HC-05 Bluetooth Module On Board

The HC-05 is a full-duplex Bluetooth 2.0 Serial Port Protocol (SPP) module that adds wireless serial communication to any microcontroller project. Unlike the HC-06, the HC-05 can operate as both master and slave — making it capable of initiating connections as well as receiving them. Pair it with any Arduino, ESP32, or STM32 board for instant cable-free serial communication.

🔹 Key Applications

• Wireless data link between Arduino and Android/PC applications
• Bluetooth remote control of robots and RC vehicles
• Wireless sensor data logging to mobile devices
• Cable-free UART debugging and firmware flashing
• Bluetooth-connected IoT sensor nodes
• Master-slave Bluetooth bridge between two microcontrollers

🔹 Why Choose This Module?

• Master AND slave modes — can initiate or receive connections
• Full-duplex UART — simultaneous send and receive
• AT command configurable — baud rate, name, PIN all adjustable
• 3.3 V logic with 5 V tolerant power input — Arduino-ready
• Up to 10 m range — reliable in typical workshop environments

🔹 Technical Specifications

• Bluetooth Version: 2.0 + EDR
• Mode: Master / Slave (configurable via AT commands)
• Interface: UART (TX/RX)
• Operating Voltage: 3.3 V – 5 V
• Logic Level: 3.3 V (use voltage divider on RX from 5 V MCU)
• Range: Up to 10 m
• Baud Rate: Default 9600 (configurable 1200–1382400)

🔹 What's Included

1 × HC-05 Bluetooth Module

🔹 Pro Tip

💡 Use a voltage divider (1 kΩ + 2 kΩ) on the RX pin when interfacing with a 5 V Arduino — the HC-05's logic is 3.3 V. Enter AT command mode by holding the button while powering on, then send AT commands at 38400 baud to configure name, PIN, and baud rate.

⚠️ Note: Always ensure proper heat dissipation and correct voltage configuration before powering connected devices.