In this tutorial, we going to discuss how can we interface a microcontroller with the Bluetooth technology. The Bluetooth will work with an Arduino board through the serial communication. The data is received to the Arduino with the HC-05 Bluetooth module through the serial communication and the LED’s will turn ON/OFF according to the receiving data. There are different types of Bluetooth modules are available in the market, but here we are using the HC-05 Bluetooth module because it is commonly used.
What is a Bluetooth Technology?
Generally, we all known that the Bluetooth technology is a wireless technology and it is used to transfer the data between one device to another device. The distance between the transfer of two devices is very less and in this tutorial, the Arduino module is interfaced with the HC-05 Bluetooth module.
HC-05 Bluetooth Module
This Bluetooth module is a serial port protocol (SPP) module and it is used to communicate with the Arduino with the help of serial communication. The HC-05 module is designed for wireless serial communication and this Bluetooth is fully qualified Bluetooth with the version of V2.0+enhanced data rate 3Mbps modulation with a complete 2.4GHz radio transceiver and baseband. For this module, the maximum range of wireless communication is about the 10 meters.
By comparing with the other modules like HC-06 the HC-05 module is better because of the HC-06 module is set as a slave, but the HC-05 module can be used as a master as well as slave. This can enable the communication between the two microcontrollers like two Arduino boards. The general specifications of the HC-05 module are given below.
Specifications of the HC-05 Bluetooth module
- The frequency of this board is 2.4GHz.
- The voltage required for this operation is less which is up to 3-5V.
- The integrated antenna is present.
- UART interface with programmable baud rate.
- Supported baud rates are 9600,19200,38400,57600,115200,230400 and 460800.
- Auto-connect to the last device on power as the default.
Required Components to Interface Arduino with the Bluetooth
The following are the required components to build the interfacing of Arduino with the Bluetooth technology.
- HC-05 Bluetooth module or HC-06 Bluetooth technology
- 220k resistor-3
- 1k & 2k resistor
- Arduino UNO or other Arduino modules
- Connecting wires and LEDs-3
Interfacing Arduino Module with the Bluetooth Technology
The following circuit diagram shows the Arduino Bluetooth module interfacing. The HC-05 Bluetooth module consists of 6 pins from these pins we are using only four pins and other two pins are used for the project as key & state pins. The state command is used to tell that either it is connected or not. The key command forces setup mode if it is brought HIGH before power is applied.
The other four pins are used as a VCC, GND, TXD, and RXD. The VCC pin requires 5V to power up and the RXD pin is communicated with the Arduino with 3.3V. If you connect RXD directly to the Arduino then it will work and the Arduino will be damaged soon. To overcome this voltage divider to convert the 5V into 3.3V with the help of resistor then connect the RX pin through this to the Arduino.
The VCC pin and the ground pin of the HC-05 Bluetooth module to the 5V and the Arduino ground. The Arduino pin 0 is connected to the TX and by the default, it is RX pin. Then to make a voltage divider connect the 1k & a 2k resistor in series, then connect to the RX pin of the HC-05 Bluetooth module to the pin of 1 Arduino through the resistor. The three LED’s are connected to the pins of 8, 9, 10 of the Arduino board.
Arduino Bluetooth Project
Here we are explaining a simple project on home automation, which is based on the Arduino module interfacing with the Bluetooth technology. The components required for the block diagram are Arduino module, Bluetooth device, regulator, rectifier, transmitter, lamp load, Opto-isolator, an Android device and the following image shows the block diagram of Android-based home automation.
The main concept of this project is to develop the home automation system using the Arduino board using the Bluetooth technology and the operation is controlled by the remotely using the Android OS smartphone.
The Bluetooth is interfacing to the Arduino board at the receiver side and on the transmitter side, GUI applications on the phone send the ON/OFF command to the receiver where the load is connected. On the GUI the specific location is touched, then the load can be ON/OFF by operating remotely through this technology. The loads are operated by the Arduino board with the Opto-Isolators and Thyristors using TRIACS.
Application of Arduino interfacing with Bluetooth Technology
- Bluetooth technology can be used in the home appliances
- Smart offices
- Industrial purpose
- Easy and convenient to use
- It is can be operated in remote operation
- It is based on the Android application
In this article, we have explained, how Arduino can be interfaced with the Bluetooth technology. We hope that you have got a better understanding of these projects. Furthermore, any queries regarding this concept, or to implement electronics and electrical projects please give your feedback by commenting in the comment section below. Here is the question for you, What are the function of the Arduino and Bluetooth technology?