Unmanned Petrol Pump 2010

1. INTRODUCTION

In current days the petrol stations are operated manually. These petrol pumps are time

consuming and require more manpower. To place petrol stations in distant area it very costly to

provide excellent facility to the consumers all these problem are sorted

out by the use of unmanned power pump which requires less time to operate and it is effective

and can be installed anywhere the customer self going to avail the services the payment is done

by electronic clearing system. These petrol stations easily monitor with the video capturing and

alarming system over the time by a central control unit.

Today’s consumers are more mobile and more demanding than ever.

Consumers want more choices, more speed and more convenience. They’re less forgiving of

slow pumps and outdated features and searching for petrol station all over the

place. To upgrade market we need a dispenser that is reliable, user-friendly and ready to increase

our profitability. We need unmanned petrol station. Designed from the ground up, this

flexible, dependable and scalable fuel dispenser will meet our needs, today and tomorrow.

The world’s most consumer-friendly fuel dispenser.

The world’s most consumer-friendly fuel pump. It has the easy operated ATM machine. It had

easy operated graphics user interface (GUI). It is interface with high speed petrol dispenser

which is convenient for consumer to operate

Centralized control unit

As in today world men have no time to waste in this competitive world for the search of petrol.

Centralized control unit can easily access many number of unmanned petrol stations situated at

various locations. As by this technology we can reduce our expenditure, we can generate more

revenue from it.

Security from the outside

Unmanned petrol stations are growing in popularity largely to the fact that they provide petrol at

reduced prices. We understand that theft and fraud are a growing concern for today’s retailers.

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So we have applied our innovation toward developing dispensers that deter criminal activity

however not having a person keeping an eye on the customers or the station changes the security

requirements. The customers need to feel safe when filling up and any vandalism to the station

has to be quickly identified. We provide an all encompassing security system that can constantly

monitor multiple petrol stations from a central location, ensuring the

customers and stations well being at all times. Video surveillance of the station at all times

Customers are only a push button away if assistance is needed Pumps and pay terminals are

constantly monitored one central monitoring point for multiple stations

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1.1 OTHER APPLICATION

Automated teller machine

An automated teller machine (ATM) or automatic banking machine (ABM) is a

computerized telecommunications device that provides the clients of a financial institution with

access to financial transactions in a public space without the need for a cashier, human clerk or

bank teller. On most modern ATMs, the customer is identified by inserting a plastic ATM card

with a magnetic stripe or a plastic smart card with a chip, that contains a unique card number and

some security information such as an expiration date or CVVC (CVV). Authentication is

provided by the customer entering a personal identification number (PIN).

Using an ATM, customers can access their bank accounts in order to make cash withdrawals (or

credit card cash advances) and check their account balances as well as purchase cellphone

prepaid credit. If the currency being withdrawn from the ATM is different from that which the

bank account is denominated in (e.g.: Withdrawing Japanese Yen from a bank account

containing US Dollars), the money will be converted at a wholesale exchange rate. Thus, ATMs

often provide the best possible exchange rate for foreign traveler and are heavily used for this

purpose as well.

ATMs are known by various other names including Automated Transaction Machine, automated

banking machine, cash point (in Britain), money machine, bank machine, cash machine , hole-in-

the-wall, Bancomat (in various countries in Europe and Russia), Multibanco (after a registered

trade mark, in Portugal), and All Time Money in India.

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Hardware

FIG 1:ATM STRUCTURE

An ATM is typically made up of the following devices:

CPU (to control the user interface and transaction devices)

Magnetic and/or Chip card reader (to identify the customer)

PIN Pad (similar in layout to a Touch tone or Calculator keypad), often manufactured as

part of a secure enclosure.

Secure crypto-processor, generally within a secure enclosure.

Display (used by the customer for performing the transaction)

Function key buttons (usually close to the display) or a Touch screen (used to select the

various aspects of the transaction)

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Record Printer (to provide the customer with a record of their transaction)

Vault (to store the parts of the machinery requiring restricted access)

Housing (for aesthetics and to attach signage to)

Vending Machine

The Machine Accepts Money

When a customer approaches a machine and becomes interested in making a purchase, he must

first insert money to pay for his item. If the machine accepts paper money, the money is pulled in

using rollers. Once inside, the machine uses a digital scanner to identify the bill's denomination

before storing the bill away in a cash box. For coins, the machine identifies the value of the coin

using certain values specific to each coin. A quarter, for example, is identified by its diameter

of .955 inches, its thickness of 1.75 millimeters and its 119 ridges around its edge. A dime is

recognized by its diameter of .705 inches and its thickness of 1.35 millimeters. Other coins are

similarly recognized, making counterfeiting possible but exceptionally difficult.

The Customer Makes a Choice

Once sufficient money is inserted, the customer informs the machine of which product he would

like to purchase. In older vending machines, pulling or turning a knob activates a strictly

mechanical dispensing mechanism. In more modern machines, the customer enters a series of

letters and numbers corresponding to his selection before a basic processor electronically

activates a motor to dispense the merchandise. Finally, the machine compares the selection's

programmed price to the amount of money inserted; if the inserted funds total less than the price

of the item, the machine either simply refuses to dispense or sends an electronic message to a

display asking the customer to insert additional funds.

The Machine Dispenses the Product

Once the selection is made and has been paid for, the machine must dispense the product. While

some vintage machines used a strictly mechanical dispensing coil, most modern machines

electronically activate a motor which spins a spiraled merchandise dispenser. The metal coil is

shaped in a spiral with products inserted between each ridge. As a motor spins the coil, the

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rotation pushes products forward in much the same way as a screw pulls debris out of a hole. The

metal coils are sized very slightly longer than the shelf supporting the product, so when the

purchased item reaches the end of the shelf it simply falls (due to gravity) into a receiving bin at

the bottom of the machine. After the product falls, the customer simply retrieves the item from

the bin.

2. FUEL DISPENSER

A fuel dispenser is a machine at a filling station that is used to pump gasoline, diesel, CNG,

CGH2, HCNG, LPG, LH2, ethanol fuel, bio-fuels like biodiesel, kerosene, or other types of fuel

into vehicles. Fuel dispensers are also known as browsers (in Australia), petrol pumps (in

Commonwealth countries), or gas pumps (in North America).

2.1 History

The first gasoline pump was invented and sold by Sylvanus F. Bowser in Fort Wayne, Indiana on

September 5, 1885. This pump was not used for automobiles, as they had not been invented yet.

It was instead used for some kerosene lamps and stoves. He later improved upon the pump by

adding safety measures, and also by adding a hose to directly dispense fuel into automobiles. For

a while, the term bowser was used to refer to a vertical gasoline pump. Although the term is not

used anymore in the United States, it still is used sometimes in Australia and New Zealand.

Many early gasoline pumps had a calibrated glass cylinder on top. The desired quantity of fuel

was pumped up into the cylinder as indicated by the calibration. Then the pumping was stopped

and the gasoline was let out into the customers tank by gravity. When metering pumps came into

use, a small glass globe with a turbine inside replaced the measuring cylinder but assured the

customer that gasoline really was flowing into the tank.

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2.2 Design Implemented

A fuel dispenser is logically divided into two main parts — an electronic "head" containing an

embedded computer to control the action of the pump, drive the pump's displays, and

communicate to an indoor sales system; and secondly, the mechanical section which in a ‘self

contained’ unit has an electric motor, pumping unit, meters, pulsars and valves to physically

pump and control the fuel flow.

In some cases the actual pump may be sealed and immersed inside the fuel tanks on a site, in

which case it is known as a submersible pump. In general submersible solutions in Europe are

installed in hotter countries, where suction pumps may have problems overcoming cavitation

with warm fuels or when the distance from tank to pump is longer than a suction pump can

manage.

In modern pumps, the major variations are in the number of hoses or grades they can dispense,

the physical shape, and the addition of extra devices such as pay at the pump devices and

attendant "tag" readers.

Historically, fuel dispensers had a very wide range of designs to solve the mechanical problems

of mechanical pumping, reliable measurement, safety, and aesthetics. This has led to some

popularity in collecting antique dispensers.

Nozzles

Nozzles are attached to the pump via flexible hoses, allowing them to be placed into the vehicle's

filling inlet. The hoses are robust to survive hardships such as being driven over, and are often

attached using heavy spring or coil arrangements to provide additional strength.

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The nozzles are usually color coded to indicate which grade of fuel they dispense, however the

color coding differs between countries or even retailers. For example, a black handle in the UK

indicates that the fuel dispensed is diesel. In the US, diesel pumps commonly use green hoses

and green slipcovers over the nozzle.

Blending

In some countries, pumps are able to mix two grades of fuel together before dispensing; this is

referred to as blending or mixing. Typical usages are in a "mix" pump to add oil to petrol for

two-stroke motorcycles, to produce an intermediate octane rating from separate high and low

octane fuels, or to blend hydrogen and compressed natural gas (HCNG).

Flow measurement

One of the most important functions for the pump is to accurately measure the amount of fuel

pumped. Flow measurement is almost always done by a 4 stroke piston meter connected to an

electronic encoder. In older gas pumps, the meter is physically coupled to reeled meters (moving

wheels with numbers on the side), while newer pumps turn the meters movement into electrical

pulses using a rotary encoder.

The metrology of gasoline

Gasoline is difficult to sell in a fair and consistent manner by volumetric units. It expands and

contracts significantly as its temperature changes. A comparison of the coefficient of thermal

expansion for gasoline and water indicates that gasoline changes at about 4.5 times the rate of

water.

In the United States, the National Institute of Standards and Technology (NIST) specifies the

accuracy of the measurements in Handbook 44. Table 3.30 specifies the accuracy at 0.3%

meaning that a 10-US-gallon (37.9 L; 8.3 imp gal) purchase could vary between 9.97 US gal

(37.7 L; 8.3 imp gal) and 10.03 US gal (38.0 L; 8.4 imp gal) as to the actual amounts at the

delivery temperature of the gasoline.

