01-01-2013, 09:42 AM
DTMF BASED HOME APPLIANCES CONTROL
DTMF BASED HOME.docx (Size: 241.11 KB / Downloads: 44)
INTRODUCTION:
Today’s the demand for better home security systems has drifted over to a need for home automation. Not only does a home need to be secure but home appliances need a more refined control system. Home appliances should not be limited to only local control. There needs to be a simple and elegant way to avoid this type of situation and allow people the freedom of having complete control of their house from anywhere. With this fact in mind we have build a project for the home automation controls. The key to this control system will be the use of a telephone for a two way communication path to the central control unit.
With this system, it is possible to operate domestic electrical devices safety by using public or mobile phones from any places all over the world.
The basic idea of this project is to take advantage of the vast network of telephone lines and the proliferation of cell phones to extend human’s reach and possibilities. The system, through telephone networks, connects the user home appliances at home and gives him/her the ability to switch them ON or OFF. The user dials the home telephone number like an ordinary telephone call. The telephone at home rings and if nobody picks the call, then the system picks up the call. The system then asks for the password. The user enters the password. Once the password is entered, the user will be offered a voice menu and asked to choose from that menu. The user chooses an item from the menu by pressing a button on the phone keypad. Pressing a button on the phone generates a DTMF signal which, through the telephone network, will reach the system at home. The system will recognize the received signal and based on that will switch on/off the chosen appliance.
This project uses DTMF technology for the controls.
DTMF, better known as touch-tone, is a system of signal tones used in telecommunications. Applications include voice mail, help desks, telephone banking, etc.
There are twelve DTMF signals, each of which is made up of two tones from the following selection: 697 Hz, 770 Hz, 852 Hz, 941 Hz, 1209 Hz, 1336 Hz, 1477 Hz. The tones are divided
AIM & OBJECTIVE
AIM:
1.To make a CELL-PHONE operated DTMF HOME AUTOMATION SYSTEM.
2.To make a home security system.
3.To prepare remote sensing security system.
OBJECTIVE:-
In the view today society demand it is essential to made a better home security systems. Not only does a home need to be secure but home appliances need a more refined control system. Home appliances should not be limited to only local control.
From the above point of view we have tried to prepare a model for home automation control and security system.
Phone Interface:
The telephone line is hooked to the another phone attached to the system This will communicate directly with the microcontroller through the CM8870 decoder which decodes all 16 DTMF tone pairs into a four bit code.
CM8870/70C (DTMF decoder):
CM8870/70C is a Full DTMF receiver, uses less than 35mW power consumption, uses quartz crystal or ceramic resonators, has adjustable acquisition and release times, works in Industrial temperature range and is available in 18-pin DIP, 18-pin DIP EIAJ, 18-pin SOIC, 20-pin
PLCC.
ATMEL AT89C52 (Microcontroller):
he AT89C52 is a low-power, high-performance CMOS 8-bit microcomputer with 8K Flash bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 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 AT89C52 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.