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Project Report on DC Motor counter
             by GSM


This is to certify that_________________________ Roll No. is
________ completed his project work on the topic “Dc motor
control by GSM” as a part of their curriculum of Diploma in
Electrical Engineering at M.S.University of Baroda for the term
ending in 2011-12.

MR. M.M. PATEL                      Head of Department


We hereby take the opportunity to express our deep sense of
gratitude to Mr. M.M. Patel, Assignment professor, Electrical &
Electronic Engineering department for his kind support timely
guidance given to us for reaching for destination with perfection.
We are thankful to him for his suggestions and ideas to make this
project work even better.

We are very much thankful to head of electrical & electronics
engineering department, who permitted to us work on the topic and
extended his kind support and help for the same. The enthusiasm
shown by him in our project proved to be a great source of
inspiration. We are also grateful to Mr. S.B. Dave for his help.

We are also thankful to all the teaching and non-teaching staff
members and friend who helped us directly and indirectly for the
successful completion of this work.
                                                      Vijay T. Patel
                                                    Alpesh M. Patel





















             Our academic final year Electrical Project “DC
Motor control by GSM” .This Project must important for many
types of industry and plant machinery. This GSM technology
thorough fully DC motor control like speed and direction change.
     Our project operates with totally microcontroller based. This
project main part of microcontroller and second main part of GSM
modem. this modem thorough dc motor control by any mobile as
per SMS code


A Brief History of GSM
The GSM story starts in 1982, when the Confederation of
European Posts and Telecommunications (CEPT) formed the
Group Special Mobile (GSM) to design a pan-European mobile
technology. The European Commission endorsed the GSM Project
in 1984. One year later, France, Italy, the U.K. and West Germany
signed a joint agreement to develop GSM. Early 1987 brought an
agreement on the basic parameters of the GSM standard, and the
GSM Memorandum of Understanding (MoU) was promoted. A
total of 15 members from 13 countries committed to deploying
GSM through the Pan European Digital Conference. Validation
trials in 1988 proved that GSM technology was viable, and in 1989
the Group Special Mobile became a technical committee within the
European Technical Standards Institute (ETSI), which helped to
define GSM as an internationally accepted digital cellular
telephony standard.
Network operator Radiolinja in Finland placed the first GSM call
in 1991. The following year, Telstra Australia became the first
non-European operator to sign the GSM MoU, and Telecom

Finland and Vodafone (UK) signed the first international roaming
agreement. During the same year, the first SMS using GSM was
By 1993, 32 networks were using GSM in 18 different countries or
territories, and the first true hand terminals meeting the standard
were launched commercially. By 1994, there were more than a
hundred GSM operators and a million subscribers around the
world. Within a year those figures rose to 117 networks and ten
million unique users. By 1996, the first GSM networks were
deployed in Russia and China, while prepaid GSM SIM cards
appeared in Italy. During this same year, 167 networks were
officially using GSM in 94 countries and GSM had fifty million
subscribers. In 1997 the USA alone had 15 GSM networks, and by
1998 there were over a hundred million GSM subscribers globally.
In 1999 GSM gained another layer, called the Wireless Application
Protocol (WAP). WAP was viewed as the advanced data
companion to GSM and other wireless technologies. WAP trials
began in France and Italy the same year, and next-generation
(2.5G) GPRS systems were deployed for the first time. In February

                 AIM OF PROJECT

This project with our main aim of easily understands Hi-tech
warless GSM Mobile communication technology. and our next
junior student also grow technical knowledge our project.














These projects operate for following under steps interactions.

1. Put battery proper and power switch turn on.

2. Insert sim card in GSM modem.

3. Two minutes hold for network set with Mobile tower.

4. sent SMS with proper key wed for proper work.


This project very useful for many types of industry plant and
machine. Because this GSM technology thorough DC motor speed
counterollig and motor direction change with forward and reverse
by only one SMS. This project all function work with differential
SMS code like speed increase H1 speed decries H2 motor forward
FF and reverse FR.    This all data send to any mobile and receive
by GSM receiver unit.
    This project fully microcontroller base working and
monitoring by GSM modem. These technologies have not range
limit because worldwide communication with satellite bitewing
mobile and GSM. This project operates on 12v dc battery so not
required have electrical supply.

 This project technology already use in home appliances and
security system.


          These projects have main advantage as under.

1. Motor speed controlling.

2. Motor direction fevered and reverse also possible.

3. Worldwide rage by GSM.

4. Note risked of electrical shock.

5.   GSM base worldwide data send in mobile

     Reliable and easy to in stole.

     Occasionally GSM system will be failed then manual
     operating possible.


This project only one disadvantage like constant battery charge and
need tower network for GSM CONTROLLING system.

                PRINCIPAL OF PROJECT

This project working principal following ‘C’ programming and
work with microcontroller. And analog data connect with
controller for serial communication by ADC protocol. Project
satellite interfusing by GSM protocol

           Voice navigation Project. for our academic

Something different project in our academic final year with survey
different type of project like as under:
   Sine Wave Inverter
   Online UPS
   Digital Stabilizer
   DC Drive
   Frequency Controller
   Remote Control Switch

Are all projects for up listing subject related website, books and all
project groups with discuss after we decide up listing all project is
a very higher costing and raw material is also not easily available
in local market to much time consumption job hence we avoid
upper listing project and we decide make a Mobil operated DC
motor speed controlling by GSM system project.

