What is the HC-06 Bluetooth Module?

The HC-06 Bluetooth module is a small, low-cost, and easy-to-use wireless communication device that operates on the Bluetooth 2.0 protocol. It is designed to establish a serial communication link between a microcontroller and other Bluetooth-enabled devices, such as smartphones, tablets, or computers. The module supports a range of up to 10 meters and can be easily integrated into various projects requiring wireless data transfer.

HC-06 Bluetooth Module Pinout

The HC-06 Bluetooth module has a simple pinout consisting of four pins:

Pin	Name	Description
1	VCC	Power supply (3.3V to 6V)
2	GND	Ground
3	TXD	Transmit data (connected to the microcontroller’s RX pin)
4	RXD	Receive data (connected to the microcontroller’s TX pin)

It is important to note that the HC-06 module operates at 3.3V logic levels. If you are using a 5V microcontroller, such as an Arduino Uno, you may need to use a logic level converter to ensure proper communication and avoid damaging the module.

Key Features of the HC-06 Bluetooth Module

The HC-06 Bluetooth module offers several features that make it an attractive choice for wireless communication projects:

1. Bluetooth 2.0 compliance: The module supports the Bluetooth 2.0 protocol, which provides a reliable and secure connection.
2. Easy to use: The HC-06 module is designed to be user-friendly and can be easily integrated into projects with minimal setup.
3. Low power consumption: With a low power consumption of around 30mA to 40mA, the HC-06 module is suitable for battery-powered applications.
4. Configurable baud rate: The module supports a wide range of baud rates, from 1200bps to 1382400bps, which can be configured using AT commands.
5. Small form factor: The compact size of the HC-06 module (27mm x 13mm x 2mm) makes it ideal for space-constrained projects.

Applications of the HC-06 Bluetooth Module

The HC-06 Bluetooth module finds applications in various fields, including:

1. Home automation: The module can be used to control smart home devices, such as lights, thermostats, or security systems, using a smartphone or tablet.
2. Robotics: HC-06 modules enable wireless communication between robots and control devices, allowing for remote control and monitoring.
3. Industrial automation: In industrial settings, the HC-06 module can be used for wireless data acquisition, remote monitoring, and control of machinery.
4. Medical devices: The module can be integrated into medical devices for wireless data transmission, such as in wearable health monitors or telemedicine applications.
5. IoT projects: The HC-06 module is a popular choice for Internet of Things (IoT) projects, enabling wireless communication between sensors, actuators, and cloud platforms.

Working Principle of the HC-06 Bluetooth Module

The HC-06 Bluetooth module operates as a slave device, meaning it can only accept incoming connections from a master device, such as a smartphone or computer. The module communicates with the microcontroller using the Universal Asynchronous Receiver/Transmitter (UART) protocol, which allows for serial data transmission.

Establishing a Connection

To establish a connection between the HC-06 module and a master device, follow these steps:

1. Power on the HC-06 module and the master device.
2. On the master device, search for available Bluetooth devices. The HC-06 module will appear as “HC-06” or a custom name if configured.
3. Pair the master device with the HC-06 module. The default pairing code is “1234” or “0000”.
4. Once paired, the master device can establish a serial connection with the HC-06 module using a terminal application or custom software.

Configuring the HC-06 Module

The HC-06 module can be configured using AT commands sent through the serial connection. Some common AT commands include:

Command	Description
AT	Test the connection
AT+NAMExxx	Set the module’s name to “xxx”
AT+BAUDx	Set the baud rate (x = 1-9, see datasheet for values)
AT+PINxxxx	Set the pairing code to “xxxx”

To enter AT command mode, power on the module while holding the “KEY” pin high. Once in AT command mode, you can send the desired commands to configure the module. Remember to reset the module after making changes for them to take effect.

Data Transmission

Once a connection is established and the module is configured, data can be transmitted between the microcontroller and the master device. The microcontroller sends data to the HC-06 module through its TX pin, which is connected to the module’s RX pin. The HC-06 module then transmits the data wirelessly to the master device. Similarly, data sent from the master device is received by the HC-06 module’s TX pin and forwarded to the microcontroller’s RX pin.

Example Arduino Code for HC-06 Bluetooth Module

Here’s a simple Arduino code example that demonstrates how to use the HC-06 Bluetooth module to send and receive data:

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(2, 3); // RX, TX

void setup() {
  Serial.begin(9600);
  BTSerial.begin(9600);
}

void loop() {
  if (BTSerial.available()) {
    char data = BTSerial.read();
    Serial.write(data);
  }

  if (Serial.available()) {
    char data = Serial.read();
    BTSerial.write(data);
  }
}

In this example, a software serial connection is established using pins 2 (RX) and 3 (TX) on the Arduino. The loop() function continuously checks for incoming data from both the HC-06 module and the Arduino’s serial monitor. When data is received, it is forwarded to the other end, allowing for bidirectional communication.

Frequently Asked Questions (FAQ)

1. What is the range of the HC-06 Bluetooth module?
   The HC-06 Bluetooth module has a typical range of 10 meters (33 feet) in open space. However, the actual range may vary depending on factors such as obstacles, interference, and antenna design.

2. Can I connect multiple HC-06 modules to a single master device?
   Yes, you can connect multiple HC-06 modules to a single master device, but you will need to establish separate serial connections for each module. Keep in mind that the maximum number of connections may be limited by the master device’s capabilities.

3. Is the HC-06 module compatible with iOS devices?
   Yes, the HC-06 module is compatible with iOS devices, as long as the iOS device supports Bluetooth 2.0 or higher and has a suitable app for establishing a serial connection.

4. Can I use the HC-06 module for audio transmission?
   No, the HC-06 module is designed for serial data transmission only. It does not support audio transmission. For wireless audio applications, you may consider using other modules, such as the BC127 or RN52.

5. How do I update the firmware on the HC-06 module?
   The HC-06 module does not support firmware updates. If you require a module with firmware update capabilities, consider using the HC-05 or other more advanced Bluetooth modules.

Conclusion

The HC-06 Bluetooth module is a versatile and user-friendly device that enables wireless serial communication between microcontrollers and other Bluetooth-enabled devices. With its simple pinout, configurable features, and low power consumption, the HC-06 module is well-suited for a wide range of applications, from home automation to industrial monitoring. By understanding the module’s working principle and following the guidelines provided in this article, you can easily integrate the HC-06 module into your projects and unleash the potential of wireless communication.