communication with modems
TRANSCRIPT
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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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