DC motor speed controlling by GSM. This project not required
heavy engineering workshop. Raw material is also easily available
in local market. This project information is also available in
website and other book. So these projects for we discuss with our
project group and our collage friend circle. Our professor and our
HOD with discussion a project of ‘DC motor speed controlling
by GSM”. Finally we get the permission from our collage then
after we start designing and assembly of these projects.

               LIST OF MATERIAL

         We structured our project for we survey some type of
material and it project assembly for we make raw material list our
project for required material list as under.
No. Particular
 1   Microcontroller
 2   ADC 0808
 3   IC LM 7414
 4   Regulator IC 7805
 5   IC ULN.2003
 6   Mosfet IRFZ44n
 9   12v battery
11 LCD 16-2
12 12Mhz Xtal
13 1000/25. 100/16v capacitor.
14 RELAY 10amp
15 Piezo BUZZER
16 capacitor
17 Variable Pot etc. 10k

               COST OF MATERIAL

We make air project for required air material after. We survey
electronics market in air requirement material cost. It material cost
as under
No. Particular
 1   Microcontroller
 2   ADC 0808
 3   IC LM 7414
 4   Regulator IC 7805
 5   IC ULN.2003
 6   Mosfet IRFZ44n
 9   12v battery
11 LCD 16-2
12 12Mhz Xtal
13 1000/25. 100/16v capacitor.
14 RELAY 10amp
15 Piezo BUZZER
16 capacitor
17 Variable Pot etc. 10k




  Network connect

    GSM message go

   Motor controlling

  GSM message go



                CIRCUIT DIAGRAM

Controller interfacing with LCD, ADC and Relay driver

ADC, MAX & Power Supply:


This Project all function operates with microcontroller technology
because this project has all system operates by programming logic,
this project work with 8bit and LCD operate on 4bit logic.
    This project has GSM communication for use readymade GSM
modem RX/TX. Wireless modem.
Details working discuss in component study as under chapters.

      DC motors are widely used in industrial applications. In this
regard controlling the speed in wide range is another aspect. For
this purpose, here is an abstract of the project

Electrical is the most valuable and precious one for this universe.
In this the motor plays an important role. Hence we want to control
the motor for our requirements.

    The aim of this project is to control the speed of the DC motor.
Generally, DC motors are applicable for effective speed control
and high starting torque applications like traction, lift, etc.

    Basically DC motor speed control is done by voltage control,
armature resistance control and flux control methods. But in this

project we are control the speed of the DC motor by Pulse Width
Modulation (PWM) technique. From this method we can obtain a
smooth speed variation without reducing the starting torque of the

   PWM technique also eliminates harmonics. Mat lab tools are
available for DC machine. By using this, a mat lab using semolina
of the speed control of motor can be done in a mat lab environment
and also can be verified by experiments.

The PWM circuit requires a steadily running oscillator to operate. U1a
and U1d form a square/triangle waveform generator with a frequency
of around 400 Hz.

U1c is used to generate a 6 Volt reference current which is used as a
virtual ground for the oscillator, this is necessary to allow the
oscillator to run off of a single supply instead of a +/- voltage dual

U1b is wired in a comparator configuration and is the part of the
circuit that generates the variable pulse width. U1 pin 6 receives a
variable voltage from the R6, VR1, R7 voltage ladder. This is
compared to the triangle waveform from U1-14. When the waveform
is above the pin 6 voltage, U1 produces a high output. Conversely,

when the waveform is below the pin 6 voltage, U1 produces a low
output. By varying the pin 6 voltage, the on/off points are moved up
and down the triangle wave, producing a variable pulse width.
Resistors R6 and R7 are used to set the end points of the VR1
control, the values shown allow the control to have a full on and a full
off setting within the travel of the potentiometer. These part values
may be varied to change the behavior of the potentiometer.

Finally, Q1 is the power switch, it receives the modulated pulse width
voltage on the gate terminal and switches the load current on and off
through the Source-Drain current path. When Q1 is on, it provides a
ground path for the load, when Q1 is off; the load's ground is floating.
Care should be taken to insure that the load terminals are not
grounded or a short will occur.

The load will have the supply voltage on the positive side at all times.
LED1 gives a variable brightness response to the pulse width.
Capacitor C3 smooth out the switching waveform and removes some
RFI, Diode D1 is a flywheel diode that shorts out the reverse voltage
kick from inductive motor loads.

In the 24 Volt modes, regulator U2 converts the 24 Volt supply to 12
Volts for running the PWM circuit, Q1 switches the 24 Volt load to
ground just like it does for the 12 Volt load. See the schematic for
instructions on wiring the circuit for 12 Volts or 24 Volts.

When running loads of 1 amp or less, no heat sink is needed on Q1,
if you plan to switch more current, a heat sink with thermal grease is
necessary. Q1 may be replaced with a higher current device; suitable
upgrades include the IRFZ34N, IRFZ44N, or IRFZ48N. All of the

current handling devices switch S1, fuse F1, and the wiring between
the FET, power supply, and load should be rated to handle the
maximum load current.

This circuit will work as a DC lamp dimmer, small motor controller,
and even as a small heater controller. It would make a great speed
control for a solar powered electric train. The circuit has been tried
with a 5 Amp electric motor using and IRFZ34N FET and worked ok,
D1 may need to be replaced with a faster and higher current diode
with some motors. The circuit should work in applications such as a
bicycle motor drive system, if you experiment with this, be sure to
include an easily accessible emergency power disconnect switch in
case the FET shorts out and leaves the circuit full-on.

