HC-06 Bluetooth Module for Arduino

HC-06 Bluetooth serial pass-through module wireless serial communication
HC-06 is a Bluetooth module designed for establishing short range wireless data communication between two microcontrollers or systems. The module works on Bluetooth 2.0 communication protocol and it can only act as a slave device. This is cheapest method for wireless data transmission and more flexible compared to other methods and it even can transmit files at speed up to 2.1Mb/s.
HC-06 uses frequency hopping spread spectrum technique (FHSS) to avoid interference with other devices and to have full duplex transmission. The device works on the frequency range from 2.402 GHz to 2.48GHz.
Pin Description:

Pin
Name
Function

1
Key
The pin state determines whether the module works in AT command mode or normal mode
[High=AT commands receiving mode(Commands
response mode), Low or NC= Bluetooth module normally working]

2
Vcc
+5V Positive supply needs to be given to this pin for powering the module

3
Gnd
Connect to ground

4
TXD
Serial data is transmitted by module through this pin (at 9600bps by default), 3.3V logic

5
RXD
Serial data is received by module through this pin (at 9600bps by default),3.3V logic

6
State
The pin is connected to the LED on the board to represent the state of the module