L94, Remote Control Home Appliances | Without Micro-controller | RF 434MHz

Updated: Jun 6

Here, we'll learn you how to design a Remote Control Home Appliances without using any micro-controller and arduino.. Using this circuit, you can control your home appliances like, Bulb, CFL, LED, LCD, Motor etc with the help of this circuit.


RECEIVER CIRCUIT

TRANSMITTER CIRCUIT

RF MODULE (434MHz)

This module operates at radio frequency. The Radio frequency range is 30 KHz to 300 GHz. In this system, RF modules use ASK (Amplitude Shift Keying) modulation.

The chosen pair of RF Transmitter and receiver should have same frequency. The transmission speed of these modules is 1Kbps to 10Kbps.

The range of this module is approx 500ft from a center point to all direction.

RF module Pinout

  1. Antenna

  2. Ground

  3. Ground

  4. VCC (+5V)

  5. VCC (+5V)

  6. NC (Not Connected)

  7. DATA

  8. Ground

A. Antenna

B. Ground

C. Data

D. VCC (+5V)


4-CHANNEL RELAY BOARD

Relay Board Pinout

  1. Ground

  2. Input-1

  3. Input-2

  4. Input-3

  5. Input-4

  6. Vcc (+5V)

RF Remote Control Circuit Principle


When we press any key in the remote circuit, the transmitter circuit generates the corresponding RF signal and this signal is received by the receiver circuit, hence it switches ON/OFF the corresponding appliance.


A four channel encoder(HT12E)/decoder(HT12D) pair is used in this system. The input signals at the transmitter circuit are taken from the four switches and the output signals at the receiver are indicated by the four LEDs of relay board corresponding to each switch.


HT12E Encoder


This 18 Pin encoder IC is integrated 2^12 series of encoders. This IC is mainly used to interface RF and IR circuits. This IC converts 12 bit parallel to serial data. These 12 bits are divided into 4 data bits and 8 address bits.

This IC has transmitter enable pin. When trigger signal is received on this pin, the address and data bits are transmitted together. HT12E starts a 4 word transmission cycle upon receipt of enable. The transmission cycle is repeated till transmitter enable is kept low.


HT12D Decoder


This 18 Pin decoder IC converts serial input data to parallel. This IC indicates valid transmission by a high at VT (Valid Transmission) pin.

HT12D is capable to decode 12bit data (8 address bits and 4 data bits). The output data remains unchanged till the new data is received.

It is mainly used in RF and IR circuits. These decoders are mainly used for remote control applications like burglar alarm, car door alarm, security system etc.

The chosen pair of encoder and decoder for communication should have same number of address and data bits.


Advantages and Applications

  • Long distance range upto 500ft

  • control 4 appliances using a single board

  • easy to use

  • easy to design

  • low power consumption

  • can represent in school & college exhibition

  • can submit as minor project.

  • very cheap approx 500INR

NOTE: You can use this setup in different mode such as Toggle, Momentry and Latch depends on Encoder/Decoder IC

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