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The reference temperature for gasoline volume measurement is 60 °F (16 °C). Ten gallons of

gasoline at that temperature expands to about 10.05 US gal (38.0 L; 8.4 imp gal) at 85 °F (29 °C)

and contracts to about 9.83 US gal (37.2 L; 8.2 imp gal) at 30 °F (−1 °C). Each of the three

volumes represents the same theoretical amount of energy. In one sense, ten gallons of gasoline

purchased at 30° F is about 3.2% more potential energy than ten gallons purchased at 85° F.

Most gasoline is stored in tanks underneath the filling station. Modern tanks are non-metallic and

sealed to stop leaks. Some have double walls or other structures that provide inadvertent thermal

insulation while pursuing the main goal of keeping gasoline out of the soil around the tank. The

net result is that while the air temperature can easily vary between 30° F and 85° F, the gasoline

in the insulated tank changes temperature much more slowly.

Temperature compensation is common at the wholesale transaction level in the United States and

most other countries. At the retail consumer level, Canada has converted to automatic

temperature compensation and the United States has not. Where automatic temperature

compensation is used, it can add up to 0.2% of uncertainty for mechanical-based compensation

and 0.1% for electronic compensation.

There are many fewer retail outlets for gasoline in the United States today than there were in

1980. Larger outlets sell gasoline rapidly, as much as 30,000 US gal (113,562 L; 24,980 imp gal)

in a single day, even in remote places. Most finished product gasoline is delivered in 8 to 16

thousand gallon tank trucks so two deliveries in a 24 hour period is common. The belief is that

the gasoline spends so little time in the retail sales system that its temperature at the point of sale

does not vary significantly from winter to summer or by region. Canada has lower overall

population densities and geographically larger gasoline distribution systems, compared to the

United States. Temperature compensation at the retail level improves the fairness under those

conditions.

Higher energy prices have raised awareness of this issue for consumers. At the same time,

alternative fuel applications are now reaching the retail market and accurate comparisons

between them in normal usage are needed. Eventually the basis for retail sales will change from

volume units in liters or gallons to energy units such as the BTU, joule, therm, or kWh so that

electricity, liquids, liquefied gases and compressed gases can all be sold and taxed uniformly.

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In some regions, regular required inspections are conducted to insure the accuracy of fuel

dispensers. For example, in the US state of Florida, the Florida Department of Agriculture and

Consumer Services conducts regular tests of calibration and fuel quality at individual dispensers.

The department also conducts random undercover inspections using specially designed vehicles

that can check the accuracy of the dispensers. The department issues correction required notices

to stations with pumps found to be inaccurate.[4] Most other US states conduct similar

inspections.

Communications components

The technology for communicating with gas pumps from a point of sale or other controller varies

widely, involving a variety of hardware (RS-485, RS-422, current loop, and others) and

proprietary software protocols. Traditionally these variations gave pump manufacturers a natural

tie-in for their own point-of-sale systems, since only they understood the protocols. [5]

An effort to standardize this in the 1990s resulted in the International Forecourt Standards

Forum, which has had considerable success in Europe, but has less presence elsewhere.

("Forecourt" refers to the land area on which the fuel dispensers are located.)

Automatic cut-off in fuel dispenser

The shut-off valve was invented in Olean, New York in 1939 by Richard C. Corson. At a loading

dock at the Socony Vacuum Oil Company, Corson observed a worker filling a barrel with

gasoline and thought it inefficient. The sound of a toilet flushing later gave him the idea for a

"butterfly float." After developing a prototype with his assistant, Paul Wenke, Corson gave the

suggestion to the company who later filed for a patent in his name. The initial intent of the

device was to "allow a person to fill more than one barrel [of gasoline] at the same time." This

mechanism eventually developed into the modern gasoline pump cut-off valve.

Most modern pumps have an auto cut-off feature that stops the flow when the tank is full. This is

done with a second tube, the sensing tube, that runs from just inside the mouth of the nozzle up

to a Venturi pump in the pump handle. While the tank is being filled, air displaced from the tank

is drawn up this tube. Once the fuel level reaches the mouth of the sensing tube, air is no longer

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drawn up the sensing line. A mechanical valve in the pump handle detects this change of

pressure and closes, preventing the flow of fuel.

Other components

A modern fuel pump will often contain control equipment for the vapor recovery system, which

prevents gasoline vapor from escaping to the air. in the UK for example any new forecourt with a

predicted throughput in excess of 500 M3 per month is required to have active vapour recovery

installed.

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3. BASIC DESCRIPTION

AN OVERVIEW DIAGRAM: UNMANNED PETROL PUMP

FIG 2: UNMANNED PETROL PUMP

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DESKTOP COMPUTER

WITH

NETWORK INTERFACE

MICROCONTROLLER

FUEL DISPINSER

BANKCUSTOMER IN-

REQUEST FOR FUEL

CUSTOMER OUT-

OUTSIDE CONTROL UNIT

Unmanned Petrol Pump 2010

3.1 GENERAL DESCRIPTION

The unmanned petrol pump is a system in which we have defined the co-relation of fuel dispenser

presently used to the new adaptive electronic component. So, we tried to make the system more

efficient at a low cost of manufacturing. We had a system in which we added the feature of

microcontroller and other electronic devices to sense the need of fuel and also make the gateway

to the payment mode from the outside sources (such as from banks, local prepaid account, etc.).

As a person come into this system he/she enter his/her requirement of need of the fuel on the

desktop computer. The command entered into the desktop computer, the computer send the

command to the control unit that a person want to access the system and require specific amount

of fuel ,then the server at control unit check that petrol pump could be able to fulfill the

requirement of the customer. It is done by checking the level of fuel in the fuel dispenser. If the

fuel dispenser is not able to fulfill the requirement of the customer then the server tell to the

customer that it requirement could not be fulfill your requirement.

If the requirement of the customer could be fulfilled then server asks to the customer to select the

payment mode he/she want to select, if the plastic money payment mode is selected. Then server

asks to swap its card then the payment of customer is debited through the customer’s account.

Once the payment is made then the server commands the fuel dispenser to fulfill the requirement

of the customer by providing fuel to the customer.

The command received by the desktop computer through network interface then it pass the

command to the microcontroller through serial port connection. The command received by the

microcontroller. It manipulate for how much time a motor is to be run to fulfill the requirement

of the customer. This process in done by the internal program stored in the microcontroller.

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4. ACTIVE AND PASSIVE ELEMENTS

4.1. PASSIVE ELEMENTS

CAPACITORS:

A capacitor or condenser is a passive electronic component

consisting of a pair of conductors separated by a

dielectric (insulator). When a potential difference (voltage)

exists across the conductors, an electric field is present in

the dielectric. This field stores energy and produces a

mechanical force between the conductors. The effect is greatest when there is a narrow

separation between large areas of conductor hence capacitor conductors are often called plates.

An ideal capacitor is characterized by a single constant value, capacitance, which is measured in

farads. This is the ratio of the electric charge on each conductor to the potential difference

between them. In practice, the dielectric between the plates passes a small amount of leakage

current. The conductors and leads introduce an equivalent series resistance and the dielectric has

an electric field strength limit resulting in a breakdown voltage.

Capacitors are widely used in electronic circuits to block the flow of direct current while

allowing alternating current to pass, to filter out interference, to smooth the output of power

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FIG 3:A typical electrolytic capacitor

Unmanned Petrol Pump 2010

supplies, and for many other purposes. They are used in resonant circuits in radio frequency

equipment to select particular frequencies from a signal with many frequencies.

THEORY OF OPERATION

Charge separation in a parallel-plate capacitor causes

an internal electric field. A dielectric (orange) reduces the

field and increases the capacitance. A simple demon-

stration of a parallel-plate capacitor. A capacitor consists of

two conductors separated by a non-conductive region. The

non-conductive substance is called the dielectric medium,

although this may also mean a vacuum or a semiconductor depletion region chemically identical

to the conductors. A capacitor is assumed to be self-contained and isolated, with no net electric

charge and no influence from an external electric field. The conductors thus contain equal and

opposite charges on their facing surfaces and the dielectric contains an electric field. The

capacitor is a reasonably general model for electric fields within electric circuits.

An ideal capacitor is wholly characterized by a constant capacitance C, defined as the ratio of

charge ±Q on each conductor to the voltage V between them:

Sometimes charge buildup affects the mechanics of the capacitor, causing the capacitance to

vary. In this case, capacitance is defined in terms of incremental changes:

In SI units, a capacitance of one farad means that one coulomb of charge on each conductor

causes a voltage of one volt across the device.

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FIG 4 :OPERATION

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PARALLEL PLATE MODEL

Dielectric is placed between two conducting plates, each of

area A and with a separation of d .The simplest capacitor

consists of two parallel conductive plates separated by a

dielectric with permittivity ε (such as air). The model may

also be used to make qualitative predictions for other

device geometries. The plates are considered to extend uniformly over an area A and a charge

density ±ρ = ±Q/A exists on their surface. Assuming that the width of the plates is much greater

than their separation d, the electric field near the centre of the device will be uniform with the

magnitude E = ρ/ε. The voltage is defined as the line integral of the electric field between the

plates

Solving this for C = Q/V reveals that capacitance increases with area and decreases with

separation

.

The capacitance is therefore greatest in devices made from materials with a high permittivity.

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FIG5: CAPACITOR

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NETWORKS

Series and parallel circuits

For capacitors in parallel

For capacitors in series

TYPES OF CAPACITOR

Practical capacitors are available commercially in many different forms. The type of internal

dielectric, the structure of the plates and the device packaging all strongly affect the

characteristics of the capacitor, and its applications.

Values available range from very low (pico-farad range; while arbitrarily low values are in

principle possible, stray (parasitic) capacitance in any circuit is the limiting factor) to about 5  kF

super capacitors. Several solid dielectrics are available, including paper, plastic, glass, mica and

ceramic materials. Paper was used extensively in older devices and offers relatively high voltage

performance. However, it is susceptible to water absorption, and has been largely replaced by

plastic film capacitors. Plastics offer better stability and aging performance, which makes them

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FIG 6:PARALLEL N/W

FIG 7: SERIES N/W

Unmanned Petrol Pump 2010

useful in timer circuits, although they may be limited to low operating temperatures and

frequencies.

