HC-05 Bluetooth Serial Module – Master & Slave Mode | UART | Arduino Compatible | Wireless Communication

HC-05 Bluetooth Serial Module – Master/Slave Wireless Module

The HC-05 is a powerful and versatile Bluetooth serial module 
designed for wireless UART communication in Arduino, microcontroller, 
and DIY electronics projects. Unlike basic Bluetooth modules, the HC-05 
supports both Master and Slave modes — giving you full control over 
how devices connect and communicate wirelessly.

📡 KEY SPECIFICATIONS:

- Bluetooth Version: v2.0 + EDR (Enhanced Data Rate)
- Operating Mode: Master & Slave (switchable via AT commands)
- Frequency: 2.4 GHz ISM Band
- Modulation: GFSK
- Max Data Speed: 2.1 Mbps
- Communication Range: Up to 10 meters (open space)
- Operating Voltage: 3.3V – 6V (5V tolerant)
- Operating Current: 30–40 mA
- Default Baud Rate: 9600 bps (Normal) | 38400 bps (AT Mode)
- Default PIN: 1234
- Interface: UART (TX, RX, VCC, GND, EN, STATE)
- Chip: CSR BC417
- AT Commands: 40+ commands supported

✅ KEY FEATURES:

- Supports Master Mode – can initiate connections to other devices
- Supports Slave Mode – accepts connections from phones/PC
- Configurable via AT Commands (name, baud rate, PIN, mode)
- Auto-reconnect to last paired device
- LED status indicator (fast blink = data mode, slow blink = AT mode)
- KEY/EN pin for entering AT configuration mode
- Works with Android & Windows (not iOS)
- Compatible with Arduino, STM32, PIC, Raspberry Pi

📌 PINOUT:
VCC | GND | TXD | RXD | EN (KEY) | STATE

🛠️ APPLICATIONS:
- Arduino to Arduino wireless communication
- Bluetooth robot & car control
- Wireless sensor data logging
- Home automation systems
- Wireless serial monitor
- RC remote control systems
- DIY Bluetooth joystick/gamepad

📦 PACKAGE INCLUDES:
- 1 x HC-05 Bluetooth Serial Module

⚠️ NOTE:
HC-05 RX pin operates at 3.3V logic. Use a voltage divider 
when connecting to a 5V Arduino TX pin to protect the module.
Default pairing PIN: 1234