HC-05 Bluetooth Module and Arduino Beginner Tutorial


What is the HC-05 Bluetooth Module?

The HC-05 module enables wireless communication between electronic devices over short distances. It uses Bluetooth technology to establish a serial communication link between a microcontroller or other embedded systems and a host device like a smartphone, tablet, or computer.

What is the HC-05 used for?

HC-05 modules are widely available and relatively easy to integrate into electronics projects. However, it's essential to consult the module's datasheet and documentation for detailed specifications and usage instructions, especially regarding power requirements, communication protocols, and configuration options. Additionally, be aware of any limitations or compatibility issues when using the HC-05 module with specific microcontrollers or host devices.

Key Features:

1. Bluetooth Version: HC-05 is typically based on Bluetooth version 2.0 + EDR (Enhanced Data Rate).

2. Serial Communication: It communicates with the host microcontroller using serial UART (Universal Asynchronous Receiver-Transmitter) communication protocol.

3. Operating Voltage: Most HC-05 modules operate at 3.3V or 5V, making them compatible with a wide range of microcontrollers and development boards.

4. Operating Range: The effective range of communication varies depending on the conditions but is typically around 10 meters (class 2).

5. Configuration Modes: The HC-05 module can operate in different modes, including AT command mode for configuration and transparent communication mode for data transfer.

6. PIN Interface: It has a set of pins for power supply, ground, serial communication (TX and RX), and mode selection (e.g., AT mode).

7. Pairing: It supports both master and slave modes, allowing it to connect to other Bluetooth devices as either the primary (master) or secondary (slave) device.

How does HC-05 control LED?

Note: The HC-05 Module isn't compatible with iOS.

To control an LED using an Arduino Uno R3 and an HC-05 Bluetooth module, you'll need to follow these general steps:

1. Hardware Setup:
Connect the HC-05 module to the Arduino Uno R3. Typically, you'll connect the HC-05 module's TX pin to Arduino's RX pin, and the HC-05's RX pin to Arduino's TX pin. Also, ensure that the HC-05 module is powered properly (3.3V or 5V depending on the module).
Connect an LED and a current-limiting resistor to one of the digital output pins of the Arduino Uno R3. For example, connect the anode of the LED to a digital pin (e.g., pin 13) and connect the cathode through a resistor (220-330 ohms) to ground.

2. Software Setup:
Write a sketch (Arduino program) that listens for commands over the serial port and controls the LED accordingly.
Pair your HC-05 module with your Bluetooth-enabled device (e.g., smartphone or computer).

3. Bluetooth Communication:
Use a serial terminal app on your Bluetooth-enabled device to send commands (e.g., '1' to turn on the LED, '0' to turn it off) to the HC-05 module connected to the Arduino Uno R3.

4. Testing:
Upload the sketch to your Arduino Uno R3. Power up the Arduino Uno R3 and ensure that the HC-05 module is paired with your Bluetooth device.
Open the serial terminal app on your Bluetooth device and send commands to control the LED.

Components and Supplies

Total price:$56.00 $36.00


# Pin Function
1 State It can be used as a feedback to check if Bluetooth is working properly.
2 RXD Receive Serial Data. Every serial data given to this pin will be broadcasted via Bluetooth.
3 TXD Transmits Serial Data. Everything received via Bluetooth will be given out by this pin as serial data.
4 Ground Ground pin of module
connect to system ground.
5 Vcc Powers the module. Connect to +5V Supply voltage
6 EN This pin is used to toggle between Data Mode (set low) and AT command mode (set high). By default it is in Data mode
Lonely Binary Project Pinout


# HC-05 Pin UNO R3 Pin
1 VCC 5V
Lonely Binary Project Wiring


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