Ceramic capacitors

Ceramic capacitors are generally small, cheap and useful for high frequency applications

although their capacitance varies strongly with voltage and they age poorly.

Electrolytic Capacitors

Electrolytic capacitors and super-capacitors are used to store small and larger amounts of energy,

respectively, ceramic capacitors are often used in resonators, and parasitic capacitance occurs in

circuits wherever the simple conductor-insulator-conductor structure is formed unintentionally

by the configuration of the circuit layout.

Electrolytic capacitors use an aluminum or tantalum plate with an oxide dielectric layer. The

second electrode is a liquid electrolyte, connected to the circuit by another foil plate. Electrolytic

capacitors offer very high capacitance but suffer from poor tolerances, high instability, gradual

loss of capacitance especially when subjected to heat, and high leakage current. The conductivity

of the electrolyte drops at low temperatures, which increases equivalent series resistance. While

widely used for power-supply conditioning, poor high-frequency characteristics make them

unsuitable for many applications. Tantalum capacitors offer better frequency and temperature

characteristics than aluminum, but higher dielectric absorption and leakage.

Super Capacitors

Super-capacitors store large amounts of energy. Super-capacitors made from carbon aerogel,

carbon nanotubes, or highly porous electrode materials offer extremely high capacitance (up to 5

kF as of 2010) and can be used in some applications instead of rechargeable batteries.

Alternating current capacitors are specifically designed to work on line (mains) voltage AC

power circuits.

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Capacitors have many uses in electronic and electrical systems. They are so common that it

is a rare electrical product that does not include at least one for some purpose.

APPLICATIONS

Energy storage

Power factor correction

Signal coupling

Decoupling

Noise filters

Motor starters

Signal processing

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/RESISTORS

A resistor is a two-terminal electronic component that produces a voltage across its terminals

that is proportional to the electric current passing through it in accordance with Ohm's law:

V = IR

Resistors are elements of electrical networks and electronic circuits and are ubiquitous in most

electronic equipment. Practical resistors can be made of various compounds and films, as well as

resistance wire (wire made of a high-resistivity alloy, such as nickel/chrome).

The primary characteristics of a resistor are the resistance, the tolerance, maximum working

voltage and the power rating. Other characteristics include temperature coefficient, noise, and

inductance. Less well-known is critical resistance, the value below which power dissipation

limits the maximum permitted current flow, and above which the limit is applied voltage. Critical

resistance is determined by the design, materials and dimensions of the resistor.

Resistors can be integrated into hybrid and printed circuits, as well as integrated circuits. Size,

and position of leads (or terminals) are relevant to equipment designers; resistors must be

physically large enough not to overheat when dissipating their power.

THEORY OF OPERATON

(a) Ohm's law

The behavior of an ideal resistor is dictated by the relationship specified in Ohm's law:

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Ohm's law states that the voltage (V) across a resistor is proportional to the current (I) through it

where the constant of proportionality is the resistance (R).

SERIES AND PARALLEL RESISTORS

Resistors in a parallel configuration

The current through resistors in series stays the same, but the voltage across each resistor can be

different. The sum of the potential differences (voltage) is equal to the total voltage. To find their

total resistance:

Resistors in series configuration

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RESISTOR MARKING

Most axial resistors use a pattern of colored stripes to indicate resistance. Surface-mount resistors

are marked numerically, if they are big enough to permit marking; more-recent small sizes are

impractical to mark. Cases are usually tan, brown, blue, or green, though other colors are

occasionally found such as dark red or dark gray.

Early 20th century resistors, essentially uninsulated, were dipped in paint to cover their entire

body for color coding. A second color of paint was applied to one end of the element, and a color

dot (or band) in the middle provided the third digit. The rule was "body, tip, dot", providing two

significant digits for value and the decimal multiplier, in that sequence. Default tolerance was

±20%. Closer-tolerance resistors had silver (±10%) or gold-colored (±5%) paint on the other end.

Four-band resistors

Four-band identification is the most commonly used color-coding scheme on resistors. It consists

of four colored bands that are painted around the body of the resistor. The first two bands encode

the first two significant digits of the resistance value, the third is a power-of-ten multiplier or

number-of-zeroes, and the fourth is the tolerance accuracy, or acceptable error, of the value. The

first three bands are equally spaced along the resistor; the spacing to the fourth band is wider.

Sometimes a fifth band identifies the thermal coefficient, but this must be distinguished from the

true 5-color system, with 3 significant digits.

For example, green-blue-yellow-red is 56×104 Ω = 560 kΩ ± 2%. An easier description can be as

followed: the first band, green, has a value of 5 and the second band, blue, has a value of 6, and

is counted as 56. The third band, yellow, has a value of 104, which adds four 0's to the end,

creating 560,000 Ω at ±2% tolerance accuracy. 560,000 Ω changes to 560 kΩ ±2% (as a kilo- is

103)

Table at next page:

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Color 1st band 2nd band 3rd band (multiplier) 4th band (tolerance) Temp. Coefficient

Black 0 0 ×100

Brown 1 1 ×101 ±1% (F) 100 ppm

Red 2 2 ×102 ±2% (G) 50 ppm

Orange 3 3 ×103 15 ppm

Yellow 4 4 ×104 25 ppm

Green 5 5 ×105 ±0.5% (D)

Blue 6 6 ×106 ±0.25% (C)

Violet 7 7 ×107 ±0.1% (B)

Gray 8 8 ×108 ±0.05% (A)

White 9 9 ×109

Gold ×10−1 ±5% (J)

Silver ×10−2 ±10% (K)

None ±20% (M)

FIG 8:RESISTOR TABLE

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5-band axial resistors

5-band identification is used for higher precision (lower tolerance) resistors (1%, 0.5%, 0.25%,

0.1%), to specify a third significant digit. The first three bands represent the significant digits,

the fourth is the multiplier, and the fifth is the tolerance. Five-band resistors with a gold or silver

4th band are sometimes encountered, generally on older or specialized resistors. The 4th band is

the tolerance and the 5th the temperature coefficient.

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INDUCTOR

An inductor or a reactor is a passive electrical component that can store energy in a magnetic

field created by the electric current passing through it. An inductor's ability to store magnetic

energy is measured by its inductance, in units of henries. Typically an inductor is a conducting

wire shaped as a coil, the loops helping to create a strong magnetic field inside the coil due

toFaraday's Law of Induction. Inductors are one of the basic electronic components used in

electronics where current and voltage change with time, due to the ability of inductors to delay

and reshape alternating currents. In everyday speak inductors are sometimes called chokes, but

this refers to only a particular type and purpose of inductor.

Inductance (L) (measured in henries) is an effect resulting from the magnetic field that forms

around a current-carrying conductor which tends to resist changes in the current. Electric

current through the conductor creates a magnetic flux proportional to the current, and a change in

this current creates a corresponding change in magnetic flux which, in turn, by Faraday's

Law generates an electromotive force (EMF) that opposes this change in current. Inductance is a

measure of the amount of EMF generated per unit change in current. For example, an inductor

with an inductance of 1 henry produces an EMF of 1 volt when the current through the inductor

changes at the rate of 1 ampere per second. The number of loops, the size of each loop, and the

material it is wrapped around all affect the inductance. For example, the magnetic flux linking

these turns can be increased by coiling the conductor around a material with a

high permeability such as iron. This can increase the inductance by 2000 times, although less so

at high frequencies.

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INTERNAL DIAGRAM OF UNMANNED PETROL PUMP

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FIG9: INTERNAL DIAGRAM OF UNMANNED PETROL PUMP

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5. MICROCONTROLLER

A microcontroller is a small computer on a single integrated circuit containing a processor core,

memory, and programmable input/output peripherals. Program memory in the form of NOR

flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM.

Microcontrollers are designed for embedded applications, in contrast to the microprocessorsused

in personal computers or other general purpose applications.

Microcontrollers are used in automatically controlled products and devices, such as automobile

engine control systems, implantable medical devices, remote controls, office machines,

appliances, power tools, and toys. By reducing the size and cost compared to a design that uses a

separate microprocessor, memory, and input/output devices, microcontrollers make it

economical to digitally control even more devices and processes. Mixed signal microcontrollers

are common, integrating analog components needed to control non-digital electronic systems.

Some microcontrollers may use four-bit words and operate at clock rate frequencies as low as

4 kHz, for low power consumption (milliwatts or microwatts). They will generally have the

ability to retain functionality while waiting for an event such as a button press or other interrupt;

power consumption while sleeping (CPU clock and most peripherals off) may be just nanowatts,

making many of them well suited for long lasting battery applications. Other microcontrollers

may serve performance-critical roles, where they may need to act more like a digital signal

processor (DSP), with higher clock speeds and power consumption.

A microcontroller can be considered a self-contained system with a processor, memory and

peripherals and can be used as an embedded system. The majority of microcontrollers in use

today are embedded in other machinery, such as automobiles, telephones, appliances, and

peripherals for computer systems. These are called embedded systems. While some embedded

systems are very sophisticated, many have minimal requirements for memory and program

length, with no operating system, and low software complexity. Typical input and output devices

include switches, relays, solenoids, LEDs, small or custom LCD displays, radio frequency

devices, and sensors for data such as temperature, humidity, light level etc.

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Interrupts

Microcontrollers must provide real time (predictable, though not necessarily fast) response to

events in the embedded system they are controlling. When certain events occur,

an interrupt system can signal the processor to suspend processing the current instruction

sequence and to begin an interrupt service routine (ISR, or "interrupt handler"). The ISR will

perform any processing required based on the source of the interrupt before returning to the

original instruction sequence. Possible interrupt sources are device dependent, and often include

events such as an internal timer overflow, completing an analog to digital conversion, a logic

level change on an input such as from a button being pressed, and data received on a

communication link. Where power consumption is important as in battery operated devices,

interrupts may also wake a microcontroller from a low power sleep state where the processor is

halted until required to do something by a peripheral event.

