05-12-2012, 02:36 PM
DTMF BASED HOME AUTOMATION
DTMF BASED HOME.doc (Size: 1.01 MB / Downloads: 48)
INTRODUCTION
CONCEPT OF EMBEDDED SYSTEM :-
A precise definition of embedded systems is not easy. Simply stated, all computing systems other than general purpose computer are embedded systems. System is a way of working, organizing or performing one or many tasks according to a fixed set of rules, program or plan.
A general-purpose definition of embedded systems is that they are devices used to control, monitor or assist the operation of equipment, machinery or plant.“ Embedded” reflects the fact that they are an integral part of the system. Embedded systems contain processing core that are either microcontrollers or digital signal processors.
It is not compulsory to have operating system in every embedded system.For small appliances such as remote control unit,air conditioner ,toys etc..there is no need to fir an operating system and we can write only the software specific to that application.for application involving complex processing,it is advisable to have an operating system.in such case you need to integrate the application software with the operating system and then transfer the entire software on to the memory chip. Once the software is transfer to the memory chip,the software will continue to run for a long time and you don’t need to reload new software.
8051 Microcontroller
The Intel 8051 is an 8-bit microcontroller which means that most available operations are limited to 8 bits. There are 3 basic"sizes"of the 8051:
Short
Standard
Extended
The Short and Standard chips are often available in DIP (dual in-line package) form, but the Extended 8051 models often have a different form factor, and are not "drop-in compatible".All these things are called 8051 because they can all be programmed using 8051 assembly language, and they all share certain features (although the different models all have their own special features). Intel refers to it as MCS – 51.A microcontroller also called an embedded controller because the microcontroller and its support circuits are often built into, or embedded in, the devices they control. A microcontroller internally consists of all features required for a computing system and functions as a computer without adding any external digital parts in it.
LEDs :
LEDs emit light when an electric current passes through them. LEDs are available in red, orange ,amber, yellow, green, blue and white. The colour of an LED is determined by the semiconductor material,not by the colouring of the 'package'.
Crystal Oscillator :
Crystal is a circuit element commonly used in the clock. The frequency of the crystal connected to the 8051 family can vary from 4MHz to 30MHz. The crystal clock frequency provide higher speed. Usually a system share a single crystal, easy to synchronize the various parts.
DC Power Supply :
The power supply section is the important one. A 0-12V/500 mA transformer is used for this purpose. The primary of this transformer is connected in to main supply through on/off switch & fuse for protecting from overload and short circuit protection. The secondary is connected to the diodes to convert 12VAC to 12V DC voltage. We are working on small microcontrollers, which are operating from 5V and requires less than 100mA for complete system.
Conclusion
This project presents a dtmf based home appliances controlling. The controller based on closed loop algorithm is designed and implemented with Atmel MCU in embedded system the domain. Experimental work has been carried out carefully. Hence we are controlling 6 home appliances controlling through DTMF technology effectively. Because now a days GSM technology became very popular, here its very easyto use for any applications with the help of 8051 controller.In all low end applications now a days we are using 8051 controllers like industrial automation and data acquisition.The Remote Automation using Networks [RAN] on test performed exceptionally well toits capability and accuracy. All the inherent parts of the circuit performed consistently. It helped us to come out with good judgment. With the features what it inherits, it seems to be advantageous to the present era.