RF Based Home Automation System

RF based Home Automation System

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What is Home Automation


As the technologies are rapidly advancing that affects the human daily lives more flexible, particularly in controlling home appliances.

Electrical installations are the heart of every building, therefore intelligent building control absolutely ensures the safety and efficient control and eventually saves the electric power consumption and human energy.

Home automation system does the operations like lighting control and regulation, regulating HVAC (Heating, Ventilation and Air Conditioning) equipment’s, energy and load management, security and monitoring, audio/ video systems, HMI’s and other control tasks.

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Introduction to RF based Home Automation System To develop a home automation system with a RF controlled remote, houses are also

getting smarter.

As technology is advancing so houses are also getting smarter.

Modern houses are gradually shifting from conventional switches to centralized control system, involving RF controlled switches.







Functional Description:

Presently, conventional wall switches located in different parts of the house makes it difficult for the user to go near them to operate.

In order to achieve this, a RF remote is interfaced to the microcontroller on transmitter side which sends ON/OFF commands to the receiver where loads are connected.

By operating the specified remote switch on the transmitter, the loads can be turned ON/OFF remotely through wireless technology.

This circuit utilizes the RF module (Tx/Rx) for making a wireless remote, which could be used to drive an output from a distant place.

RF module, as the name suggests, uses radio frequency to send signals . These signals are transmitted at a particular frequency and a baud rate.







Block Diagram For Transmitter







Block Diagram For Receiver







Hardware Requirements: 8051 series Microcontroller Transformer Opto-isolator TRIAC Voltage Regulator Crystal Diodes Resistors Capacitors Lamps RF modules Push Buttons.

Software Requirements:

Keil compiler.







RF Transmitter and Receiver

RF modules are normally divided into three groups, RF transmitter module, RF receiver module and RF transceiver module .

433MHz ASK transmitter and receiver is used for the remote control.







Features of RF

Range in open space(Standard Conditions) : 100 Meters RX Receiver Frequency : 433 MHz RX Typical Sensitivity : 105 Dbm RX Supply Current : 3.5 mA RX IF Frequency : 1MHz Low Power Consumption Easy For Application RX Operating Voltage : 5V TX Frequency Range : 433.92 MHz TX Supply Voltage : 3V ~ 6V TX Out Put Power : 4 ~ 12 Dbm







Encoder Encoder IC (HT12E) receives parallel data in the form of

address bits and control bits.

The control signals from remote switches along with8 address bits constitute a set of 12 parallel signals.

The encoder converts the parallel inputs (from the remote switches) into serial set of signals.

These signals are serially transferred through RF to the reception point.

Transmission is enabled by providing ground topin14 which is active low.







Decoder In the receiver circuit we use RF module to get the

data and decoded by the decoder.

Decoder deliver the data into 4 bit and we use further control circuit to switch on/off.

The decoder is used after the RF receiver to decode the serial format and retrieve the original signals as out puts. These outputs can be observed on corresponding LEDs.







Opto-isolator

Opto-coupler MOC3061/63 an LED SCR type combination.

Opto coupler is a 6 pin IC.

Additionally while using this IC with microcontroller and one LED can be connected in series with IC LED to indicate when high is given from micro controller such that we can know that current is flowing in internal LED of the opto-IC.

When logic high is given current flows through LED from pin 1 to 2 .

So in this process LED light falls on SCR causing 6 & 4 to close only at the zero cross of the supply voltage.







BC547 (NPN –Transistor) The BC547 transistor is an NPN Epitaxial Silicon Transistor.

It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.

The ratio of two currents (Ic/Ib) is called the DC Current Gain of the device and is given the symbol of hfe or nowadays Beta, (β).

The current gain from the emitter to the collector terminal, Ic/Ie, is called Alpha, (α), and is a function of the transistor itself







Applications

Burglar Alarm, Smoke Alarm, Fire Alarm , Car Alarm, Security System.

Garage Door and Car Door Controllers.

Cordless telephone.

Other Remote Control System.

Wireless security systems.

Car Alarm systems.

Remote controls.

Sensor reporting.





RF Based Home Automation System

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