HC-06 vs. HC-05 Bluetooth Module: What is the difference between HC-06 and HC-05?

The HC-06 Bluetooth module is intended for use with two microcontrollers or systems to establish short-range wireless data communication. Its operation becomes transparent to the user after it is associated with a master Bluetooth device, such as a PC or smartphone. All data received through the serial input is sent over the air right away.

HC-06

The HC-05 is a Bluetooth Serial Port Protocol module, which means it communicates with the Arduino using serial communication. This module features a BC417 Single-Chip Bluetooth IC that supports both the UART and USB interfaces and is compliant with the Bluetooth v2.0 standard.

HC-05

HC-06 and HC-05 Pin and Entering AT Mode

For HC-05:

Connect the Rx pin of the Bluetooth module to the Tx pin of the USB  to TTL converter, and the Tx pin of the Bluetooth module to the Rx pin of the converter for the HC-05. Connect their ground as well, but leave the Vcc disconnected for now. You'll need to short the key pin with the Vcc first. On a breadboard, or in any other way, connect key pin and Vcc,  Connect the Vcc of the bt module to the Vcc of the USB  to the TTL converter after all other pins are connected. The led on the module will now blink at a 2-second interval.

That means it has entered the AT mode. If the led blinks faster then AT mode was not entered. Disconnect Vcc.  check your circuit, and try again. If it does not work then there's a chance that your KEY pin of the module is not really soldered to the KEY  of the main chip, i.e. the 34th pin,  You can check that with the help of a multimeter.

For HC-06:

Simply connect the module's Rx to the USB-TTL converter's Tx and the module's Tx. Ground and Vcc should be connected. The module is in AT mode. Didn't see that one coming, right? :P Turns out the HC-06  module is permanently configured to be a slave and it is always in AT mode when not paired to any other device. As a result, unlike the HC-05, there is no confirmation led blinking to indicate that it is in AT mode,  To change the default settings, simply turn on the module and provide the AT commands.

The push-button switch    is used to bring the EGBT-045MS / HC-05  in to AT mode by connecting VCC  (3.3v) to pin 34. There are two AT modes  , which I call "small mode" and "full mode." When you push the button switch    for a few seconds, the modules  go into the tiny model, which means that not all commands  operate. When the switch  is closed, the modules  enter full AT mode, which allows them to respond to all AT commands  . When the switch  is released, pin 34 is set to LOW.

Because most HC-06   modules  lack a button switch    (the space is empty), raising pin 34 HIGH on the HC-06  has no effect  .

The Bluetooth module is used for wireless communication between two microcontrollers.

It is used in Home Automation systems

Hc-05 is a Bluetooth serial port module with master-slave integration. The master-slave can be switched with rich and complete instructions.

Hc-06 is a Bluetooth serial port module with master-slave integration. The master-slave can be switched by command, and the command is less than the-05, so it is easy to use.