Programs

Microcontroller programs must fit in the available on-chip program memory, since it would be

costly to provide a system with external, expandable, memory. Compilers and assemblers are

used to turn high-level language and assembler language codes into a compact machine code for

storage in the microcontroller's memory. Depending on the device, the program memory may be

permanent, read-only memory that can only be programmed at the factory, or program memory

may be field-alterable flash or erasable read-only memory.

Other microcontroller features

Microcontrollers usually contain from several to dozens of general purpose input/output pins

(GPIO). GPIO pins are software configurable to either an input or an output state. When GPIO

pins are configured to an input state, they are often used to read sensors or external signals.

Configured to the output state, GPIO pins can drive external devices such as LED's or motors.

Many embedded systems need to read sensors that produce analog signals. This is the purpose of

the analog-to-digital converter (ADC). Since processors are built to interpret and process digital

data, i.e. 1s and 0s, they won't be able to do anything with the analog signals that may be sent to

it by a device. So the analog to digital converter is used to convert the incoming data into a form

that the processor can recognize. A less common feature on some microcontrollers is a digital-to-

analog converter (DAC) that allows the processor to output analog signals or voltage levels.

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In addition to the converters, many embedded microprocessors include a variety of timers as

well. One of the most common types of timers is the Programmable Interval Timer (PIT). A PIT

just counts down from some value to zero. Once it reaches zero, it sends an interrupt to the

processor indicating that it has finished counting. This is useful for devices such as thermostats,

which periodically test the temperature around them to see if they need to turn the air conditioner

on, the heater on, etc. Time Processing Unit (TPU) is a sophisticated timer. In addition to

counting down, the TPU can detect input events, generate output events, and perform other

useful operations. A dedicated Pulse Width Modulation (PWM) block makes it possible for the

CPU to control power converters, resistive loads, motors, etc., without using lots of CPU

resources in tight timer loops. Universal Asynchronous Receiver/Transmitter (UART) block

makes it possible to receive and transmit data over a serial line with very little load on the CPU.

Dedicated on-chip hardware also often includes capabilities to communicate with other devices

(chips) in digital formats such as I2C and Serial Peripheral Interface (SPI).

High Integration

In contrast to general-purpose CPUs, micro-controllers may not implement an external address

or data bus as they integrate RAM and non-volatile memory on the same chip as the CPU. Using

fewer pins, the chip can be placed in a much smaller, cheaper package.

A micro-controller is a single integrated circuit, commonly with the following features:

central processing unit  - ranging from small and simple 4-bit processors to complex

32- or 64-bit processors

discrete input and output bits, allowing control or detection of the logic state of an

individual package pin

serial input/output such as serial ports (UARTs)

peripherals  such as timers, event counters, PWM generators, and watchdog

volatile memory (RAM) for data storage

ROM , EPROM, EEPROM or Flash memory for program and operating parameter

storage

clock generator  - often an oscillator for a quartz timing crystal, resonator or RC

circuit

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many include analog-to-digital converters

in-circuit programming and debugging support

This integration drastically reduces the number of chips and the amount of wiring and circuit

board space that would be needed to produce equivalent systems using separate chips.

Microcontroller architectures vary widely. Some designs include general-purpose

microprocessor cores, with one or more ROM, RAM, or I/O functions integrated onto the

package. Other designs are purpose built for control applications. A micro-controller instruction

set usually has many instructions intended for bit-wise operations to make control programs

more compact. For example, a general purpose processor might require several instructions to

test a bit in a register and branch if the bit is set, where a micro-controller could have a single

instruction to provide that commonly-required function.

Microcontrollers typically do not have a math coprocessor, so floating point arithmetic is

performed by software.

Programming environments

Microcontrollers were originally programmed only in assembly language, but various high-level

programming languages are now also in common use to target microcontrollers. These languages

are either designed specially for the purpose, or versions of general purpose languages such as

the C programming language. Compilers for general purpose languages will typically have some

restrictions as well as enhancements to better support the unique characteristics of

microcontrollers. Some microcontrollers have environments to aid developing certain types of

applications. Microcontroller vendors often make tools freely available to make it easier to adopt

their hardware.

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5.1. MICROCONTROLLER (PIC16F72)

DEVICE OVERVIEW

The PIC16F72 belongs to the Mid-Range family of the PICmicro devices. A block diagram of

the device is shown in Figure. The program memory contains 2K words, which translate to 2048

instructions, since each 14-bit program memory word is the same width as each device

instruction. The data memory (RAM) contains 128 bytes.

There are 22 I/O pins that are user configurable on a pin-to-pin basis. Some pins are multiplexed

with other device functions. These functions include:

External interrupt

Change on PORTB interrupt

Timer0 clock input

Timer1 clock/oscillator

Capture/Compare/PWM

A/D converter

SPI/I2C

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FIG 10: MICROCONTROLLER:PIC 16F72

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High Performance RISC CPU

Only 35 single word instructions to learn

All single cycle instructions except for program branches, which are two-cycle

Operating speed: DC - 20 MHz clock input DC - 200 ns instruction cycle

2K x 14 words of Program Memory, 128 x 8 bytes of Data Memory (RAM)

Pin-out compatible to PIC16C72/72A and PIC16F872

Interrupt capability

Eight-level deep hardware stack

Direct, Indirect and Relative Addressing modes.

Peripheral Features

High Sink/Source Current: 25 mA

Timer0: 8-bit timer/counter with 8-bit prescaler

Timer1: 16-bit timer/counter with prescaler, can be incremented during SLEEP via

external crystal/clock

Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler

Capture, Compare, PWM (CCP) module

Capture is 16-bit, max. resolution is 12.5 ns

Compare is 16-bit, max. resolution is 200 ns

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PWM max. resolution is 10-bit

8-bit, 5-channel analog-to-digital converter

Synchronous Serial Port (SSP) with SPI™ (Master/Slave) and I2C™ (Slave)

Brown-out detection circuitry for Brown-out Reset (BOR)

CMOS Technology

Low power, high speed CMOS FLASH technology

Fully static design

Wide operating voltage range: 2.0V to 5.5V

Industrial temperature range

Low power consumption:

< 0.6 mA typical @ 3V, 4 MHz

20 μA typical @ 3V, 32 kHz

< 1 μA typical standby current

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FIG 11:PIN DIAGRAM

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FIG 12:PIN DESCRIPTION TABLE

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MEMORY ORGANIZATION

There are two memory blocks in the PIC16F72 device. These are the program memory and the

data memory. Each block has separate buses so that concurrent access can occur. Program

memory and data memory are explained in this section. Program memory can be read internally

by the user code. The data memory can further be broken down into the general purpose RAM

and the Special Function Registers (SFRs). The operation of the SFRs that control the “core” are

described here. The SFRs used to control the peripheral modules are described in the section

discussing each individual peripheral module.

Additional information on device memory may be found in the PICmicro Mid-Range.

Program Memory Organization

PIC16F72 devices have a 13-bit program counter capable of addressing a 8K x 14 program

memory space. The address range for this program memory is 0000h - 07FFh. Accessing a

location above the physically implemented address will cause a wraparound.

The RESET Vector is at 0000h and the Interrupt Vector is at 0004h.

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Data Memory Organization

The Data Memory is partitioned into multiple banks that contain the General Purpose Registers

and the Special Function Registers. Bits RP1 (STATUS<6>) and RP0

(STATUS<5>) are the bank select bits.

Each bank extends up to 7Fh (128 bytes). The lower locations of each bank are reserved for the

Special Function Registers. Above the Special Function Registers are General Purpose Registers,

implemented as static RAM. All implemented banks contain SFRs. Some “high use” SFRs from

one bank may be mirrored in another bank, for code reduction and quicker access (e.g., the

STATUS register is in Banks 0 - 3).

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6. SOME ESSENTIAL COMPONENT USED

6.1. TRANSFORMER

A transformer is a device that transfers electrical energy

 from one circuit to another through inductively coupled

 conductors—the transformer's coils. A varying current

 in the first or primary winding creates a varying ma-

gnetic flux in the transformer's core, and thus

a varying magnetic field through the secondary wi-

nding. This varying magnetic field induces a varying 

electromotive force (EMF) or "voltage" in the second-

dary winding. This effect is called mutual induction.

If a load is connected to the secondary, an electric current will flow in the secondary winding and

electrical energy will be transferred from the primary circuit through the transformer to the load.

In an ideal transformer, the induced voltage in the secondary winding (VS) is in proportion to the

primary voltage (VP), and is given by the ratio of the number of turns in the secondary (NS) to the

number of turns in the primary (NP) as follows:

By appropriate selection of the ratio of turns, a transformer thus allows an alternating current

(AC)voltage to be "stepped up" by making NS greater than NP, or "stepped down" by

making NS less than NP.

In the vast majority of transformers, the windings are coils wound around a ferromagnetic

core, air-core transformers being a notable exception.

Transformers range in size from a thumbnail-sized coupling transformer hidden inside a stage

microphone to huge units weighing hundreds of tons used to interconnect portions of power

grids. All operate with the same basic principles, although the range of designs is wide. While

new technologies have eliminated the need for transformers in some electronic circuits,

transformers are still found in nearly all electronic devices designed for household ("mains")

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FIG 13: TRANSFORMER

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voltage. Transformers are essential for high voltage power transmission, which makes long

distance transmission economically practical.

The transformer is based on two principles: firstly, that an electric current can produce

a magnetic field (electromagnetism) and secondly that a changing magnetic field within a coil of

wire induces a voltage across the ends of the coil (electromagnetic induction). Changing the

current in the primary coil changes the magnetic flux that is developed. The changing magnetic

flux induces a voltage in the secondary coil.

An ideal transformer is shown in the adjacent figure. Current passing through the primary coil

creates a magnetic field. The primary and secondary coils are wrapped around a core of very

high magnetic permeability, such as iron, so that most of the magnetic flux passes through both

the primary and secondary coils.

