This document describes an electronic switch control system using radio frequency (RF) communication. A group of four students designed a remote control that can operate home appliances like fans and lights without a microcontroller. The remote contains an encoder and ASK transmitter that sends RF signals when buttons are pressed. A receiver with a decoder receives the signals and uses flip-flops and a transistor to control a relay and appliance. The system allows remote control of appliances from up to 8 meters away. Key components include HT12E/HT12D encoder/decoder chips, an ASK transmitter and receiver operating at 433MHz, and a relay to switch household power.

1. ELECTRONIC SWITCH CONTROL THROUGH
RF(RADIO FREQUENCY)
GROUP MEMBERS:
Anil Kumar Loya ME12B1002
RITESH KUMAR CE12B1019
SAHIL TAMBOLI ME12B1037
VARALA RAJATH ME12B1038
Indian Institute of Technology
Hyderabad

2. INTRODUCTION
 This is a simple type remote control by using RF communication
without microcontroller. In this project a remote has been designed for
various home appliances like fan, lights, etc. It gives lot of comfort to
the user since we can operate it by staying at one place. We can
control any of the appliances by using this remote. In this project
consist of two sections, transmitter (remote) and receiver section.
Whenever we are pressing any key in the remote it generates the
corresponding RF signals, and these signals are received by the
receiver unit. ASK transmitter and receiver is used as transmitter and
receiver. HT12E, HT12D encoders and decoders are used in this
electronic circuit.

3. The block diagram of the circuit:

4. COMPONENTS USED:
IC HT12D,HT12E,LM7805.
TRANSISTOR BC558,SL100.
ASK TRANSMITTER 433MHZ.
ASK RECEIVER 433MHZ.
PUSH TO ON SWITCH.
RELAY SWITCH.
LED (RED).
RESISTORS.
CAPACITORS.

5. REMOTE SECTION
 In remote section consist of an encoder (HT 12E) and a ASK transmitter.
The encoder generates 8 bit address and 4bit data. Whenever we press
any key in the remote the encoder generates corresponding 4bit data and
send this data by using ASK transmitter. The transmitting frequency is
433MHz. The transmitter output is up to 8mW at 433.92MHz.
RECEIVER SECTION
 At the receiver section ASK receiver is present. The receiver also operates
at 433 MHZ. It receives the datas from the transmitter. Then the decoder
(HT12D) decodes the data and it will enable the corresponding output pin.
Each output pins are connected to separate flip flops. The output of
encoder will change the state of flip flop. This output is not cable to drive a
relay directly. So we use current driver (transistor SL100). The appliance is
connected to 230v AC through the relay and appliance will start. The relay
will be re-energized when the same switch is pressed in the remote and the
state of flip flop is changed and appliance will switch-off.

6. PIN DIAGRAM OF TRANMITTER AND
RECEIVER:

7. Pin Diagram
IC HT12E:
HT12E is an encoder integrated
circuit of 2^12 series of encoders.
They are paired with 2^12 series
of decoders for use in remote
control system applications. It is
mainly used in interfacing RF and
infrared circuits. The chosen pair
of encoder/decoder should have
same number of addresses and
data format.

8. IC HT12D: Pin Diagram
HT12D is a decoder integrated
circuit that belongs to 212
series of decoders. This series
of decoders are mainly used for
remote control system
applications, like burglar alarm,
car door controller, security
system etc. It is mainly
provided to interface RF and
infrared circuits. They are
paired with 212 series of
encoders. The chosen pair of
encoder/decoder should have
same number of addresses and
data format.

9. REFERENCES:
 WWW.CIRCUITSTODAY.COM
 WWW.WIKIPEDIA.COM
THANK YOU