Wire the circuit for 12 Volts or 24 Volts as per the schematic, connect
the battery to the input terminals, and connect the load to the output
terminals, be sure not to ground either output terminal or anything

connected to the output terminals such as a motor case. Turn the
potentiometer knob back and forth, the load should show variable
speed or light.

       PWM or pulse width modulation refers to the concept of
rapidly pulsing the digital signal of a wire to simulate a varying
voltage on the wire. This methods is commonly use for driving
motors, heaters, or lights in varying intensities or speeds.
     A few terms are associated with PWM:

        1. Period - how long each complete pulse cycle takes
        2. Frequency - how often the pulses are generated. This
value is typically specified in
          Hz (Cycles per seconds).

         3. Duty cycle - refers to the amount of time in the period
that the pulse is active .
           high. Duty cycle is typically specified as a percentage of
the full period.

    In the above diagram, the duty cycle is shown at 50%. The pink
line shows the average output and you can see that at 50% duty
cycle, the output averages is roughly 6v or 50% of full power.
Below is a diagram of what a 25% duty cycle PWM signal looks


      The human ear can hear frequencies up to roughly 20 kHz.
When using PWM at frequencies below this , the device being
driven can often be heard to buzz. Higher frequencies avoid this.


       When controlling motors, much greater PWM efficiency is
achieved at frequencies above 20-30 kHz. This is because the
current (induction) in the windings of the motors doesn't greater
chance to collapse and leave the motor when the OFF- period is
short. The collapse of this induction field takes some time; driving
the motors at high PWM frequencies keeps this induction current
in the motors at all times, resulting in much higher efficiencies.

PWM control is a powerful technique for

Driving analog circuits with digital outputs.

Pulse width modulation (PWM) is a powerful technique for
controlling analog circuits with a processor's digital outputs. PWM
is employed in a wide variety of applications, ranging from
measurement and communications to power control and


       An analog signal has a continuously varying value, with
infinite resolution in both time and magnitude. A nine- volt battery
is an example of an analog device, in that its output voltage is not
precisely 9V , changes over time, and can take any real- numbered
value. Similarly, the amount of current drawn from a battery is not
limited to a finite set of possible values. Analog signals are
distinguishable from digital signals because the latter always take

values only from a finite set of predetermined possibilities, such as
the set {0V, 5V}.
        Analog voltages and current can be used to control things
directly, like the volume of a car radio; a knob is connected to a
variable resistor. As you turn the knob, the resistance goes up or
down. As that happens, the current flowing through the resistor
increases or decreases. This change the amount of current driving.
An analog circuit is one, like the radio, whose output is linearly
proportional to its input.
        As intuitive and simple as analog control may seem, it is
not always economically attractive r otherwise practical. For one
thing, analog circuits tend to drift over time and can, therefore, be
very difficult to tune. Precision analog circuits, which solve that
problem, can be very large, heavy (just think of older home stereo
equipment), and expensive. Analog circuits can also get very hot;
the power dissipated is proportional to the voltage across the active
elements multiplied by the current through them. Analog circuitry
can also be sensitive to noise. Because of its infinite resolution,
any perturbation or noise on an analog signal necessarily changes
the current value.


        By controlling analog circuits digitally, system costs and
power consumption can be drastically reduced. What's more, many
microcontrollers     and DSPs already include on - chip PWM
controllers, making implementation easy.
        In a nutshell, PWM is a way of digitally encoding analog
signal levels. Through the use of high- resolution counters, the
duty cycle of a square wave is modulated to encode a specific
analog signal level. The PWM signal is still digital because, at any
given instant of time, the full DC supply is either fully on or fully
off. The voltage or current source is supplied to the analog load by

means of a repeating series of on and off pulses. The on- time is
the time during which the DC supply is applied to the load, and the
off-time is the period during which that supply is switched off.
Given a sufficient bandwidth, any analog value can be encoded
with PWM.
         Figure 1 shows three different PWM signals. Figure 1a
shows a PWM output at a 10% duty cycle. That is, the signal is on
for 10% of the period and off the other 90%. Figures 1b and 1c
show PWM outputs at 50% and 90% duty cycles, respectively.
These three PWM outputs encode three different analog signal
values, at 10%, 50%, and 90% of the full strength. If, for example,
the supply is 9V and the duty cycle is 10%, a 0.9V analog signals

           Figure 2 shows a simple circuit that could be driven
using PWM. In the figure, a 9V battery powers an incandescent
light bulb. If we closed the switch connecting the battery and lamp

for 50 ms, the bulb would receive 9V during that interval. If we
then opened the switch for the next 50 ms, the bulb would receive
0V. If we repeat this cycle 10 times a second, the bulb will be lit as
through it were connected to a 4.5V battery (50% of 9V). We say
that the duty cycle is 50% and the modulating frequency is 10 Hz.

         Most loads, inductive and capacitative a like, require a
much higher modulating frequency than 10 Hz. Imagine that our
lamp was switched on for five seconds, then off for five seconds,
then on again. The duty cycle would still be 50%, but the bulb
would appear brightly lit for the first five seconds and off for the
next. In order for the bulb to see a voltage of 4.5 volts, the cycle
period must be short relative to the load's response time to a
change in the switch state. To achieve the desired effect of a
dimmer (but always lit) lamp, it is necessary to increase the
modulating frequency. The same is true in other applications of
PWM. Common modulating frequencies range from 1 kHz to 200


   One additional advantage of pulse width modulation is that the
pulses reach the full supply voltage and will produce more torque
in a motor by being able to overcome the internal motor resistances
more easily. Finally, in a PWM circuit, common small
potentiometers may be used to control a wide variety of loads
whereas large and expensive high power variable resistors are
needed for resistive controllers.