Induction law

The voltage induced across the secondary coil may be calculated fromFaraday's law of induction,

which states that:

where VS is the instantaneous voltage, NS is the number of turns in the secondary coil

and Φ equals the magnetic flux through one turn of the coil. If the turns of the coil are oriented

perpendicular to the magnetic field lines, the flux is the product of the magnetic flux

density B and the area A through which it cuts. The area is constant, being equal to the cross-

sectional area of the transformer core, whereas the magnetic field varies with time according to

the excitation of the primary. Since the same magnetic flux passes through both the primary and

secondary coils in an ideal transformer, the instantaneous voltage across the primary winding

equals

Taking the ratio of the two equations for VS and VP gives the basic equation for stepping up or

stepping down the voltage

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6.2 Voltage regulator-7805

A voltage regulator is an electrical regulator designed

to automatically maintain a constant voltage level.

It may use an electromechanical mechanism, or passive

or active electronic components. Depending on the design,

it may be used to regulate one or more AC or DC voltages.

With the exception of passive shunt regulators, all modern electronic voltage regulators operate

by comparing the actual output voltage to some internal fixed reference voltage. Any difference

is amplified and used to control the regulation element in such a way as to reduce the voltage

error. This forms a negative feedback control loop; increasing the open-loop gain tends to

increase regulation accuracy but reduce stability (avoidance of oscillation, or ringing during step

changes). There will also be a trade-off between stability and the speed of the response to

changes. If the output voltage is too low (perhaps due to input voltage reducing or load current

increasing), the regulation element is commanded, up to a point, to produce a higher output

voltage - by dropping less of the input voltage (for linear series regulators and buck switching

regulators), or to draw input current for longer periods (boost-type switching regulators); if the

output voltage is too high, the regulation element will normally be commanded to produce a

lower voltage. However, many regulators have over-current protection, so that they will entirely

stop sourcing current (or limit the current in some way) if the output current is too high, and

some regulators may also shut down if the input voltage is outside a given range

PIN Diagram

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FIG14: VOLTAGE REGULATOR

FIG15: VOLTAGE REGULATOR-7805

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6.3. MAX232

The MAX232 is an integrated circuit that converts sig-

nals from an RS-232 serial port to signals suitable f-

or use in TTL compatible digital logic circuits. The

MAX232 is a dual driver/receiver and typically conv-

erts the RX, TX, CTS and RTS signals.

The drivers provide RS-232 voltage level outputs (ap-

prox. ± 7.5 V) from a single + 5 V supply via on-

chip charge pumps and external capacitors. This makes it useful for implementing RS-232 in

devices that otherwise do not need any voltages outside the 0 V to + 5 V range, as power

supply design does not need to be made more complicated just for driving the RS-232 in this

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

5 V TTL levels. These receivers have a typical threshold of 1.3 V, and a typical hysteresis of

0.5 V. The later MAX232A is backwards compatible with the original MAX232 but may operate

at higher baud rates and can use smaller external capacitors – 0.1 μF in place of the 1.0 μF

capacitors used with the original device.

The newer MAX3232 is also backwards compatible, but operates at a broader voltage range,

from 3 to 5.5V.

Voltage levels

It is helpful to understand what occurs to the voltage levels. When a MAX232 IC receives a TTL

level to convert, it changes a TTL Logic 0 to between +3 and +15V, and changes TTL Logic 1 to

between -3 to -15V, and vice versa for converting from RS232 to TTL. This can be confusing

when you realize that the RS232 Data Transmission voltages at a certain logic state are opposite

from the RS232 Control Line voltages at the same logic state. To clarify the matter, see the table

below. For more information see RS-232 Voltage Levels.

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FIG 16: MAX 232 Interface

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RS-232-PROTOCOL

In communications, RS-232 (Recommended Standard 232) is a standard for serial binary single-

ended data and control signals connecting between a DTE (Data Terminal Equipment) and a

DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports. A

similar ITU-T standard is V.24.

Section I.02 Scope of the standard

The Electronics Industries Association (EIA) standard RS-232-C[1] as of 1969 defines:

Electrical signal characteristics such as voltage levels, signaling rate, timing and slew-

rate of signals, voltage withstand level, short-circuit behavior, and maximum load

capacitance.

Interface mechanical characteristics, pluggable connectors and pin identification.

Functions of each circuit in the interface connector.

Standard subsets of interface circuits for selected telecom applications.

The standard does not define such elements as

character encoding (for example, ASCII, Baudot code or EBCDIC)

the framing of characters in the data stream (bits per character, start/stop bits, parity)

protocols for error detection or algorithms for data compression

bit rates for transmission, although the standard says it is intended for bit rates lower than

20,000 bits per second. Many modern devices support speeds of 115,200 bit/s and above

power supply to external devices.

Details of character format and transmission bit rate are controlled by the serial port hardware,

often a single integrated circuit called a UART that converts data from parallel to asynchronous

start-stop serial form. Details of voltage levels, slew rate, and short-circuit behavior are typically

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controlled by a line-driver that converts from the UART's logic levels to RS-232 compatible

signal levels, and a receiver that converts from RS-232 compatible signal levels to the UART's

logic levels.

Limitations of the standard

Because the application of RS-232 has extended far beyond the original purpose of

interconnecting a terminal with a modem, successor standards have been developed to address

the limitations. Issues with the RS-232 standard include:

The large voltage swings and requirement for positive and negative supplies increases

power consumption of the interface and complicates power supply design. The voltage

swing requirement also limits the upper speed of a compatible interface.

Single-ended signaling referred to a common signal ground limits the noise immunity and

transmission distance.

Multi-drop connection among more than two devices is not defined. While multi-drop

"work-arounds" have been devised, they have limitations in speed and compatibility.

Asymmetrical definitions of the two ends of the link make the assignment of the role of a

newly developed device problematic; the designer must decide on either a DTE-like or

DCE-like interface and which connector pin assignments to use.

The handshaking and control lines of the interface are intended for the setup and

takedown of a dial-up communication circuit; in particular, the use of handshake lines for

flow control is not reliably implemented in many devices.

No method is specified for sending power to a device. While a small amount of current

can be extracted from the DTR and RTS lines, this is only suitable for low power devices

such as mice.

The 25-way connector recommended in the standard is large compared to current

practice.

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Standard details

In RS-232, user data is sent as a time-series of bits. Both synchronous and asynchronous

transmissions are supported by the standard. In addition to the data circuits, the standard defines

a number of control circuits used to manage the connection between the DTE and DCE. Each

data or control circuit only operates in one direction, that is, signaling from a DTE to the

attached DCE or the reverse. Since transmit data and receive data are separate circuits, the

interface can operate in a full duplex manner, supporting concurrent data flow in both directions.

The standard does not define character framing within the data stream, or character encoding.

Voltage levels

The RS-232 standard defines the voltage levels that

correspond to logical one and logical zero levels for

the data transmission and the control signal lines.

Valid signals are plus or minus 3 to 15 volts – the

range near zero volts is not a valid RS-232 level.

The standard specifies a maximum open-circuit voltage of 25 volts: signal levels of ±5 V, ±10 V,

±12 V, and ±15 V are all commonly seen depending on the power supplies available within a

device. RS-232 drivers and receivers must be able to withstand indefinite short circuit to ground

or to any voltage level up to ±25 volts. The slew rate, or how fast the signal changes between

levels, is also controlled.

For data transmission lines (TxD, RxD and their secondary channel equivalents) logic one is

defined as a negative voltage, the signal condition is called marking, and has the functional

significance. Logic zero is positive and the signal condition is termed spacing. Control signals

are logically inverted with respect to what one would see on the data transmission lines. When

one of these signals is active, the voltage on the line will be between +3 to +15 volts. The

inactive state for these signals would be the opposite voltage condition, between -3 and -15 volts.

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FIG 17: VOLTAGE CONTROL

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Examples of control lines would include request to send (RTS), clear to send (CTS), data

terminal ready (DTR), and data set ready (DSR).

(a) Connectors

RS-232 devices may be classified as Data Terminal Equipment (DTE) or Data Communication

Equipment (DCE); this defines at each device which wires will be sending and receiving each

signal. The standard recommended but did not make mandatory the D-subminiature 25 pin

connector. In general and according to the standard, terminals and computers have male

connectors with DTE pin functions, and modems have female connectors with DCE pin

functions. Other devices may have any combination of connector gender and pin definitions.

Many terminals were manufactured with female terminals but were sold with a cable with male

connectors at each end; the terminal with its cable satisfied the recommendations in the standard.

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6.4. OPTO-ISOLATOR TRAIC DRIVER (MOC3041)

The MOC3041, devices consist of gallium arsenide infrared

emitting diodes optically coupled to a monolithic silicon

detector performing the function of a Zero Voltage Crossing

bilateral triac driver. They are designed for use with a triac

in the interface of logic systems to equipment powered from

115 Vac lines, such as solid–state relays, industrial controls,

motors, solenoids and consumer appliances, etc.

• Simplifies Logic Control of 115 Vac Power

• Zero Voltage Crossing

• dv/dt of 2000 V/ms Typical, 1000 V/ms Guaranteed.

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FIG 18: MOC 3041

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Typical circuit for use when hot line switching is required. In this circuit the “hot” side of the

line is switched and the load connected to the cold or neutral side. The load may be

connected to either the neutral or hot line. Rin is calculated so that IF is equal to the rated IFT of

the part, 5 mA for the MOC3043, 10 mA for the MOC3042, or 15 mA for the MOC3041. The 39

ohm resistor and 0.01 mF capacitor are for snubbing of the triac and may or may not be

necessary depending upon the particular triac and load used.

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FIG 19: MOC 3041 CONNECTION

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6.5. TRIAC

A TRIAC, or Triode for Alternating Current is an electronic component approximately equivalent to two silicon-controlled rectifiers (SCRs/thyristors) joined in inverse parallel (paralleled but with the polarity reversed) and with their gates connected together. The formal name for a TRIAC is bidirectional triode thyristor. This results in a bidirectional electronic switch which can conduct current in either direction when it is triggered (turned on) and thus doesn't have any polarity. It can be triggered by either a positive or a negative voltage being applied to its gate electrode (with respect to T1). Once triggered, the device continues to conduct until the current through it drops below a certain threshold value, the holding current, such as at the end of a half-cycle of alternating current (AC) mains power. This makes the TRIAC a very convenient switch for AC circuits, allowing the control of very large power flows with milli-ampere-scale control currents. In addition, applying a trigger pulse at a controllable point in an AC cycle allows one to control the percentage of current that flows through the TRIAC to the load (phase control).

