Communication With Modems

7/31/2019 Communication With Modems

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Makers

group

SPEED CONTROL OF DCMOTOR USING GSM MODEM


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Atmega32 microcontroller High-performance, Low-power Atmel AVR

8- bit Microcontroller.

It has32 Programmable I/O Lines and 40-pin PDIP

It operates at 2.7V - 5.5V for ATmega32Land 4.5V - 5.5V for ATmega32

It has 131 Powerful Instructions .

It has 32(8bit) General Purpose WorkingRegisters.

It gives the speed up to 16 MIPS at thefrequency of16MHz.

It has high Endurance Non-volatile

Memory segments. It has32Kbytes of In-System Self-

programmable Flash program memory

It has1024Bytes of EEPROM

It has two 8-bit Timer/Counters and One

16-bit Timer/Counter


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a e oContents

Introduction

PrincipleArchitecture

Components

- Microcontroller(Atmega 32)

-GSM Modem

-D.C Motor

-LCD

-MAX 232

-L293d

Circuit diagram

Programming & AT commands

Working


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DC Motor

Three-phase induction motors are themost common and frequently encountered

machines in industry

Simple design, rugged, low-price, easy

maintenance

Its speed depends on the frequency of the

power source

It Requires a variable-frequency power

electronic drive for optimal speed control

Run essentially as constant speed from no

load to full load

It has Wide range of power ratings:fractional horsepower to 10 MW


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Max 232 The MAX232 is an integrated circuit

that converts signals from an RS-232serial port to signals suitable for usein TTL compatible digital logiccircuits

We use Max232 IC forcommunication with modems.

It Operate With Single 5-V PowerSupply

It has two Drivers and two Receivers. The drivers provide RS-232 voltage

level outputs (approx. 7.5 V) from asingle + 5 V supply .

The receivers reduce RS-232 inputs(which may be as high as 25 V), to


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AT commands The GSM modem and the PC are wire-connected

through RS232 serial ports .They communicate withAT commands

AT commands are a set of commands that has beenstandardized to communicate with terminalequipments such as modem.

Most GSM modems support AT commands.

The most frequently used commands are:

AT+CMGS: To send a short message

AT+CMGR: To read a short message from the GSMmodule

AT+CMGL: To list SMS short messages stored inthe

GSM module


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L293d This Device is a monolithic

integrated high voltage, high

current four channel driver

designed to accept standard DTL

or TTL logic levels

It is used to drive inductive loads

(such as DC and stepping motors)

and switching power transistors

This device is suitable for use in

switching applications at

frequencies up to 5 kHz

The L293D is assembled in a 16

lead plastic package which has 4

center pins connected together


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Introduction This Project is a very good example of embedded

system as all its operations are controlled by

intelligent software inside the microcontroller.

The aim of this project is to control i.e. to ON/OFF and

speed control of different motors, the electrical orelectronic appliances connected to this system from

anywhere in the world.

Using the convenience of SMS, this project lets you

remotely control equipment by sending plain textmessages.

Many industries have been quick to make use of thistechnology, with millions of handsets currently in use.


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Acknowledgement I express my sincere regards to my project guide

for providing the necessary guidance and support,which has played a major role in assuring quality ofthe presentation.

I also express my sincere regards to our forproviding the motivation for binding up thepresentation.

My sincere regards are with BBD College for havingprovided us with the best of resources .


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Architecture Data messages

produced at one end ofthe monitoring systemand sent to remotemonitoring devices atanother end.

When a short messageis received, it can berestored to its originalindustrial form by

removing the SMS PDUhead.

The system usedrouting function of GSMnetwork to deliver a

message to another


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GSM MODEM We are using sim 300 in gsm modem

The GSM net used by cell phones

provides a low cost, long range, wireless

communication channel.

The Global System for Mobile

Communications (GSM) is the mostpopular standard for mobile phones in the

world

A modem (modulator-demodulator) is a

device that modulates an analog carrier

signal to encode digital information, and

also demodulates such a carrier signal to

decode the transmitted information.

This is a powerful GSM/GPRS Terminal

with compact and self contained unit.


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Working In this project we are using GSM technology. Major role of this project is to receive the SMS to

control the speed and direction of dc motor.

Initially the SMS is received from the person

authorized to use this setup (destination) by the GSMmodem (SIM300 MODEM) & is transferred to the

microcontroller devices kit with the help of a MAX 232

chip.

The AT commands given by the microcontroller to themodem.

The control signal from the SMS is extracted and is

used to control the devices connected to it

We have to convert the 'septets' of the phone to'octets' because the micro-controller need bytes with


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Communication With Modems

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