The main Disadvantages of PWM circuits are the added
complexity and the possibility of generating radio frequency
interference (RFI). RFI may be minimized by locating the
controller near the load, using short leads, and some cases, using
additional filtering on the power supply leads. This circuit has
some RFI by passing and produced minimal interference with an
AM radio that was located under a foot away. If additional filtering
is needed, a car radio line choke may be placed in series with the
DC power input, be sure not to exceed the current rating of the
choke. The majority of the RFI will come from the high current
path involving the power source, the load, and the switching FET,

                  Future Development

Future development this project well use of microwave or VHF

         This project will be future development possible with
PLC control and computer interfacing control is both technologies
can be used on abroad or international companies.

      Component Study

+12, +5 volt power supply circuit:

            LCD 16x2 interfacing circuit
Microcontroller – AT89S52

      RS           P0.0
      RW           GND
      ENB          P0.1
      D0           Not Connect
      D1           Not Connect
      D2           Not Connect
      D3           Not Connect
      D4           P0.2
      D5           P0.3
      D6           P0.4
      D7           P0.5

   Microcontroller with uln interfacing circuit

ADC interfacing circuit

D0-D7    P2.0-P2.7
ALE      P3.3
OE       P0.7
SC       P3.4
EOC      P3.2
CLK      P0.6
ADDR_A   P3.7
ADDR_B   P3.6
ADDR_C   P3.5

LCD display 16x2:

This is a basic 16 character by 2 line display. Black text on Green
background. Liquid crystal display is very important device in
embedded system. It offers high flexibility to user as he can
display the required data on it.
16 Characters x 2 Lines
5 x 7 Dots with Cursor
Built in Controller
+5v Power Supply
1/16 Duty Circle

                            Pin Details:
Character LCDs use a standard 14-pin interface and those with
backlights have 16 pins. The pin outs are as follows:

  1. Ground
  2. VCC (+3.3 to +5V)
  3. Contrast adjustment (VO)
  4. Register Select (RS). RS=0: Command, RS=1: Data
  5. Read/Write (R/W). R/W=0: Write, R/W=1: Read
  6. Clock (Enable). Falling edge triggered
  7. Bit 0 (Not used in 4-bit operation)
  8. Bit 1 (Not used in 4-bit operation)

  9. Bit 2 (Not used in 4-bit operation)
  10.      Bit 3 (Not used in 4-bit operation)
  11.      Bit 4
  12.      Bit 5
  13.      Bit 6
  14.      Bit 7
  15.      Backlight Anode (+)
  16.      Backlight Cathode (-)

                         LCD Interfacing:
In this tutorial i will show you how to interface 16x2 LCD with
micro-controller. 16x2 means there are two rows and each row
contains maximum 16 characters.
                         Basic Connection:
Applies 5v to pin 2 and gnd to pins 1 & 5. Use variable resistor at
pin 3 to set contrast. Pins 7 to 14 are the data pins, used to send/rec
data. Pin 6 is of enable; every time when you write to LCD you
should have to give high to low, to this pin. Pin 4 is register select
pin use to give commands like clear, home etc.

                          Block Diagram:

                    89s52 Microcontroller:

A microcontroller is a single chip that contains the processor (the
CPU), non-volatile memory for the program (ROM or flash),

volatile memory for input and output (RAM), a clock and an I/O
control unit. Also called a "computer on a chip," billions of
microcontroller units (MCUs) are embedded each year in a myriad
of products from toys to appliances to automobiles. For example, a
single vehicle can use 70 or more microcontrollers. The hardware
is driven by a set of program instructions, or software. Once
familiar with hardware and software, the user can then apply the
microcontroller to the problems easily.

                      Description of 89s52:

The AT89S52 is a low-power, high-performance CMOS 8-bit
microcontroller with 8K bytes of in-system programmable Flash
memory. The device is manufactured using Atmel’s high-density
nonvolatile memory technology and is compatible with the
industry-standard 80C51 instruction set and pin out. 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 in-system programmable
Flash on a monolithic chip, the Atmel AT89S52 is a powerful
microcontroller, which provides a highly flexible and cost-
effective solution to many, embedded control applications. The
AT89S52 provides the following standard features: 8K bytes of

Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data
pointers, three 16-bit timer/counters, a six-vector two-level
interrupt architecture, a full duplex serial port, on-chip oscillator,
and clock circuitry. In addition, the AT89S52 is designed with
static logic for operation down to zero frequency and supports two
software selectable power saving modes. The Idle Mode stops the
CPU while allowing the RAM, timer/counters, serial port, and
interrupt system to continue functioning. The Power-down mode
saves the RAM con-tents but freezes the oscillator, disabling all
other chip functions until the next interrupt.
                           Pin Diagram:
The pin diagram of the 89S52 shows all of the input/output pins
unique to microcontrollers:

The   following    are   some     of    the   capabilities   of   89S52
* Internal ROM and RAM
* I/O ports with programmable pins
* Timers and counters
* Serial data communication
The 89S52 architecture consists of these specific features:
* 16 bit PC &data pointer (DPTR)
* 8 bit program status word (PSW)
* 8 bit stack pointer (SP)
* Internal ROM 4k
* Internal RAM of 128 bytes.
* 4 register banks, each containing 8 registers
* 80 bits of general purpose data memory
* 32 input/output pins arranged as four 8 bit ports: P0-P3
* Two 16 bit timer/counters: T0-T1
* Two external and three internal interrupt sources Oscillator and
clock circuits.
                             Block Diagram:
The block diagram provided by Atmel in their datasheet showing
the architecture the 89S52 device can seem very complicated, and

since we are going to use the C high level language to program it, a
simpler architecture can be represented as the figure.
This figure shows the main features and components that the
designer can interact with. You can notice that the 89S52 has 4
different ports, each one having 8 Input/output lines providing a
total of 32 I/O lines. Those ports can be used to output DATA and
orders do other devices, or to read the state of a sensor, or a switch.
Most of the ports of the 89S52 have 'dual function' meaning that
they can be used for two different functions: the first one is to
perform input/output operations and the second one is used to
implement special features of the microcontroller like counting

Pulses, interrupting the execution of the program according to
external events, performing serial data transfer or connecting the
chip to a computer to update the software.
Each port has 8 pins, and will be treated from the software point of
view as an 8-bit variable called 'register', each bit being connected
to a different Input/output pin. You can also notice two different
memory types: RAM and EEPROM. Shortly, RAM is used to store
variable during program execution, while the EEPROM memory is
used to store the program itself, that's why it is often referred to as
the 'program memory'. The memory organization will be discussed
in detail later.

The special features of the 89S52 microcontroller are grouped in
the blue box at the bottom of figure. At this stage of the tutorial, it
is just important to note that the 89S52 incorporates hardware
circuits that can be used to prevent the processor from executing
various repetitive tasks and save processing power for more
complex calculations. Those simple tasks can be counting the
number of external pulses on a pin, or generating precise timing



            ratio metrically or with 5 VDC or analog span adjusted
voltage reference
                    -scale adjust required
    -channel multiplexer with address logic
           CC   input range
                         oltage level specifications



The ADC0808, ADC0809 data acquisition component is a
monolithic CMOS device with an 8-bit analog-to-digital converter,
8-channel multiplexer and microprocessor compatible control
logic. The 8-bit A/D converter uses successive approximation as
the conversion technique. The converter features a high impedance
chopper stabilized comparator, a 256R voltage divider with analog
switch tree and a successive approximation register. The 8-channel
multiplexer can directly access any of 8-single-ended analog

The device eliminates the need for external zero and full-scale
adjustments. Easy interfacing to microprocessors is provided by
the latched and decoded multiplexer address inputs and latched
TTL TRI-STATE outputs.

The design of the ADC0808, ADC0809 has been optimized by
incorporating the most desirable aspects of several A/D conversion
techniques. The ADC0808, ADC0809 offers high speed, high
accuracy, minimal temperature dependence, excellent long-term
accuracy and repeatability, and consumes minimal power. These
features make this device ideally suited to applications from
process and machine control to consumer and automotive

applications. For 16-channel multiplexer with common output
(sample/hold port).

Key Specification

           Resolution              8 Bits

           Total Unadjusted Error ±½ LSB and ±1 LSB

           Single Supply           5 VDC

           Low Power               15 mW

           Conversion Time         100 μs

               Pin Description
Number                   Description
  1                IN3 - Analog Input 3
  2                IN4 - Analog Input 4
  3                IN5 - Analog Input 5
  4                IN6 - Analog Input 6
  5                IN7 - Analog Input 7
  6             START - Start Conversion
  7             EOC - End Of Conversion
  8           2(-5) - Tri-State Output Bit 5
  9             OUT EN - Output Enable
  10                     CLK - Clock
  11              Vcc - Positive Supply
  12     Vref+ - Positive Voltage Reference Input

13                GND - Ground
14         2(-7) - Tri-State Output Bit 7
15         2(-6) - Tri-State Output Bit 6
16   Vref- - Voltage Reference Negative Input
17         2(-8) - Tri-State Output Bit 8
18         2(-4) - Tri-State Output Bit 4
19         2(-3) - Tri-State Output Bit 3
20         2(-2) - Tri-State Output Bit 2
21         2(-1) - Tri-State Output Bit 1
22         ALE - Address Latch Enable
23           ADD C - Address Input C
24           ADD B - Address Input B
25           ADD A - Address Input A
26             IN0 - Analog Input 0
27             IN1 - Analog Input 1
28             IN2 - Analog Input 2

    Hex Inverter with Schmitt Trigger

General Description:
This device contains six independent gates each of which performs
the logic INVERT function. Each input has hysteresis which
increases the noise immunity and transforms a slowly changing
input signal to a fast changing, jitter free output.

