DTMF BASED HOME APPLIANCE SYSTEM

Made by-

Daksh Raj Chopra

Contents

• Introduction

• Circuitry

• Components Used

• Block Diagram

• Circuit Diagram

• Working of the Circuit

• Applications

• Project Picture

Introduction

This project we propose a unique System mobile controlled robotutilizing Dual Tone Multi Frequency (DTMF) that is paired with awireless module to provide seamless wireless control over manydevices in a house. This user console has many keys, eachcorresponding to the device that needs to be activated. The encoderencodes the user choice and sends via a FM transmitter. The FMreceiver receives the modulated signal and demodulates it and the userchoice is determined by the DTMF decoder. Based upon this therequired appliance is triggered.

Circuitry

• DTMF DECODER

• MICROCONTROLLER

• EXCESS CONTROL CIRCUIT

• AUTOMATIC ON THROUGH OUTER PHONE

DTMF Decoder

8051 Microcontroller

The AT89S51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash Programmable and Erasable Read Only Memory (PEROM). The device is manufactured using Atmel’s high density non-volatile memory technology and is compatible with the industry standard MCS-51™ instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89S51 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications. The AT89S51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, five vector two-level interrupt architecture, a full duplex serial port, and on-chip oscillator and clock circuitry.

8051 Microcontroller

• Compatible with MCS-51™ Products

• 4K Bytes of In-System Reprogrammable Flash Memory

– Endurance: 1,000 Write/Erase Cycles

• Fully Static Operation: 0 Hz to 24 MHz

• Three-Level Program Memory Lock

• 128 x 8-Bit Internal RAM

• 32 Programmable I/O Lines

• Two 16-Bit Timer/Counters

• Six Interrupt Sources

• Programmable Serial Channel

• Low Power Idle and Power Down Modes

Components Used

• Microcontroller - AT89S52

• DTMF Decoder – MT8870

• ULN 2003

• Relay

• Led

• Resistors

• Pull – Up Resistor

• Capacitors

Components Used

• Crystal Oscillator

• Push Button

• Mic

• Voltage Regulator

• Bulb Holders

• Bulbs

• Plug

• AC Power Supply

Block Diagram

Circuit

Working

• IN this project our first part is DTMF decoder. The DTMF IC receivesthe DTMF pulse and then converts it into binary coded decimal. PinNo. 18 of the IC is connected to positive supply. In this circuit we use+5 volt regulated power supply for the smooth working. DTMF signalis applied to the pin No. 2 and 3 of the IC through resistor andcapacitor network. Capacitor of 0.1 uF works as a dc blockingcapacitor. Pin No. 5, 6, 9 is connected to the Ground pin. Pin No. 7and 8 is connected to the 12.095 crystal. Pin No. 16 and 17 isconnected to RC network work as an auto reset, when we switch onthe power supply.

• BCD output is available on the pin No 11, 12, 13, 14 and this output isconnected to the microcontroller 89C51.

Working

• Our next part of the circuit is 89C51. 89C51 is a 40 pin IC. Pin No. 40of the IC is connected to the positive supply. Pin No. 9 is rest pin. Onecapacitor and resistor network is connected to pin No 9. Thismicrocontroller has a total of four input output ports each 8 bit wide.

• Another pins of the port 3 is also connected for another useful uses.

P3.3 Acknowledge of code lock

P3.4 Time indication of the code lock

P3.5 Led indication of sound output for on/off signal

P3.2 Output frequency for opto-coupler input.

Industry Applications

• The need for the above project was that this project firstly it saves our time. If you are stuck in traffic you can switch on your microwave oven on slow cooking mode. By the time you reach your home your food will be ready. You don’t have go to each room to check whether the lights are on/off. You can do with a click of single button. Secondly, it save our money in the long run. There are some appliances like a television which we switch off but not its power supply. There is a Led still glowing in it which uses electricity. If we have this television attached to our project then we can switch off its power supply whenever we want and there are many other devices like this. Thirdly, it for self-maintenance and security. Security as in if we by chance forgot to switch off any of lights then we can switch off from our phones. Lastly, we all know that all this will make our life easy and trouble free.

• Industrial applications for the project made are that one can control home appliances from anywhere in the world even we are sitting a cup of tea in United States of America. Secondly, it reduces wastage of electricity as discussed earlier that if we forget to switch off the lights. Last but not the least it is very low cost compared to other technologies like GSM.

Project Picture

Thank You

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