Bluetooth module HC-05

A simple communication system based on Bluetooth module HC-05. It communicates via the serial UART interface using AT commands.

• status LED connected to the status PIO1 (24) lead indicating a proper connection
• solderedgoldpin connectors to attach module tothe breadboard or connect usingwires.
• EN pins (switches the system to the AT commandsmode) and STATE (connected to the status PIO1 - pin 24 lead).

To start the module, you must connect the supply voltage to a pin marked VCC. The module will be detected by the computer as unknown system or HC-05, to pair both devices, you need to enter the password:1234. In the system will appear a virtual COM port, through which, using any terminal, tha data can be transmitted. The board has leads of the serial interface UART - pins TX and RX that you can connect, for example, to Arduinoor the computer viathe FTDI adapter.

Despite the fact that in the network available are projects, in which the HC-05 system is connected directly to the 5 V pins, for example, Arduino Uno. For security, we recommend the useof a voltage converter 3.3 V - 5 V.

Communication can be tested by pairing the module with the computer and connecting the board using theFTDI converter. In two terminal's windows, you should select appropriate communication ports and also specify the speed of the 9600 bps transmission. If the configuration is correct, the text is sent from one terminal and it will appear on the second.

Configuration of the module is via the popular AT commands, to enter this mode, you need to connect the WAKEUP lead to 3.3 V. Examples of the commands:

• AT- connection testing, in return we get "OK".
• AT+BAUD1- it sets the speed to 9600 bps.

The instructions needs to be sent without the sign of end of the line. More commands can be found in thedocumentation.

Check how to connect the device to a RaspberryPi!

• Voltage: 3.6 V-6 V connected to the VCC pin
• Communication leads are working with voltage 3.3 V (tolerate 5 V)
• Current consumption: approx. 50 mA
• Class 2 - maximum transmitter power + 4 dBm
• Range: up to 10 m
• The password for pairing: 1234
• Standard: Bluetooth 2.0 + EDR
• The SPP profile with possibility to configure via AT commands
• Communication: UART (RX, TX)
• Small dimensions: 37 x 16 mm

• Documentation of the module HC-05
• A set of AT commands
• Example of connection with Raspberry Pi