HC-06 Bluetooth Module

Overview

HC-06 Bluetooth Serial Communication Module designed for simple wireless UART communication between microcontrollers and smartphones using Bluetooth Classic technology. A compact, low-cost Bluetooth SPP (Serial Port Protocol) module operating primarily in Slave mode for easy wireless serial data transfer.

The HC-06 is widely used in Arduino projects, ESP32 systems, STM32 development, robotics, wireless sensor nodes, smart home systems, and mobile-controlled electronics where simple Bluetooth communication is required.

Compared to the HC-05, the HC-06 is simpler to configure and easier to use for basic Bluetooth applications.

Specifications

Parameter	Value
Model	HC-06
Bluetooth Version	Bluetooth 2.0 + EDR
Frequency	2.4GHz ISM Band
Communication Protocol	SPP (Serial Port Protocol)
Operating Voltage	3.6V – 6V
Logic Level	3.3V TTL
Default Baud Rate	9600bps
Operating Current	~30mA
Communication Range	Up to 10m
Transmission Power	≤4dBm
Interface	UART TTL
Operating Temperature	-20°C to +75°C
Antenna	Onboard PCB Antenna

Pin Configuration

Pin	Description
VCC	Power Supply
GND	Ground
TXD	UART Transmit
RXD	UART Receive

Features

• Bluetooth Serial Communication
• Simple UART interface
• Easy smartphone connectivity
• Low-cost wireless solution
• Compact design
• Compatible with Arduino, STM32, ESP32
• Low power consumption
• Stable wireless communication
• Simple AT command support
• Ideal for beginner projects
• Reliable short-range communication

HC-06 vs HC-05

Feature	HC-06	HC-05
Mode Support	Slave Only	Master + Slave
Configuration	Simple	Advanced
Pins	4 Pins	6 Pins
AT Commands	Limited	Advanced
Complexity	Easy	Medium
Wireless Flexibility	Basic	Advanced
Best For	Smartphone control	Device-to-device communication

Pin Wiring with Arduino UNO

HC-06	Arduino UNO
VCC	5V
GND	GND
TXD	RX (D0)
RXD	TX (D1) via voltage divider

Pin Wiring with ESP32

HC-06	ESP32
VCC	5V
GND	GND
TXD	GPIO16
RXD	GPIO17

Common Applications

• Smartphone-controlled robots
• Bluetooth wireless terminal
• Wireless sensor monitoring
• Home automation
• Arduino wireless projects
• Embedded communication systems
• RC vehicle control
• IoT prototypes
• Wireless debugging

Basic Arduino Example

#include <SoftwareSerial.h>

SoftwareSerial BT(10, 11);

void setup() {
    Serial.begin(9600);
    BT.begin(9600);

    Serial.println("HC-06 Ready");
}

void loop() {

    if (BT.available()) {
        Serial.write(BT.read());
    }

    if (Serial.available()) {
        BT.write(Serial.read());
    }
}

Package Includes

• 1× HC-06 Bluetooth Module

Notes

• HC-06 operates mainly in Slave mode
• Default password is usually 1234
• Default baud rate is 9600bps
• RX pin uses 3.3V logic level
• Suitable for Android Bluetooth SPP communication
• Most HC-06 modules do not support iOS SPP
• Easier to use than HC-05 for simple applications
• Use voltage divider for 5V TX signals

Applications in Embedded Systems

The HC-06 is commonly used in:

• Arduino wireless control
• ESP32 UART communication
• STM32 serial communication
• Robotics projects
• Smart home systems
• Bluetooth sensor systems
• Educational electronics projects

The HC-06 remains a popular beginner-friendly Bluetooth serial module for embedded electronics due to its simplicity, low cost, and reliable UART communication.