main project documentation

IMPLEMENTING SECURITY IN INDUSTRIAL AUTOMATION

CHAPTER-1

INTRODUCTION:

The aim of this project is used for automation of mechatronic processes, such as control of

machinery on factory assembly lines, control of amusement rides, or control of lighting fixtures.

More recently electricity has been used for control and early electrical control was based on relays.

These relays allow power to be switched on and off without a mechanical switch. It is common to

use relays to make simple logical control decisions.

These systems are being advanced by ongoing research and development activities;

one major activity entails the application with sensors to material-handling,

inspection, and assembly operations.

1


CHAPTER-2

EMBEDDED SYSYTEMS

2.1: Introduction to Embedded System:

Embedded system is the combination of both software and hardware. A embedded system is a system which is going to do a predefined specified task is the embedded system and is even defined as combination of both software and hardware

A general-purpose definition of embedded systems is that they are devices used to

control, monitor or assist the operation of equipment, machinery or plant.

"Embedded" reflects the fact that they are an integral part of the system. In many

cases their embedded may be such that their presence is far from obvious to the

casual observer and even the more technically skilled might need to examine the

operation of a piece of equipment for some time before being able to conclude that an

embedded control system was involved in its functioning. At the other extreme a

general-purpose computer may be used to control the operation of a large complex

processing plant, and its presence will be obvious.

All embedded systems are including computers or microprocessors. Some of these

computers are however very simple systems as compared with a personal computer.

The very simplest embedded systems are capable of performing only a single function

or set of functions to meet a single predetermined purpose. In more complex systems

an application program that enables the embedded system to be used for a particular

purpose in a specific application determines the functioning of the embedded system.

The ability to have programs means that the same embedded system can be used for a

variety of different purposes. In some cases a microprocessor may be designed in

such a way that application software for a particular purpose can be added to the basic

software in a second process, after which it is not possible to make further changes.

The applications software on such processors is sometimes referred to as firmware

2

Embedded System

Software Hardware

ALPCVB Etc.,

ProcessorPeripheralsmemory


The simplest devices consist of a single microprocessor (often called a "chip”), which

may itself be packaged with other chips in a hybrid system or Application Specific

Integrated Circuit (ASIC). Its input comes from a detector or sensor and its output

goes to a switch or activator which (for example) may start or stop the operation of a

machine or, by operating a valve, may control the flow of fuel to an engine.

Block diagram of Embedded System:

FIG 2.1.1: BLOCK DIAGRAM OF EMBEDDED SYSTEM

Software deals with the languages like ALP, C, and VB etc., and Hardware deals with

Processors, Peripherals, and Memory.

Memory: It is used to store data or address.

Peripherals: These are the external devices connected

Processor: It is an IC which is used to perform some task

Processors are classified into four types like:

1. Micro Processor (µp)

2. Micro controller (µc)

3. Digital Signal Processor (DSP)

3

EEPROM, ADC, DAC, Timers,

USART, OscillatorsEtc.,

ALU

CU

Memory


4. Application Specific Integrated Circuits (ASIC)

Micro Processor (µp):

It is an electronic chip which performs arithmetic and logical operations with

assistance of internal memory.

Block Diagram of Micro Processor (µp):

ALU

CU

MEMORY

FIG 2.1.2: BLOCK DIAGRAM OF MICRO PROCESSOR (µP)

Micro Controller (µc):

It is a highly integrated micro processor designed for specific use in embedded

systems.

Block Diagram of Micro Controller (µc):

FIG 2.1.3: BLOCK DIAGRAM OF MICRO CONTROLLER (µC)

4


Digital Signal Processor (DSP):

It is the study of signals in digital representation and processing methods of

these signals. It is used where large mathematical and scientific calculations are

required.

Application Specific Integrated circuits (ASIC):

It is an IC designed for a specific application. This IC designed for specific

application can’t be used for other applications.

5


CHAPTER-3

HARDWARE DESCRIPTION

3.1: INTRODUCTION WITH BLOCK DIAGRAM:

1. THEFT IDENTIFICATION:

6


2. AUTOMATIC VEHICLE PARKING:

7


3. STREET LIGHTING:

LM393

GND

4. FIRE ALARM:

LM393

GND

8

LDR

+

POT

THERMISTOR

+

POT


3.2: MICROCONTROLLER AT89S52:

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with

8K bytes of in-system programmable Flash memory. The device is manufactured

using Atmel’s high-density non volatile memory technology and is compatible with

the industry standard 80C51 instruction set and pin out. The on-chip Flash allows the

program memory to be reprogrammed in-system or by a conventional non volatile

memory programmer. By combining a versatile 8-bit CPU with in-system

programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful

microcontroller which provides a highly-flexible and cost-effective solution to many

embedded control applications.

The AT89S52 provides the following standard features: 8K bytes of Flash, 256 bytes

of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters,

a six-vector two-level interrupt architecture, a full duplex serial port, on-chip

oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic

for operation down to zero frequency and supports two software selectable power

saving modes. The Idle Mode stops the CPU while allowing the RAM,

timer/counters, serial port, and interrupt system to continue functioning. The Power-

down mode saves the RAM contents but freezes the oscillator, disabling all other chip

functions until the next interrupt or hardware reset.