Schmitt Waveform Generators
Simple Waveform Generators can be constructed using basic
Schmitt trigger action inverters such as the TTL 74LS14. This
method is by far the easiest way to make a basic astable waveform
generator. When used to produce clock or timing signals, the
astable multivibrator must produce a stable waveform that switches
quickly between its "HIGH" and "LOW" states without any
distortion or noise, and Schmitt inverters do just that. We know
that the output state of a Schmitt inverter is the opposite or inverse

to that of its input state, (NOT gate principles) and that it can
change state at different voltage levels giving it "hysteresis".
Schmitt inverters use a Schmitt trigger action that changes state
between an upper and a lower threshold level as the input voltage
signal increases and decreases about the input terminal. This upper
threshold level "sets" the output and the lower threshold level
"resets" the output which equates to logic "0" and logic "1"
respectively for an inverter. Consider the circuit below.
Schmitt Inverter Waveform Generator

is simple waveform generator circuit consists of a single TTL
74LS14 Schmitt inverter logic gate with a capacitor, C connected
between its input terminal and ground, (0v) and the positive
feedback required for the circuit to oscillate being provided by the
feedback resistor, R. So how does it work. Assume that the charge
across the capacitors plates is below the Schmitt's lower threshold
level of 0.8 volt (Datasheet value). This therefore makes the input
to the inverter at a logic "0" level resulting in a logic "1" output

level (inverter principals). One side of the resistor R is now
connected to the logic "1" level (+5V) output while the other side
of the resistor is connected to the capacitor, C which is at a logic
"0" level (0.8v or below). The capacitor now starts to charge up in
a positive direction through the resistor at a rate determined by the
RC time constant of the combination.
When the charge across the capacitor reaches the 1.6 volt upper
threshold level of the Schmitt trigger (datasheet value) the output
from the Schmitt inverter rapidly changes from a logic level "1" to
a logic level "0" state and the current flowing through the resistor
changes direction. This change now causes the capacitor that was
originally charging up through the resistor, R to begin to discharge
itself back through the same resistor until the charge across the
capacitors plates reaches the lower threshold level of 0.8 volts and
the inverters output switches state again with the cycle repeating
itself over and over again as long as the supply voltage is present.
So the capacitor, C is constantly charging and discharging itself
during each cycle between the inputs upper and lower threshold
levels of the Schmitt inverter producing a logic level "1" or a logic
level "0" at the inverters output. However, the output waveform is
not symmetrical producing a duty cycle of about 33% or 1/3 as the
mark-to-space ratio between "HIGH" and "LOW" is 1:2
respectively due to the input gate characteristics of the TTL

inverter. The value of the feedback resistor, ( R ) MUST also be
kept low to below 1kΩ for the circuit to oscillate correctly, 220R to
470R is good, and by varying the value of the capacitor, C to vary
the frequency. Also at high frequency levels the output waveform
changes shape from a square shaped waveform to a trapezoidal
shaped waveform as the input characteristics of the TTL gate are
affected by the rapid charging and discharging of the capacitor.
The frequency of oscillation for Schmitt Waveform Generators is
therefore given as:

With a resistor value between: 100R to 1kΩ, and a capacitor value
of between: 1nF to 1000uF. This would give a frequency range of
between 1Hz to 1MHz, (high frequencies produce waveform
Generally, standard TTL logic gates do not work too well as
waveform generators due to their average input and output
characteristics, distortion of the output waveform and low value of
feedback resistor required, resulting in a large high value capacitor
for low frequency operation. Also TTL oscillators may not
oscillate if the value of the feedback capacitor is too small.
However, we can also make Astable Multivibrators using better

CMOS logic technology that operate from a 3V to 15V supply
such as the CMOS 40106B Schmitt Inverter.


Crystal oscillators can be manufactured for oscillation over a wide
range of frequencies, from a few kilohertz up to several hundred
megahertz. Many applications call for a crystal oscillator
frequency conveniently related to some other desired frequency, so
hundreds of standard crystal frequencies are made in large
quantities and stocked by electronics distributors. Using dividers,
frequency and phase locked loop circuits; it is practical to derive a
wide range of frequencies from one reference frequency.

     3-Terminal Positive Voltage Regulators


Output current in excess of 0.5A

No external components

Internal thermal overload protection

Internal short circuit current-limiting

Output transistor safe-area compensation

Available in TO-220, TO-39, and TO-252 D-PAK packages

Output voltages of 5V, 12V, and 15V


The LM78MXX series of three-terminal positive voltage
regulators employ built-in current limiting, thermal shutdown, and
safe-operating area protection which make them virtually immune
to damage from output overloads.

With adequate heat sinking, they can deliver in excess of 0.5A
output current. Typical applications would include local (on-card)
regulators which can eliminate the noise and degraded
performance associated with single-point regulation.
7805 Regulator Circuit

If you want to build a small power supply +5 V, the 7805
regulator is a great choice, especially for experiments with digital
circuits because the type of IC is widely available in the market.
This IC features over-heating protection, stops supplying current in
case of excess heat.
This circuit can provide +5 V output at about 150 mA current, but
can be increased to 1 A when good cooling is added to the 7805
regulator IC.
7805 Regulator Circuit Diagram

The capacitors must have enough high voltage rating to safely
handle the input voltage feed to circuit. The 7805 regulator circuit
is very easy to build for example into a piece of overboard.

7805 Regulator Circuit

Modification Output Current and Voltages

If you need a current output of more than 150 mA, please update
the output current up to 1A. Change the transformer you use to the
transformer that has a current rating greater than ever. Do not
forget to put the heat sink on the 7805 IC.

If you need a voltage output greater than +5 V, please modify the
circuit by replacing the 7805 IC to a different output voltage
from regulator 78xx ICs. You must remember it for working
properly. That at least 3V input greater than regulator output
voltage you need for your 7805 regulator.

