HC-05 BLUETOOTH
Bluetooth is considered as the important wireless communication technic used in systems to transfer information between devices and HC-05 is an easy-to-use Bluetooth serial port protocol module.
HC-05 is a version2.0 Bluetooth module includes in the HC series Bluetooth module, it is easy to interface device which is been known as the prototype system, which are been mainly used at hobbyist projects and also at devices not having Bluetooth communication.
HC-05 Bluetooth module Specification & features
- HC-05 is 0 enhanced data rate Bluetooth module
- The maximum range of communication: <100m
- Frequency range: 4GHz
- Modulation: GFSK (Gaussian frequency-shift keying)
- Supply voltage: +3.3v to 6.0v
- Supply current: 30mA
- Sensitivity: -80dBM at 0.1% BER
- Emission power: ≤ 4dBm, class2
- Speed: 3mbps at asynchronous communication & 1mbps at synchronous
- Supported baud rate: 9600,19200,38400,57600,115200,230400,460800
- Working temperature: -20 to +75°C
- HC-05 Bluetooth follows the IEEE 802.15.1 standardized protocol
- Serial communication is done with UART and TTL compatible protocol
- Auto-connection function with last devices on power
- Uses CSR Blue core 04-external single-chip Bluetooth system with CMOS technology.
- Uses AFH (adaptive frequency hopping) feature
- It has the ability to works as master/slave mode on a system.
- Total size of the module: 26.9mm x 13mm x 2.2 mm
PINOUT DETAILS OF HC-05 BLUETOOTH MODULE
It is the PINOUT details of the whole HC-05 Bluetooth module
| Pin no: | Pin name: | Description |
| Pin01 | Enable pin | It is used to set data values at a high and low level |
| Pin02 | VCC+ | It is the positive supply provided (+5v) |
| Pin03 | GND | Ground |
| Pin04 | TX | Transmitter serial port |
| Pin05 | RX | Receiver serial port |
| Pin06 | State | It is used to indicate the module at ON/OFF state |
HC-05 BLUETOOTH MODULE PARTS
In this category, we try to explain some of the important parts of the HC-05 Bluetooth module.
BC417 Bluetooth IC
It is a Bluetooth IC commonly used at Arduino compatible, they had 3.3v operating voltage and had a waveband range of 2.4GHz to 2.8GHz.
26MHz crystal oscillator
It is the most common crystal oscillator frequency range used at mobile phones and electronic circuits.
Flash memory IC
These types of flash memory IC had applications on mobile phones, digital cameras, etc…
Antenna trace on PCB
It is an onboard antenna trace on PCB, the antenna is embedded with a PCB board.
These types of antenna traces could handle a wide range of bandwidth, the thin film-like structure makes the antenna more compactable and weightless.
HC-05 BLUETOOTH DATASHEET
If you need the datasheet in pdf please click this link
HC-05 BLUETOOTH MODE OF OPERATION
The normal operation of an HC-05 Bluetooth module at system is to introduce a wireless communication two between devices, to transfer information, communicate with each other, and also to communicate with the board.
Bluetooth is a safer and efficient way to communicate between two systems, this is why applications based on Bluetooth are always there at almost all systems.
The natural operation of the HC-05 Bluetooth module is divided into two different modes,
- Data mode: Establish communication between two systems to communicate with each other and exchange data with each other.
- Command mode: on this mode, we actually can make changes to the HC-05 Bluetooth module.
Data mode
source: electronicwings
The figure will help you to understand the interfacing of the HC-05 Bluetooth module with a PC system and then establish a pathway to communicate with a smartphone.
This is just an example network circuit, for to make a Bluetooth wireless communication, you can use multiple systems to make communication between each other.
Command mode
This is how we need to make the connection between HC-05 Bluetooth and microcontrollers before getting into a command mode.
The command mode is used to made changes at the HC-05 Bluetooth module board, the change is like the change of passcode, baud rate, and name of the Bluetooth, etc.
The command mode is made by connecting the HC-05 Bluetooth module with serial to USB converter and PC.
The AT command is commonly used for making changes at the HC-05 module using the PC.
Uses of HC-05 Bluetooth module
- We already know the HC-05 Bluetooth module is a prototypical board, so a project based on the Arduino board is the main application of the HC-05 module.
- Using the HC-05 module, communication will happen between laptops, computers, and mobile phones.
- Used to create communication between microcontrollers
- Wireless robots and home automation
Projects based on HC-05 Bluetooth module
The projects based on the HC-05 Bluetooth module are always like Hobbyists projects, this is because the HC-05 module is a prototypical Bluetooth board.
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Arduino based model home automation project via HC-05 Bluetooth module
source: electronicwings
The shows the home automation connection diagram, the project consists of three major components relay board, Arduino-UNO board, and HC-05 Bluetooth module.
The circuit working operation is much simple, at first, we need to establish a connection between the Bluetooth module and a device, for example, a smartphone and then we can control the bulb or any home appliance using a smartphone.
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Android controlled robot car using HC-05 Bluetooth module
source: hobbyprojects
The figure shows the android controlled robot car project consists of an 89c2051 microcontroller, L293D motor controlling board, and HC-05 Bluetooth module.
The operation of this project is purely based on Bluetooth, we can use android devices to control the movement of the robot.