Features:

• Compatible with MCS®-51 Products

• 8K Bytes of In-System Programmable (ISP) Flash Memory

– Endurance: 10,000 Write/Erase Cycles

• 4.0V to 5.5V Operating Range

• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

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• 256 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Three 16-bit Timer/Counters

• Eight Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

• Interrupt Recovery from Power-down Mode

• Watchdog Timer

• Dual Data Pointer

• Power-off Flag

• Fast Programming Time

• Flexible ISP Programming (Byte and Page Mode)

• Green (Pb/Halide-free) Packaging Option

Block Diagram of AT89S52:

FIG 3.2.1: BLOCK DIAGRAM OF AT89S52

10


Pin Configurations of AT89S52:

FIG 3.2.2: PIN DIAGRAM OF AT89S52

Pin Description:

VCC: Supply voltage.

GND: Ground.

Port 0:

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can

sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as

high-impedance inputs. Port 0 can also be configured to be the multiplexed low-order

address/data bus during accesses to external program and data memory. In this mode,

P0 has internal pull-ups. Port 0 also receives the code bytes during Flash

programming and outputs the code bytes during program verification. External pull-

ups are required during program verification.

Port 1:

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output

buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are

pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins

11


that are externally being pulled low will source current (IIL) because of the internal

pull-ups. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2

external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX).

Port 2:




that are externally being pulled low will source current (IIL) because of the internal

pull-ups. Port 2 emits the high-order address byte during fetches from external

program memory and during accesses to external data memory that uses 16-bit

addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups

when emitting 1s. During accesses to external data memory that uses 8-bit addresses

(MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register.

Port 3:




that are externally being pulled low will source current (IIL) because of the pull-ups.

RST:

Reset input. A high on this pin for two machine cycles while the oscillator is running

resets the device. This pin drives high for 98 oscillator periods after the Watchdog

times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this

feature. In the default state of bit DISRTO, the RESET HIGH out feature is enabled.

ALE/PROG:

Address Latch Enable (ALE) is an output pulse for latching the low byte of the

address during accesses to external memory. This pin is also the program pulse input

12


(PROG) during Flash programming. In normal operation, ALE is emitted at a

constant rate of 1/6 the oscillator frequency and may be used for external timing or

clocking purposes. Note, however, that one ALE pulse is skipped during each access

to external data memory.

PSEN:

Program Store Enable (PSEN) is the read strobe to external program memory. When

the AT89S52 is executing code from external program memory, PSEN is activated

twice each machine cycle, except that two PSEN activations are skipped during each

access to external data memory.

EA/VPP:

External Access Enable. EA must be strapped to GND in order to enable the device to

fetch code from external program memory locations starting at 0000H up to FFFFH.

Note, however, that if lock bit 1 is programmed, EA will be internally latched on

reset. EA should be strapped to VCC for internal program executions. This pin also

receives the 12-volt programming enable voltage (VPP) during Flash programming.

XTAL1:

Input to the inverting oscillator amplifier and input to the internal clock operating

circuit.

XTAL2:

Output from the inverting oscillator amplifier

Oscillator Characteristics:

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier

which can be configured for use as an on-chip oscillator, as shown in Figure 1. Either

a quartz crystal or ceramic resonator may be used. To drive the device from an

external clock source, XTAL2 should be left unconnected while XTAL1 is driven as

13


shown in Figure 6.2. There are no requirements on the duty cycle of the external

clock signal, since the input to the internal clocking circuitry is through a divide-by-

two flip-flop, but minimum and maximum voltage high and low time specifications

must be observed.

FIG 3.2.3: OSCILLATOR CONNECTIONS

FIG 3.2.4: EXTERNAL CLOCK DRIVE CONFIGURATION

Idle Mode:

In idle mode, the CPU puts itself to sleep while all the on chip peripherals remain

active. The mode is invoked by software. The content of the on-chip RAM and all the

special functions registers remain unchanged during this mode. The idle mode can be

terminated by any enabled interrupt or by a hardware reset.

14


Power down Mode:

In the power down mode the oscillator is stopped, and the instruction that invokes

power down is the last instruction executed. The on-chip RAM and Special Function

Registers retain their values until the power down mode is terminated. The only exit

from power down is a hardware reset. Reset redefines the SFRs but does not change

the on-chip RAM. The reset should not be activated before VCC is restored to its

normal operating level and must be held active long enough to allow the oscillator to

restart and stabilize.

3.3 REGULATED POWER SUPPLY:

Power supply is a supply of electrical power. A device or system that supplies electrical

or other types of energy to an output load or group of loads is called a power supply

unit or PSU. The term is most commonly applied to electrical energy supplies, less

often to mechanical ones, and rarely to others.

