Radio frequency (RF) operates between 30 kHz and 300 GHz. RF can flow through circuits containing capacitors and inductors, and its current can ionize air. An antenna is used to receive RF signals. RF reflects back in cables and causes standing waves. Transmitters generate RF signals using oscillators and modulators to encode information onto carrier waves, which antennas broadcast. Receivers use tuned circuits to select the desired frequency and decode the signal. The document describes an RF remote control system using an HT12E encoder and HT12D decoder to convert button presses to serial outputs and light LEDs accordingly. Breadboard circuits were constructed to transmit and receive RF signals between the encoder/transmitter and decoder/receiver.

1. Submitted By:-
Bhaskar Jyoti Dekaraja
Janmoni Medhi
Sujita Borah
Tridib Sharma

2. Introduction on Radio Frequency
 It is the rate of oscillation in the range of 30 KHz-300 GHz.
 It has the ability to flow through path containing capacitor and inductor.
 RF current can usually ionize air creating conductive path.
 To receive a radio signal antennae is used.
 When conducted by an ordinary electric cable, RF current reflects and travel back towards the source.
This condition is called Standing Wave.
 RF must be passed through transmission lines .
 RF current does not penetrate deeply into electrical conductors but tends to slow along the surface.
This is known as Skin Effect.

3. CIRCUIT DIAGRAM

4. RF Transmitter
 A radio transmitter is an electronic device which, when connected to an antenna, produces
an electromagnetic signal such as in radio and television broadcasting, two way communications
or radar
 The radio transmitter is comprised of an information signal, oscillator, and modulator.
 An LC Oscillator is a simple implementation for an oscillator, and can be used with a modulator to
modulate information signal with the oscillator and carry it to the antenna where it can broadcasted.
 The antenna transfers the radio signal to a tuner which utilizes a bandpass filter that has a high gain
in the band pass and a low gain at all other frequencies to suppress all other frequencies except the
desired frequency that contains information.

5. RF Receiver
 Radio receiver design includes the electronic design of different components of a radio receiver
which processes the radio frequency signal from an antenna
 The receiver picks up the transmitted signals using the 434Mhz receiver module.
 The receiver and transmitter must have same tuned frequency.

6. PIN diagram of Encoder and Decoder
Fig.:-
Encoder Fig.:- Decoder

7. PIN Description of Encoder

8. PIN Description of Decoder

9. HT12E Encoder and decoder
 It is an encoder IC of 2^12 series of
encoders.
 Mainly used in interfacing RF and
Infrared circuits.
 Encoders and decoders should have
same no of address and data format.
 Converts the parallel input’s into serial
output.
 HT12D is a decoder integrated circuit
that belongs to 2^12 series of decoders.
 This series of decoders are mainly used
for remote control system applications,
like burglar alarm, car door controller,
security system etc.
 HT12D converts the serial input into
parallel outputs.

10. What we have done till now
 Connected the RF modules (434MHz) in respective
Transmitter and Receiver named Bread Board circuit.
 Connected the Encoder (HT12E) and Decoder (HT12D) in
respective Transmitter and Receiver named Bread Board
circuit respectively.
 Connected the Push buttons after finding its positive and
negative terminals in the Transmitter Circuit breadboard.
 Connected the LEDs after finding its positive and negative
terminals in the Receiver Circuit breadboard.
 Given all the address ports of Encoder and Decoder ‘0’
(Grounded) input so as to match the data of transmitter
and receiver.
 Made the jumper connections in the bread board so as to
nullify the connection problems.

11.  Connected the resistors as per the circuit diagram in the encoder
and decoder.
 Given No Connection as per the circuit diagram.
 Connected the Antennas in the Transmitter and Receiver pair for
the transmission via Radio Frequency.
 And finally given the Power Supply of 5 Volt. For the functioning
of the Transmitter and Receiver pair successfully.
 A fluctuation across the terminals of the LEDs are observed when
switches are turned on and off.

12. Transmitter part

13. Receiver part

14. Thank You