The advancement of technology is growing day to day; many changes have taken place till date and can witness in the improvement of technology. Most of the equipment’s can be operated with the help of Bluetooth technology. Where life became so easy in the present world when compared to previously. Bluetooth technology is a user friendly where, it can be operated by any individual. It is a high speed and low powered technology. It is a wireless technology, which is specially designed to connect with different devices such as phones, tabs, Laptops, and many other portable equipment together.
It is used for It is a used for short distances without requiring any wire typically up to 30 feet. Low-cost transceivers are embedded into the devices where the frequency band will be 2.45GHz and supports till 721KBps along with three voice channels. On international agreement the frequency band has been set for the use of medical devices (ISM), rd-compatible with 1.0 devices, industrial and scientific. Bluetooth can be either connected multipoint and point to point. It can connect almost up to eight devices.
Working Principle of Bluetooth Technology
The working principle of Bluetooth is very simple which can be understood very fast. Generally Bluetooth Network consists of a Personal Area Network (PAN) or Piconet which contains a maximum of 8 Bluetooth peer devices and a minimum of 2. A master initiates the communication with other devices and guides the trafﬁc and communications link between itself and the slave devices associated with it.
A slave will only respond to the master device. Slave devices have to synchronize their transmit/receive timing with the masters. The master device sends a radio signal and waits for the response from the particular slave devices within the range of the given addresses. The clock with the master device, once the slaves respond and synchronize with their frequency.
The list of Bluetooth versions mainly includes Bluetoothv1.0 and v1.0B, Bluetoothv1.1, Bluetoothv1.2, Bluetoothv2.0+EDR, Bluetoothv2.1+EDR, Bluetoothv3.0+HS, Bluetoothv4.0, Bluetoothv4.1, Bluetoothv4.2, Bluetooth v5
Applications of Bluetooth
- PC Cordless
- Portable computers
Android Mobile Technology
An Android is a Linux based operating system, which is used in touch screen gadgets like smart phones, tablets, etc. Android Operating Systems were established and owned by Google. The different versions released are Cupcake, Donut, Éclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwich, Jelly Bean, KitKat & Lollipop.
This OS uses both virtual keyboard and touch inputs to operate on-screen objects. It was designed for touch screen equipment and game equipment like personal computers, electronic devices and cameras. Android is the highest selling OS. This is an open source; anyone can install and use it to build their own applications.
The Linux kernel will be used for Android OS and it supports an extensive range of hardware drivers. It controls the input and output requests from the software. It is also called as the heart of the Android. This offers basic functionalities of a system like memory and process management, device managements such as camera, display, keypad, etc. The Linux itself does not connect directly with the user, but rather networks with the shell & latest programs and also with the hardware devices on the system.
The runtime of an Android OS provides a key component, namely DVM (Dalvik Virtual Machine) which is a type of the Java virtual machine. The processing virtual machine in Android OS is Dalvik VM. This software runs different apps on Android devices. This virtual machine makes use of kernel’s core features like memory management and multi threading, which are in the Java language. This VM process the files in the format of .dex. There are a number of games available in the market for users. The Android applications can be written in the Java language
The electronic appliances in the home can be operated from any place within a range of 10 meters by using Bluetooth technology to control the home electronic appliances by using android phone. 8051 Microcontroller with a Bluetooth module, the wireless receive data sent from the Android Phone. From this phenomena Microcontroller can Turn OFF and ON the home appliances.
The required electrical and electronic components to build this project includes the following
- 8051 Microcontroller
- 10K resistor
- Bluetooth Module HC05
- 1000uf capacitor
- Bluetooth controller App Android app
- IC 7805
- Bulb1k resistor
- Android phone
- 10uf capacitor
HC-05 Bluetooth module will have Bluetooth serial interface module and Bluetooth adaptor. To convert serial port for a Bluetooth, serial port is used.
How to Operate the Bluetooth Module?
The rate of the new Bluetooth module in bps is 9600. Connect tx and rx to serial converter or controller and give 5 V dc regulated power supply to the module. Bluetooth module has two modes:
- Master mode
- Slave mode
For some AT commands, users can set on either mode. Module setting is done by using AT command. Some of the commands used are given: First, enter AT mode with 38400bps baud rate along by pressing En button at the Bluetooth module or else just can give a high level at EN pin. Here all commands will end with \r\n(0x0a) or enter key from keyboard.
After sending AT to the module then the module will respond as OK
- AT + NAME=xyz—Set Bluetooth Name
- AT + ROLE=0—Slave mode select
- AT + PSWD=xyz—Set Password
- AT + URAT=<Value1><Value2><Value3>—Set Baud Rate
- AT—Test Command
Eg: AT + URAT=9600
Pin Description of Accelerator
- EN—to enter in AT mode
- Tx—serial transmitting pin
- Vcc—+5V DC
- Rx—Serial Receiving pin
8051 Microcontroller is used to control the whole project. Bluetooth module is used for controlling the home appliances. Home appliances will turn OFF and ON when touch the button in the Bluetooth mobile app in Android mobile phone. Bluetooth app is downloaded from Google play store. We can use any Bluetooth app that can send data using Bluetooth.
The following apps can be used:
- Bluetooth Spp pro
- Bluetooth controller
Once it is installed in the android phone select the HC-05 Bluetooth device. For Bluetooth controller app following steps have to be
- Download and install Bluetooth Controller app.
- Turned ON mobile Bluetooth.
- Now open Bluetooth controller app
- Press scan
- Select the desired Bluetooth device, i.e. Bluetooth Module HC-05.
- Now set keys by pressing set buttons on screen
When ‘Fan On’ button is touched in a Bluetooth controller app, then the Microcontroller receives ‘1’ via Bluetooth module and then controller, Switch ‘On’ the Fan by using relay and relay driver. And when user touch ‘Fan OFF’ button in a Bluetooth controller app, then Microcontroller receives ‘2’ via Bluetooth module & then controller, Turn OFF the Fan by using a relay and relay driver.
Likewise 3,4,5,6 numbers are sent by Android Phone, when Light On/Off, TV On/Off button has been touched respectively:
|1||Fan On||Fan Turned ON|
|2||Fan OFF||Fan Turned OFF|
|3||Light ON||Light Turned ON|
|4||Light OFF||Light Turned OFF|
|5||TV ON||TV Turned ON|
|6||TV OFF||TV Turned OFF|
Circuit Diagram and Explanation
Circuit connections are very simple. Bluetooth module’s Tx and Rx pins are directly connected to the Rx and Tx pins of the microcontroller. Three 5 volt relays are used as a switch for turning ON and OFF the home appliances which are running on AC mains. And for driving relay a relay driver ULN2003 is used. TV, Light and Fan are connected at P2.3, P2.2 and P2.1 via relays and relay driver. For generating clock signal for Microcontroller an 11.0592 MHz Crystal Oscillator is used. And to provide 5V to whole circuit a 5V voltage regulator LM7805 is used
Thus, this is all about home appliance control with Bluetooth technology, which includes android mobile technology, what is a Bluetooth device, circuit diagram and explanation of home appliance control using a Bluetooth device. Furthermore, any queries regarding this article or to implement home automation projects, please comment in the comment section below.