                       Relay construction

An electric current through a conductor will produce a magnetic
field at right angles to the direction of electron flow. If that
conductor is wrapped into a coil shape, the magnetic field
produced will be oriented along the length of the coil. The greater
the current, the greater the strength of the magnetic field, all other
factors being equal:

Inductors react against changes in current because of the energy
stored in this magnetic field. When we construct a transformer
from two inductor coils around a common iron core, we use this
field to transfer energy from one coil to the other. However, there
are simpler and more direct uses for electromagnetic fields than the
applications we've seen with inductors and transformers. The
magnetic field produced by a coil of current-carrying wire can be
used to exert a mechanical force on any magnetic object, just as we
can use a permanent magnet to attract magnetic objects, except that
this magnet (formed by the coil) can be turned on or off by
switching the current on or off through the coil.

If we place a magnetic object near such a coil for the purpose of
making that object move when we energize the coil with electric
current, we have what is called a solenoid. The movable magnetic
object is called an armature, and most armatures can be moved
with either direct current (DC) or alternating current (AC)
energizing the coil. The polarity of the magnetic field is irrelevant
for the purpose of attracting an iron armature. Solenoids can be
used to electrically open door latches, open or shut valves, move
robotic limbs, and even actuate electric switch mechanisms.
However, if a solenoid is used to actuate a set of switch contacts,
we have a device so useful it deserves its own name: the relay.

Relays are extremely useful when we have a need to control a large
amount of current and/or voltage with a small electrical signal. The
relay coil which produces the magnetic field may only consume
fractions of a watt of power, while the contacts closed or opened
by that magnetic field may be able to conduct hundreds of times
that amount of power to a load. In effect, a relay acts as a binary
(on or off) amplifier. Just as with transistors, the relay's ability to
control one electrical signal with another finds application in the
construction of logic functions. This topic will be covered in
greater detail in another lesson. For now, the relay's "amplifying"
ability will be explored.

ULN2003 I.C.:

  This i.c. function in our project as op amp through low voltage
convert into 12 volt amplification as used for easily operate heavy

                    voltage electrical relay and


The ULN2003 is a monolithic high voltage and high current
Darlington transistor arrays. It consists of seven NPN Darlington
pairs that feature high-voltage outputs with common-cathode
clamp diode for switching inductive loads. The collector-current
rating of a single Darlington pair is 500mA. The Darlington pairs
may be paralleled for higher current capability. Applications
include relay drivers, hammer drivers, lamp drivers, display drivers
(LED gas discharge), line drivers, and logic buffers. The ULN2003
has a 2.7kW series base resistor for each Darlington pair for
operation directly with TTL or 5V CMOS devices.

The ULN2003 is a very cost effective chip that acts like a switch.
The easiest way to explain its operation: It simply switches an
earth to/from an external circuit, and can withstand a continual
500mA current drain and a maximum 50V.

What's Inside?

The picture on the right is what the ULN2003 looks like internally.

Pins 1:7 are inputs, while pins 10:16 are high current sink drivers.
Between the I/Os is an independent Darlington pair (the
'Darlington pair' behaves like a single transistor with a high current
gain). When an input is driven high, the corresponding output will
basically become an earth. Alternately, when the input pin is low,
the output pin adopts high impedance. This allows external high-
current circuits to be driven by small micro-controllers. There are
seven channels ready to be used, and as mentioned earlier, the
ULN2003 can sink up-to 500mA between all the channels.


There is only one power connection, a common ground (Pin 8).
Here's an example of driving a high power LED with logic
voltages via the ULN2003 (note the LED is being driven by a 12
volt source, but controlled by the logic voltage);

For inductive loads, such as motors and relays, Pin 9 is connected
to the loads +V to shunt counter-electromotive force (EMF, also
known as CEMF) safely. That is, if the motor was connected to
+12V and then pin 16 of the ULN, then pin 9 would be connected
to the same +12V source as the motor. The ULN2003 has become
my primary choice to controlling external components - it’s cheap,
effective, and requires no operating voltages other than the
common ground. Keep in mind that you will have a voltage drop
of about 0.9v-1.0v over the UL2003 when in circuit.

            10k SIL Type Resistor Network

     This resistor is called a Single-In-Line (SIL) resistor network.

It is made with many resistors of the same value, all in one
package. One side of each resistor is connected with one side
of all the other resistors inside. One example of its use would
be to control the current in a circuit powering many light
emitting                    diodes                    (LEDs).
In the photograph on the left, 8 resistors are housed in the
package. Each of the leads on the package is one resistor. The
ninth lead on the left side is the common lead. The face value
of the resistance is printed. (It depends on the supplier. )
Some resistor networks have a "4S" printed on the top of the
resistor network. The 4S indicates that the package contains 4
independent resistors that are not wired together inside. The
housing has eight leads instead of nine. The internal wiring of
these typical resistor networks has been illustrated below.
The size (black part) of the resistor network which I have is
as follows: For the type with 9 leads, the thickness is 1.8 mm,
the height 5mm, and the width 23 mm. For the types with 8
component leads, the thickness is 1.8 mm, the height 5 mm,
and the width 20 mm.

The resistor's function is to reduce the flow of electric current.
This symbol             is used to indicate a resistor in a circuit diagram,
known                       as                 a                schematic.
Resistance value is designated in units called the "Ohm." A 1000
Ohm resistor is typically shown as 1K-Ohm (kilo Ohm), and 1000
K-Ohms is written as 1M-Ohm (megohm).