Triacs (BT136)

Glass passivated triacs in a plastic envelope, intended for

use in applications requiring high bidirectional transient and

blocking voltage capability and high thermal cycling perfor-

mance. Typical applications include motor control, industry-

ial and domestic lighting, heating and static switching.

PIN Configuration

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FIG 20: TRIAC

FIG 21: TRIAC PIN DISCRIPTION

FIG22: TRIAC

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6.6. OPTO-COUPLER

In electronics, an opto-isolator (or optical isolator, optical coupling device, optocoupler,

photocoupler, or photoMOS) is a device that uses a short optical transmission path to transfer

an electronic signal between elements of a circuit, typically a transmitter and a receiver, while

keeping them electrically isolated—since the electrical signal is converted to a light beam,

transferred, then converted back to an electrical signal, there is no need for electrical connection

between the source and destination circuits.

The opto-isolator is simply a package that contains both an infrared light-emitting diode (LED)

and a photo-detector such as a photosensitive silicon diode, transistor Darlington pair, or silicon

controlled rectifier (SCR). The wave-length responses of the two devices are tailored to be as

identical as possible to permit the highest measure of coupling possible. Other circuitry—for

example an output amplifier—may be integrated into the package. An opto-isolator is usually

thought of as a single integrated package, but opto-isolation can also be achieved by using

separate devices.

Configurations

A common implementation is a LED and a phototransis-

tor in a light-tight housing to exclude ambient light and

without common electrical connection, positioned so tha-

t light from the LED will impinge on the photo-detector.

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FIG 23: OPTO-COUPLER

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When an electrical signal is applied to the input of the

opto-isolator, its LED lights and illuminates the photo-

detector, producing a corresponding electrical signal in the output circuit. Unlike

a transformer the opto-isolator allows DC coupling and can provide any desired degree of

electrical isolation and protection from serious overvoltage conditions in one circuit affecting the

other. A higher transmission ratio can be obtained by using a Darlington instead of a simple

phototransistor, at the cost of reduced noise immunity and higher delay.

With a photodiode as the detector, the output current is proportional to the intensity of incident

light supplied by the emitter. The diode can be used in a photovoltaic mode or a photoconductive

mode. In photovoltaic mode, the diode acts as a current source in parallel with a forward-biased

diode. The output current and voltage are dependent on the load impedance and light intensity. In

photoconductive mode, the diode is connected to a supply voltage, and the magnitude of the

current conducted is directly proportional to the intensity of light. This optocoupler type is

significantly faster than photo transistor type, but the transmission ratio is very low; it is common

to integrate an output amplifier circuit into the same package.

The optical path may be air or a dielectric waveguide. When high noise immunity is required an

optical conductive shield can be integrated into the optical path. The transmitting and receiving

elements of an optical isolator may be contained within a single compact module, for mounting,

for example, on a circuit board; in this case, the module is often called an opto-isolator or opto-

isolator. The photo-sensor may be a photocell, phototransistor, or an optically

triggered SCR or TRIAC. This device may in turn operate a power relay or contactor.

Analog opto-isolators often have two independent, closely matched output phototransistors, one

of which is used to linearize the response using negative feedback.

Photo-Transitor Opto-Coupler (4N35)

PIN Diagram

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FIG 24: OPTO-COUPLER

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6.7. Darlington transistor

In electronics, the Darlington transistor (often called

a Darlington pair) is a compound structure consistin-

g of two bipolar transistors (either integrated or separate-

ed devices) connected in such a way that the current amp-

lified by the first transistor is amplified further by the se-

cond one. This configuration gives a much higher current gain (written β, hfe, or hFE) than each

transistor taken separately and, in the case of integrated devices, can take less space than two

individual transistors because they can use a shared collector. Integrated Darlington pairs come

packaged singly in transistor-like packages or as an array of devices (usually eight) in

an integrated circuit.

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FIG 25: POWER DARLINGTON

Unmanned Petrol Pump 2010

6.8. Solenoid valve

A solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled

by an electric current through a solenoid coil. Solenoid valves may have two or more ports: in

the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the

outflow is switched between the two outlet ports. Multiple solenoid valves can be placed

together on a manifold.

Solenoid valves are the most frequently used control elements in fluidics. Their tasks are to shut

off, release, dose, distribute or mix fluids. They are found in many application areas. Solenoids

offer fast and safe switching, high reliability, long service life, good medium compatibility of the

materials used, low control power and compact design.

Besides the plunger-type actuator which is used most frequently, pivoted-armature actuators and

rocker actuators are also used.

Working principle

A solenoid valve has two main parts:

the solenoid and the valve. The sol-

enoid converts electrical energy into

mechanical energy which, in turn, o-

pens or closes the valve mechanical-

ly. A direct acting valve has only a

small flow circuit, shown within se-

ction E of this diagram (this section

is mentioned below as a pilot valve).

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FIG 26: SOLENOID VALUE

Unmanned Petrol Pump 2010

This diaphragm piloted valve multiplies this small flow by using it to control the flow through a

much larger orifice.

Solenoid valves may use metal seals or rubber seals, and may also have electrical interfaces to

allow for easy control. A spring may be used to hold the valve opened or closed while the valve

is not activated.

The diagram to the right shows the design of a basic valve. At the top figure is the valve in its

closed state. The water under pressure enters at A. B is an elastic diaphragm and above it is a

weak spring pushing it down. The function of this spring is irrelevant for now as the valve would

stay closed even without it. The diaphragm has a pinhole through its center which allows a very

small amount of water to flow through it. This water fills the cavity C on the other side of the

diaphragm so that pressure is equal on both sides of the diaphragm. While the pressure is the

same on both sides of the diaphragm, the force is greater on the upper side which forces the

valve shut against the incoming pressure. In the figure, the surface being acted upon is greater on

the upper side which results in greater force. On the upper side the pressure is acting on the

entire surface of the diaphragm while on the lower side it is only acting on the incoming pipe.

This results in the valve being securely shut to any flow and, the greater the input pressure, the

greater the shutting force will be.

In the previous configuration the small conduit D was blocked by a pin which is the armature of

the solenoid E and which is pushed down by a spring. If the solenoid is activated by drawing the

pin upwards via magnetic force from the solenoid current, the water in chamber C will flow

through this conduit D to the output side of the valve. The pressure in chamber C will drop and

the incoming pressure will lift the diaphragm thus opening the main valve. Water now flows

directly from A to F.

When the solenoid is again deactivated and the conduit D is closed again, the spring needs very

little force to push the diaphragm down again and the main valve closes. In practice there is often

no separate spring, the elastomeric diaphragm is molded so that it functions as its own spring,

preferring to be in the closed shape.

From this explanation it can be seen that this type of valve relies on a differential of pressure

between input and output as the pressure at the input must always be greater than the pressure at

the output for it to work. Should the pressure at the output, for any reason, rise above that of the

input then the valve would open regardless of the state of the solenoid and pilot valve.

In some solenoid valves the solenoid acts directly on the main valve. Others use a small,

complete solenoid valve, known as a pilot, to actuate a larger valve. While the second type is

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Unmanned Petrol Pump 2010

actually a solenoid valve combined with a pneumatically actuated valve, they are sold and

packaged as a single unit referred to as a solenoid valve. Piloted valves require much less power

to control, but they are noticeably slower. Piloted solenoids usually need full power at all times

to open and stay open, where a direct acting solenoid may only need full power for a short period

of time to open it, and only low power to hold it.

6.9. Submersible pump

A submersible pump (or electric submersible pump (ESP)) is a device which has a hermetically

sealed motor close-coupled to the pump body. The whole assembly is submerged in the fluid to

be pumped. The main advantage of this type of pump is that it prevents pump cavitation, a

problem associated with a high elevation difference between pump and the fluid surface.

Submersible pumps push water to the surface as opposed to jet pumps having to pull water.

Submersibles are more efficient than jet pumps.

Working principle

A system of mechanical seals are used to prevent the fluid being pumped from entering the

motor and causing a short circuit. The pump can either be connected to a pipe, flexible hose or

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FIG 27: SUMERSIBLE PUMP

Unmanned Petrol Pump 2010

lowered down guide rails or wires so that the pump sits on a "ducks foot" coupling, thereby

connecting it to the delivery pipework.

Applications

Submersible pumps are found in many applications. Single stage pumps are used for drainage,

sewage pumping, general industrial pumping and slurry pumping. They are also popular with

aquarium filters. Multiple stage submersible pumps are typically lowered down a borehole and

used for water abstraction or in water wells.

Special attention to the type of ESP is required when using certain types of liquids. ESP's

commonly used on board naval vessels cannot be used to dewater contaminated flooded spaces.

These use a 440 volt A/C motor that operates a small centrifugal pump. It can also be used out of

the water, taking suction with a 2-1/2 inch non-collapsible hose. The pumped liquid is circulated

around the motor for cooling purposes. There is a possibility that the gasoline will leak into the

pump causing a fire or destroying the pump, so hot water and flammable liquids should be

avoided.

ESP usage in oil wells

Submersible pumps are used in oil production to provide a relatively efficient form of "artificial

lift", able to operate across a broad range of flow rates and depths. By decreasing the pressure at

the bottom of the well (by lowering bottom-hole flowing pressure, or increasing drawdown),

significantly more oil can be produced from the well when compared with natural production.

The pumps are typically electrically powered and referred to as Electrical Submersible Pumps

(ESP).

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Unmanned Petrol Pump 2010

ESP systems consist of both surface components (housed in the production facility, for example

an oil platform) and sub-surface components (found in the well hole). Surface components

include the motor controller (often a variable speed controller), surface cables and transformers.

Subsurface components typically include the pump, motor, seal and cables. A gas separator is

sometimes installed.

