate: The default baud rate is 9600 bps. Ensure your microcontroller's UART settings match this value.
• Range: The module works best within 10 meters in an unobstructed environment. Walls and other obstacles may reduce the range.
• Avoid Interference: Keep the module away from sources of electromagnetic interference (e.g., motors, high-frequency circuits).

Below is an example of how to use the HC-06 with an Arduino UNO to send and receive data:

#include <SoftwareSerial.h>

// Create a SoftwareSerial object to communicate with the HC-06
SoftwareSerial BTSerial(10, 11); // RX, TX pins for HC-06

void setup() {
  Serial.begin(9600); // Start the hardware serial communication
  BTSerial.begin(9600); // Start the software serial communication with HC-06

  Serial.println("HC-06 Bluetooth Module Test");
  Serial.println("Send data from your Bluetooth device to see it here.");
}

void loop() {
  // Check if data is available from the HC-06
  if (BTSerial.available()) {
    char c = BTSerial.read(); // Read a character from HC-06
    Serial.print("Received: ");
    Serial.println(c); // Print the received character to Serial Monitor
  }

  // Check if data is available from the Serial Monitor
  if (Serial.available()) {
    char c = Serial.read(); // Read a character from Serial Monitor
    BTSerial.write(c); // Send the character to HC-06
  }
}

• Connect the HC-06's TXD pin to Arduino pin 10 and RXD pin to Arduino pin 11.
• Open the Serial Monitor and set the baud rate to 9600 to test communication.
• Use a Bluetooth terminal app on your smartphone to send and receive data.

1. The HC-06 is not visible during pairing:

   • Ensure the module is powered on and the LED is blinking rapidly.
   • Check the wiring, especially the VCC and GND connections.
   • Verify that the Bluetooth device you are using supports Bluetooth 2.0.

2. Data is not being transmitted or received:

   • Ensure the baud rate of the microcontroller matches the HC-06's default baud rate (9600 bps).
   • Check the TX and RX connections. Ensure they are not swapped.
   • If using a 5V microcontroller, ensure the RXD pin of the HC-06 is protected with a voltage divider.

3. The module disconnects frequently:

   • Ensure the module is within the specified range (10 meters).
   • Minimize interference from other wireless devices or physical obstructions.

4. The default PIN code does not work:

   • Try common default PINs such as 1234 or 0000.
   • If the PIN has been changed, reset the module to factory settings (refer to the manufacturer's documentation).

Q: Can the HC-06 act as a master device?
A: No, the HC-06 is designed to operate only as a slave device. For master functionality, consider using the HC-05 module.

Q: Can I change the baud rate of the HC-06?
A: Yes, the baud rate can be changed using AT commands. Refer to the manufacturer's documentation for details.

Q: Is the HC-06 compatible with Arduino?
A: Yes, the HC-06 is fully compatible with Arduino and other microcontrollers that support UART communication.

Q: How do I reset the HC-06 to factory settings?
A: Use AT commands to reset the module. For example, send the AT+ORGL command via a serial terminal.

By following this documentation, you should be able to successfully integrate and use the HC-06 Bluetooth module in your projects.