  Resistor color code

                                                Color    Value Multiplier

                                                Black      0       0            -

                                                Brown      1       1           ±1

                                                 Red       2       2           ±2

 Example 1                                      Orange     3       3          ±0.05
   10 x 103 = 10k ohm                           Yellow     4       4            -
   Tolerance(Gold) = ±5%                        Green      5       5          ±0.5

                                                 Blue      6       6          ±0.25

                                                Violet     7       7          ±0.1

                                                Gray       8       8            -

                                                White      9       9            -

                                                 Gold      -       -1          ±5

                                                Silver     -       -2         ±10
 Example 2
                                                None       -        -         ±20
   470 x 102 = 47k ohm
   Tolerance(Brown) = ±1%


A capacitor (formerly known as condenser) is a passive two-
terminal electrical component used to store energy in an electric

field. The forms of practical capacitors vary widely, but all contain
at      least        two electrical        conductors separated        by
a dielectric (insulator); for example, one common construction
consists of metal foils separated by a thin layer of insulating film.
Capacitors are widely used as parts of electrical circuits in many
common electrical devices.

When    there   is    a potential     difference (voltage)   across    the
conductors, a static electric field develops across the dielectric,
causing positive charge to collect on one plate and negative charge
on the other plate. Energy is stored in the electrostatic field. An
ideal   capacitor     is   characterized     by    a   single     constant
value, capacitance, measured in farads. This is the ratio of
the electric charge on each conductor to the potential difference
between them.

The capacitance is greatest when there is a narrow separation
between large areas of conductor; hence capacitor conductors are
often called "plates," referring to an early means of construction. In
practice, the dielectric between the plates passes a small amount
of leakage current and also has an electric field strength limit,
resulting in breakdown, while the conductors and leads introduce
an undesired inductance and resistance.

Capacitors are widely used in electronic circuits for blocking direct
current while   allowing alternating   current to   pass,   in   filter
networks, for smoothing the output of power supplies, in
the resonant circuits that tune radios to particular frequencies and
for many other purposes.


Below are your typical diode and its different representations. If
you’ve followed my diode research, you’ll know that I hate the
arrow version because according to how electrons flow, they go in
the opposite direction of the arrow.

Let’s look at the current and the direction the electrons travel.

In the above picture, if you have the negative terminal of the
battery matched up to the P-type portion of the diode, and therefore
the positive terminal of the battery matched up with the N-type
portion of the diode, there will be no current.

In this above picture the positive terminal of the battery is matched
with the P-type material of the diode, and likewise the negative
terminal of the battery is matched with the N-type material of the
diode. With this configuration, current can pass through.

Source of input supply
       12V Battery

  Step down transformer


This GSM modem is a highly flexible plug and play quad band
GSM modem for direct and easy Integration to RS232. Supports
features like Voice, Data/Fax, SMS, GPRS and integrated TCP/IP
· Insert SIM card: Press the yellow pin to remove the tray from
the SIM cardholder. After
Properly fixing the SIM card in the tray, insert the tray in the slot
· Connect Antenna: Screw the RF antenna on the RF cable output
· If voice call is needed, connect the Mic and speaker to stereo

·   Connect    RS232     Cable:    (Cable   provided   for   RS232
communication) Default baud rate is
9600 with 8-N-1, no hardware handshaking. Cable provided has
pins 7 and 8 shorted that will
Set to no hardware handshaking. In you need hardware
handshaking the pins 7-8 can be
Taken for signaling.
O Pin 2 is RS232 level TX out
O Pin 3 is RS232 level RX in
O Pin 5 is Ground
O Pin 7 RTS in (shorted to pin 8 in cable for no hardware
O Pin 8 CTS out (shorted to pin 7 in cable for no hardware
· Connect the power Supply (9-12V) to the power jack. Polarity
should be Center +ve and
Outer –ve DC jack.
· Network Led indicating various status of GSM module e.g.
Power on, network registration &
GPRS connectivity.
· After the Modem registers the network, led will blink in step of 3
seconds. At this stage you
Can start using Modem for your application.

· AT commands set section is covered in following document


ATE0 – Echo off
ATE1 – Echo on

ATD – call to dail a number
Syntax: ATD 9885622502;

ATDL – redail last teliphone number

ATA – answer an incomming call

ATH – Disconnect existing connection

AT+CMGD – to delete SMS
Syntax: AT+CMGD=1 -> deletes ‘1’ sms in sim card

AT+CMGR – to read SMS
Syntax: AT+CMGR=1 -> reads 1st sms in sim card

AT+CMGS – to send SMS
Syntax: AT+CMGS=9885622502 press enter
     Type text and press ctrl+z


+CREG: 2             // SIM UNREGISTERED

+CREG: 1,"4E2F","0067" // SIM REGISTERED

RING                      // CALL STATUS

+CLIP: "+919866166124",145,"",,"",0 // RECEIVED CALL
                             NUMBER FOR //EXAMPLE


+CLIP: "+919866166124", 145,"",”", 0


+CLIP: "+919866166124", 145,"",”", 0



Our project fully working and tested under our project guide and
external guide observation we all electrical parameters testing and
all fault was practically create and completely transformer protect
any damages and shut down. We thanks our all project helping
people colledge technical staff external guide and raw material
suppliers. We learn too much about transformer and its protection
from this project and I remember all time this academic year.


A handbook of transformer by V.k.mehta

Basic electronics and electrical j.p.prakashan jaipur


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