The pump itself is a multi-stage unit with the number of stages being determined by the

operating requirements. Each stage consists of a driven impeller and a diffuser which directs

flow to the next stage of the pump. Pumps come in diameters from 90mm (3.5 inches) to 254mm

(10 inches) and vary between 1 metre (3 ft) and 8.7 metres (29 ft) in length. The motor used to

drive the pump is typically a three phase, squirrel cage induction motor, with a nameplate power

rating in the range 7.5 kW to 560 kW (at 60 Hz).

New varieties of ESP can include a water/oil separator which permits the water to be reinjected

into the reservoir without the need to lift it to the surface.

The ESP system consists of a number of components that turn a staged series of centrifugal

pumps to increase the pressure of the well fluid and push it to the surface. The energy to turn the

pump comes from a high-voltage (3 to 5 kV) alternating-current source to drive a special motor

that can work at high temperatures of up to 300 °F (149 °C) and high pressures of up to 5,000 psi

(34 MPa), from deep wells of up to 12,000 feet (3.7 km) deep with high energy requirements of

up to about 1000 horsepower (750 kW). ESPs have dramatically lower efficiencies with

significant fractions of gas, greater than about 10% volume at the pump intake. Given their high

rotational speed of up to 4000 rpm (67 Hz) and tight clearances, they are not very tolerant of

solids such as sand.

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Unmanned Petrol Pump 2010

6.10. Nozzle

A nozzle is a mechanical device designed to control the direction or characteristics of

a fluid flow as it exits (or enters) an enclosed chamber or pipe via an orifice.

A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or

modify the flow of a fluid (liquid or gas). Nozzles are frequently used to control the rate of flow,

speed, direction, mass, shape, and/or the pressure of the stream that emerges from them.

Types of nozzles

Jets

A gas jet, fluid jet, or hydro jet is a nozzle intended to eject gas or fluid in a coherent stream

into a surrounding medium. Gas jets are commonly found in gas stoves, ovens, or barbecues. Gas

jets were commonly used for light before the development of electric light. Other types of fluid

jets are found in carburetors, where smooth calibrated orifices are used to regulate the flow

of fuel into an engine, and in jacuzzis or spas.

High velocity nozzles

Frequently the goal is to increase the kinetic energy of the flowing medium at the expense of

its pressure and internal energy.

Nozzles can be described as convergent (narrowing down from a wide diameter to a smaller

diameter in the direction of the flow) or divergent(expanding from a smaller diameter to a larger

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Unmanned Petrol Pump 2010

one). A de Laval nozzle has a convergent section followed by a divergent section and is often

called a convergent-divergent nozzle ("con-di nozzle").

Propelling nozzles

A jet exhaust produces a net thrust from the energy obtained from combusting fuel which is

added to the inducted air. This hot air is passed through a high speed nozzle, a propelling

nozzle which enormously increases its kinetic energy.

Magnetic nozzles

Magnetic nozzles have also been proposed for some types of propulsion, such as VASIMR, in

which the flow of plasma is directed bymagnetic fields instead of walls made of solid matter.

Spray nozzles

Many nozzles produce a very fine spray of liquids.

Atomizer nozzles are used for spray painting, perfumes, carburettors for internal

combustion engines, spray on deodorants,antiperspirants and many other uses.

Air-Aspirating Nozzle-uses an opening in the cone shaped nozzle to inject air

into a stream of water based foam (CAFS/AFFF/FFFP) to make the concentrate

"foam up". Most commonly found on foam extinguishers and foam handlines.

Swirl nozzles inject the liquid in tangentially, and it spirals into the center and

then exits through the central hole. Due to the vortexing this causes the spray to

come out in a cone shape.

Vacuum nozzles Vacuum cleaner nozzles come in several different shapes.

Shaping nozzles Some nozzles are shaped to produce a stream that is of a

particular shape. For example extrusion molding is a way of producing lengths

of metals or plastics or other materials with a particular cross-section. This nozzle

is typically referred to as a die.

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Unmanned Petrol Pump 2010

6.11. Counter

In digital logic and computing, a counter is a device which stores (and sometimes displays) the

number of times a particular event or process has occurred, often in relationship to a clock signal.

In practice, there are two types of counters:

Up counters, which increase (increment) in value

Down counters, which decrease (decrement) in value

In electronics

In electronics, counters can be implemented quite easily using register-type circuits such as the

flip-flop, and a wide variety of designs exist, e.g:

Asynchronous (ripple) counter – changing state bits are used as clocks to subsequent state

flip-flops

Synchronous counter – all state bits change under control of a single clock

Decade counter – counts through ten states per stage

Up–down counter – counts both up and down, under command of a control input

Ring counter – formed by a shift register with feedback connection in a ring

Johnson counter – a twisted ring counter

Cascaded counter

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Each is useful for different applications. Usually, counter circuits are digital in nature, and count

in natural binary. Many types of counter circuit are available as digital building blocks, for

example a number of chips in the 4000 series implement different counters. Occasionally there

are advantages to using a counting sequence other than the natural binary sequence -- such as the

binary coded decimal counter, a linear feedback shift register counter, or a Gray-code counter.

Counters are useful for digital clocks and timers, and in oven timers, VCR clocks, etc.

Asynchronous (ripple) counter

FIG 28 Asynchronous counter created from two JK flip-flops

An asynchronous (ripple) counter is a single D-type flip-flop, with its D (data) input fed from its

own inverted output. This circuit can store one bit, and hence can count from zero to one before

it overflows (starts over from 0). This counter will increment once for every clock cycle and

takes two clock cycles to overflow, so every cycle it will alternate between a transition from 0 to

1 and a transition from 1 to 0. Notice that this creates a new clock with a 50% duty cycle at

exactly half the frequency of the input clock. If this output is then used as the clock signal for a

similarly arranged D flip-flop (remembering to invert the output to the input), you will get

another 1 bit counter that counts half as fast. Putting them together yields a two bit counter:

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Cycle Q1 Q0 (Q1:Q0)dec0 0 0 01 0 1 12 1 0 23 1 1 34 0 0 0

Unmanned Petrol Pump 2010

You can continue to add additional flip-flops, always inverting the output to its own input, and

using the output from the previous flip-flop as the clock signal. The result is called a ripple

counter, which can count to 2n-1 where n is the number of bits (flip-flop stages) in the counter.

Ripple counters suffer from unstable outputs as the overflows "ripple" from stage to stage, but

they do find frequent application as dividers for clock signals, where the instantaneous count is

unimportant, but the division ratio overall is. (To clarify this, a 1-bit counter is exactly equivalent

to a divide by two circuit; the output frequency is exactly half that of the input when fed with a

regular train of clock pulses).The use of flip-flop outputs as clocks leads to timing skew between

the count data bits, making this ripple technique incompatible with normal synchronous circuit

design styles.

Synchronous counter

FIG 29 :A 4-bit synchronous counter using JK flip-flops

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A simple way of implementing the logic for each bit of an ascending counter (which is what is

depicted in the image to the right) is for each bit to toggle when all of the less significant bits are

at a logic high state. For example, bit 1 toggles when bit 0 is logic high; bit 2 toggles when both

bit 1 and bit 0 are logic high; bit 3 toggles when bit 2, bit 1 and bit 0 are all high; and so on.

Synchronous counters can also be implemented with hardware finite state machines, which are

more complex but allow for smoother, more stable transitions. Wdware-based counters are of

this type. Please note that the counter shown will have an error once it reaches 1110.

Ring counter

A ring counter is a shift register (a cascade connection of flip-flops) with the output of the last

one connected to the input of the first, that is, in a ring. Typically a pattern consisting of a single

1 bit is circulated, so the state repeats every N clock cycles if N flip-flops are used. It can be used

as a cycle counter of N states.

Johnson counter

A Johnson counter (or switchtail ring counter, twisted-ring counter, walking-ring counter, or

Moebius counter) is a modified ring counter, where the output from the last stage is inverted and

fed back as input to the first stage. A pattern of bits equal in length to twice the length of the shift

register thus circulates indefinitely. These counters find specialist applications, including those

similar to the decade counter, digital to analog conversion, etc.

Decade counter

A decade counter is one that counts in decimal digits, rather than binary. A decimal counter may

have each digit binary encoded (that is, it may count in binary-coded decimal, as the 7490

integrated circuit did) or other binary encodings (such as the bi-quinary encoding of the 7490

integrated circuit). Alternatively, it may have a "fully decoded" or one-hot output code in which

each output goes high in turn; the 4017 was such a circuit. The latter type of circuit finds

applications in multiplexers and demultiplexers, or wherever a scanning type of behavior is

cuseful. Similar counters with different numbers of outputs are also common.

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Unmanned Petrol Pump 2010

The decade counter is also known as a mod-counter.

Up–down counter

A counter that can change state in either direction, under control an up–down selector input, is

known as an up–down counter. When the selector is in the up state, the counter increments its

value; when the selector is in the down state, the counter decrements the count.

Mechanical counters

Mechanical counter wheels showing both sides. The bump

on the wheel shown at the top engages the ratchet on the

wheel below every turn. Several mechanical counters

Long before electronics became common, mechanical

devices were used to count events. These typically consist

of a series of disks mounted on an axle, with the digits 0

through 9 marked on their edge. The right most disk moves

one increment with each event. Each disk except the left-most has a protrusion that, after the

completion of one revolution, moves the next disk to the left one increment. Such counters were

originally used to control manufacturing processes, but were later used as odometers for bicycles

and cars and in fuel dispensers. One of the largest manufacturers was the Veeder-Root company,

and their name was often used for this type of counter.

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6.12. Photo resistor

A photo resistor or light dependent resistor or 

cadmium sulfide (CdS) cell is a resistor whose resistance

decreases with increasing incident light intensity. It can also

be referred to as a photoconductor.

A photo resistor is made of a high resistance semicon-

ductor. If light falling on the device is of high enough 

frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump

into the conduction band. The resulting free electron (and its hole partner) conduct electricity,

thereby lowering resistance.

