HC-05 BT 6pin Bluetooth Module with Button (Original version Type-B)

SKU: FA2039-0
Bluetooth Protocol

Bluetooth V2.0 + EDR
Operating Voltage

3.6V – 6.0V DC
Logic Level (I/O)

3.3V (5V tolerant with current limiting)
Operating Current

30mA (Pairing); 8mA (Connected/Communication)
Frequency Band

2.4GHz ISM Band
Modulation

GFSK (Gaussian Frequency Shift Keying)
Default Baud Rate

9600 (Data Mode) / 38400 (AT Command Mode)
Default Pairing PIN

1234 or 0000
Transmission Range

Up to 10 Meters (Open space, Class 2)
Sensitivity

≤ -84dBm at 0.1% BER
Product Description
The HC-05 (Type-B) is a versatile and widely-used Bluetooth 2.0+EDR (Enhanced Data Rate) module designed for transparent wireless serial communication. Unlike the HC-06 module, which can only act as a “Slave,” the HC-05 is a Master/Slave dual-role module. This means it can either wait for a connection from a phone/PC or proactively initiate a connection to another Bluetooth device (such as another HC-05).
The “Type-B” version features a dedicated onboard button for easier access to AT Command Mode. By holding the button during power-up, users can easily configure settings such as device name, pairing PIN, baud rate, and operational role (Master/Slave). Mounted on a 6-pin breakout board, it includes a built-in voltage regulator and level shifting, making it 5V-tolerant and ideal for seamless integration with Arduino, Raspberry Pi, and industrial PLC systems.
Key Features
  • Master/Slave Switching: Fully configurable via AT commands to act as either a central controller (Master) or a peripheral device (Slave).
  • Onboard Configuration Button: Simplifies the process of entering “Command Mode” for setup without needing complex jumper wiring.
  • Transparent Transmission: Acts as a wireless serial cable; once paired, data sent to the RX pin appears at the connected device’s TX pin.
  • CSR BlueCore4 Technology: High-performance, low-power 2.4GHz radio frequency with external 8Mbit Flash memory.
  • Wide Voltage Compatibility: The integrated baseboard supports a 3.6V to 6V power input.
  • Status LED Indicator: Built-in LED provides visual feedback for pairing status (fast flash), AT mode (slow flash), and connected status (double flash).
Usage Scenarios
  • Single Users & Hobbyists: Wireless remote-controlled robots, DIY home automation via smartphone apps, and wireless data logging from sensors to a PC.
  • Business & Industrial: Wireless serial debugging for CNC machines, wireless communication between two PLCs, cable replacement in factory floor environments, and handheld diagnostic tools.
Q: What is the difference between the HC-05 and the HC-06?

The HC-05 can be configured as both a Master and a Slave, meaning it can connect to other modules. The HC-06 is Slave-only, meaning it can only wait for a master (like a phone) to connect to it.

Q: How do I enter AT Command Mode on the Type-B module?

Disconnect the power, hold down the onboard button, and then reconnect the power. The LED should begin to flash slowly (once every 2 seconds), indicating it is ready to receive configuration commands at 38400 baud.

Q: Can I use this with an iPhone (iOS)?

No. The HC-05 uses Bluetooth Classic (2.0), which iOS does not support for serial data transfer. For Apple devices, you should use a BLE (Bluetooth Low Energy) module like the HM-10 or CC2541. It works perfectly with Android, Windows, and Linux

Q: Why can't my 5V Arduino talk to the module?

While the power pin (VCC) accepts 5V, the RXD pin of the module is 3.3V logic. For long-term reliability, we recommend using a simple voltage divider (two resistors) between the Arduino TX and the HC-05 RXD.

Q: Can I change the name of the Bluetooth device?

Yes. In AT Command Mode, use the command AT+NAME=YourName to customize how the device appears during a scan.

Q: Can I connect two HC-05 modules together?

Yes. You must set one module to Master (AT+ROLE=1) and the other to Slave (AT+ROLE=0). Once configured with the same pairing code, they will automatically find and connect to each other

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