A photoelectric device can be either intrinsic or extrinsic. An intrinsic semiconductor has its

own charge carriers and is not an efficient semiconductor, e.g. silicon. In intrinsic devices the

only available electrons are in the valence band, and hence the photon must have enough energy

to excite the electron across the entire bandgap. Extrinsic devices have impurities, also

called dopants, added whose ground state energy is closer to the conduction band; since the

electrons do not have as far to jump, lower energy photons (i.e., longer wavelengths and lower

frequencies) are sufficient to trigger the device. If a sample of silicon has some of its atoms

replaced by phosphorus atoms (impurities), there will be extra electrons available for conduction.

This is an example of an extrinsic semiconductor.

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FIG 31:LDR

Unmanned Petrol Pump 2010

7. WORKING OF UNMANNED PETROL PUMP

BLOCK DIAGRAM OF UNMANNED PETROL PUMP

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Unmanned Petrol Pump 2010

FIG 32: BLOCK DIAGRAM OF UPP

7.1. INTERNAL WORKING OF UNMANNED PETROL PUMP

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FUEL TANK

VIDEO UNIT

MICROPROCE-SSOR AND NETWORK INTERFACE

MICROCONT-ROLLER-PIC16F72

OTHER ELECTRONICS COMPONENTS

COUNTER LEVEL INDICATOR SUBMERSIBLE PUMP

Unmanned Petrol Pump 2010

The unmanned petrol pump is the electronic based pump, to easy the use of the pump for the

customer. It also provides the mobility to the server to serve the customer through the control

unit and also provide control over petrol pump working. The control unit also keeps the control

over the quantity stored in the fuel dispenser, commanding to the microcontroller, filling and

also restores the micro-controller.

So, after receiving the task of filling the tank of automobile.

It provides the level of fuel stored at the fuel dispenser by checking the level of the level indicator

(this indicator is based on light dependent resistor). This input is received at the port A of the

microcontroller. The microcontroller manipulates the level through the internal program, and

then it sends the value to the control unit via network interface which is connected to the desktop

computer used in fuel dispenser end.

Now, when the microcontroller received the command to fulfill the requirement of the fuel to

customer up to the specific value provided the customer. Then microcontroller gives a signal to

the MOC-3041, which is an input of 5V. The MOC-3041 is connected to the port C of the

microcontroller. This pin is kept high till the pump value could not be achieved to that value.

Till the MOC-3041 is provided the high signal it provide the high signal to the AC control circuit

which is connected to the submersible pump, which provides the outlet flow of the fuel.

To let the customer to know how much fuel is filled to the tank, a counter is provided to the fuel

dispenser. To run the counter micro-controller provides the high signal to the DC control circuit

till the pump signal is kept high. This signal is provided by another micro-controller pin of port

C.

After completion of the task microcontroller provide the signal of task completion to the control

unit. This signal via serial port of desktop computer connected to the micro-controller. The

signal is passed to the control unit via interface unit desktop computer.

AC control circuit

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Unmanned Petrol Pump 2010

DC control circuit

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R1 1o K 1 Watt Resistor

R2 1o0 K Potentiometer (Variable Resistance)

C1 0.1 uF (500V or above ) Polyester Capacitor

T1 BT 136 Triac

D1 DB2 Diac

FIG 33: AC Control Circuit

Unmanned Petrol Pump 2010

8. SOFTWARE

8.1. Micro-controller programmer: PICBASIC

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FIG 34: DC Control Circuit

Unmanned Petrol Pump 2010

FIG 35: PICBASIC

Simplicity and ease which higher programming languages bring in, as well as broad application

of microcontrollers today, were reasons to incite some companies to adjust and upgrade BASIC

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Unmanned Petrol Pump 2010

programming language to better suit needs of microcontroller programming. What did we

thereby get? First of all, developing applications is faster and easier with all the predefined

routines which BASIC brings in, whose programming in assembly would take the largest amount

of time. This allows programmer to concentrate on solving the important tasks without wasting

his time on, say, code for printing on LCD display.

Programming language is a set of commands and rules according to which we write the

program. There are various programming languages such as BASIC, C, Pascal, etc. There

is plenty of resources on BASIC programming language out there, so we will focus our

attention particularly to programming of microcontrollers.

Program consists of a sequence of commands written in programming language that

microcontroller executes one after another.

Compiler is a program run on computer and its task is to translate the original BASIC

code into language of zeros and ones that can be fed to microcontroller. The process of

translation of BASIC program into executive HEX code is shown in the figure below.

The program written in BASIC and saved as file program.pbas is converted by compiler

into assembly code (program.asm). The generated assembly code is further translated into

executive HEX code which can be written to microcontroller memory.

Programmer is a device which we use to transfer our HEX files from computer to

microcontroller memory.

8.2. Computer Programming: Visual Basic 6

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Like the BASIC programming language, Visual Basic was designed to be easily learned and

used by beginner programmers. The language not only allows programmers to create

simple GUI applications, but can also develop complex applications. Programming in VB is a

combination of visually arranging components or controls on a form, specifying attributes and

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FIG 36: Visual basic 6

Unmanned Petrol Pump 2010

actions of those components, and writing additional lines of code for more functionality. Since

default attributes and actions are defined for the components, a simple program can be created

without the programmer having to write many lines of code. Performance problems were

experienced by earlier versions, but with faster computers and native code compilation this has

become less of an issue.

Although programs can be compiled into native code executables from version 5 onwards, they

still require the presence of runtime libraries of approximately 1 MB in size. This runtime is

included by default in Windows 2000 and later, but for earlier versions of Windows like

95/98/NT it must be distributed together with the executable.

Forms are created using drag-and-drop techniques. A tool is used to place controls (e.g., text

boxes, buttons, etc.) on the form (window). Controls have attributes and event

handlers associated with them. Default values are provided when the control is created, but may

be changed by the programmer. Many attribute values can be modified during run time based on

user actions or changes in the environment, providing a dynamic application. For example, code

can be inserted into the form resize event handler to reposition a control so that it remains

centered on the form, expands to fill up the form, etc. By inserting code into the event handler

for a keypress in a text box, the program can automatically translate the case of the text being

entered, or even prevent certain characters from being inserted.

Visual Basic can create executables (EXE files), ActiveX controls, or DLL files, but is primarily

used to develop Windows applications and to interface database systems. Dialog boxes with less

functionality can be used to provide pop-up capabilities. Controls provide the basic functionality

of the application, while programmers can insert additional logic within the appropriate event

handlers. For example, a drop-down combination box will automatically display its list and allow

the user to select any element. An event handler is called when an item is selected, which can

then execute additional code created by the programmer to perform some action based on which

element was selected, such as populating a related list.

Alternatively, a Visual Basic component can have no user interface, and instead provide ActiveX

objects to other programs via Component Object Model (COM). This allows for server-

side processing or an add-in module.

The language is garbage collected using reference counting, has a large library of utility objects,

and has basic object oriented support. Since the more common components are included in the

default project template, the programmer seldom needs to specify additional libraries. Unlike

many other programming languages, Visual Basic is generally not case sensitive, although it will

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Unmanned Petrol Pump 2010

transform keywords into a standard case configuration and force the case of variable names to

conform to the case of the entry within the symbol table. String comparisons are case sensitive

by default, but can be made case insensitive if so desired.

The Visual Basic compiler is shared with other Visual Studio languages (C, C++), but

restrictions in the IDE do not allow the creation of some targets (Windows model DLLs) and

threading models.

9. PROBLEM FACED DURING DESIGNING

Un-availability of the resources.

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Many electronics components are not available in Market.

Typical to design.

Different type of design available, but due to unavailability of resources it lead to difficulty in designing.

Difficult to Fabricate

Due the difference in theory and practical in subject, it is difficult to fabricate.

Difficulty at the microcontroller programming end

Deep study is done at programming end, to program a micro—controller.

Difficulty at the computer programming end

Unawareness about the computer programming on VB6.

Hard to find the microcontroller programmer

Only few microcontroller programmer are available, and expensive to buy a micro-controller programmer.

10. FUTURE APPLICATION

Unmanned petrol station was required for over the years to fulfill the requirement of consumers over the wide area.

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Unmanned Petrol Pump 2010

Unmanned petrol station concept is not limited petrol station, but it can be applicable for the availability of food grades at long distinct area.

It can make human more safe from robbery, fraud, and any other unwanted incidences by the use of plastic money.

10. CONCLUSION

The project Unmanned Petrol Pump is a successful, with our knowledge provided during our

academics and with the concerned to the faculty. During our project we learnt about many

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Unmanned Petrol Pump 2010

components used in our project. This project could not be a successful if hard work and patience

was not devoted to it.

This project had bridged the gap between the theory and the practical about the subject. This

project taught us about many realistic things such as Management, Time Work.

APPENDIX-A

PROGRAMMING OF MICRO-CONTROLLER ON PICBASIC

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device 16c72

xtal = 4

input porta

output portb

output portc

DECLARE SERIAL_BAUD 300

DECLARE RSOUT_PIN portc.1

DECLARE RSIN_PIN portc.0

Dim l1 As Byte

Dim l2 As Byte

Dim l3 As Byte

Dim l4 As Byte

Dim

inval as Byte

low portc.3

low portc.4

Loop:

inval = rsin

if inval="A" then goto rl1

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Unmanned Petrol Pump 2010

if inval="B" then goto rl2

if inval="C" then goto rl3

if inval="H" then goto rl4

if inval="X" then goto rxd

goto loop

rl1:

toggle portc.3

goto loop

rl2:

toggle portc.4

goto loop

rl4:

rsout "Automatic Petrol Pump"

rsout 10

rsout 13

rsout "Press A to Control Pump"

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Unmanned Petrol Pump 2010

rsout 10

rsout 13

rsout "press B to Control Counter"

rsout 10

rsout 13

rsout "Press H as Help"

rsout 10

rsout 13

rsout "press X to get Level"

rsout 10

rsout 13

goto loop

rl3:

toggle portb.4

goto loop

rxd:

l1=adin 0

delayms 50

rsout "The level in tank is"

Page | 81

Unmanned Petrol Pump 2010

rsout 10

rsout 13

rsout dec l1

rsout 10

rsout 13

goto loop

Page | 82