A power supply may include a power distribution system as well as primary or

secondary sources of energy such as

Conversion of one form of electrical power to another desired form and

voltage, typically involving converting AC line voltage to a well-regulated

lower-voltage DC for electronic devices. Low voltage, low power DC power

supply units are commonly integrated with the devices they supply, such

as computers and household electronics.

Batteries.

Chemical fuel cells and other forms of energy storage systems.

Solar power.

Generators or alternators.

15


Block Diagram:

FIG 3.3.1 REGULATED POWER SUPPLY

The basic circuit diagram of a regulated power supply (DC O/P) with led connected

as load is shown in fig: 3.3.2.

FIG 3.3.2 CIRCUIT DIAGRAM OF REGULATED POWER SUPPLY WITH

LED CONNECTION

The components mainly used in above figure are:

230V AC MAINS

TRANSFORMER

BRIDGE RECTIFIER(DIODES)

CAPACITOR

VOLTAGE REGULATOR(IC 7805)

RESISTOR

16


LED(LIGHT EMITTING DIODE)

The detailed explanation of each and every component mentioned above is as

follows:

Transformation: The process of transforming energy from one device to another is

called transformation. For transforming energy we use transformers.

Transformers: A transformer is a device that transfers electrical energy from

one circuit to another through inductively coupled conductors without changing its

frequency. A varying current in the first or primary winding creates a

varying magnetic flux in the transformer's core, and thus a varying magnetic

field through the secondary winding. This varying magnetic field induces a

varying electromotive force (EMF) or "voltage" in the secondary 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. This field is made up from lines of force and has the same

shape as a bar magnet.

If the current is increased, the lines of force move outwards from the coil. If the

current is reduced, the lines of force move inwards.

If another coil is placed adjacent to the first coil then, as the field moves out or in, the

moving lines of force will "cut" the turns of the second coil. As it does this, a voltage

is induced in the second coil. With the 50 Hz AC mains supply, this will happen 50

times a second. This is called MUTUAL INDUCTION and forms the basis of the

transformer.

The input coil is called the PRIMARY WINDING; the output coil is the

SECONDARY WINDING. Fig: 3.3.4 shows step-down transformer.

17


FIG 3.3.3: STEP-DOWN TRANSFORMER

The voltage induced in the secondary is determined by the TURNS RATIO.

For example, if the secondary has half the primary turns; the secondary will have half

the primary voltage.

Another example is if the primary has 5000 turns and the secondary has 500 turns,

then the turn’s ratio is 10:1.

If the primary voltage is 240 volts then the secondary voltage will be x 10 smaller =

24 volts. Assuming a perfect transformer, the power provided by the primary must

equal the power taken by a load on the secondary. If a 24-watt lamp is connected

across a 24 volt secondary, then the primary must supply 24 watts.

To aid magnetic coupling between primary and secondary, the coils are wound on a

metal CORE. Since the primary would induce power, called EDDY CURRENTS,

into this core, the core is LAMINATED. This means that it is made up from metal

sheets insulated from each other. Transformers to work at higher frequencies have an

iron dust core or no core at all.

18


Note that the transformer only works on AC, which has a constantly changing current

and moving field. DC has a steady current and therefore a steady field and there

would be no induction.

Some transformers have an electrostatic screen between primary and secondary. This

is to prevent some types of interference being fed from the equipment down into the

mains supply, or in the other direction. Transformers are sometimes used for

IMPEDANCE MATCHING.

We can use the transformers as step up or step down.

Step Up transformer: In case of step up transformer, primary windings are every

less compared to secondary winding.

Because of having more turns secondary winding accepts more energy, and it

releases more voltage at the output side.

Step down transformer: In case of step down transformer, Primary winding induces

more flux than the secondary winding, and secondary winding is having less number

of turns because of that it accepts less number of flux, and releases less amount of

voltage.

Battery power supply: A battery is a type of linear power supply that offers benefits

that traditional line-operated power supplies lack: mobility, portability and reliability.

A battery consists of multiple electrochemical cells connected to provide the voltage

desired. Fig: 3.3.5 shows Hi-Watt 9V battery

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http://en.wikipedia.org/wiki/Battery_(electricity)


FIG 3.3.4: HI-WATT 9V BATTERY

The most commonly used dry-cell battery is the carbon-zinc dry cell battery. Dry-cell

batteries are made by stacking a carbon plate, a layer of electrolyte paste, and a zinc

plate alternately until the desired total voltage is achieved. The most common dry-cell

batteries have one of the following voltages: 1.5, 3, 6, 9, 22.5, 45, and 90. During the

discharge of a carbon-zinc battery, the zinc metal is converted to a zinc salt in the

electrolyte, and magnesium dioxide is reduced at the carbon electrode. These actions

establish a voltage of approximately 1.5 V.

The lead-acid storage battery may be used. This battery is rechargeable; it consists of

lead and lead/dioxide electrodes which are immersed in sulphuric acid. When fully

charged, this type of battery has a 2.06-2.14 V potential (A 12 volt car battery uses 6

cells in series). During discharge, the lead is converted to lead sulphate and the

sulphuric acid is converted to water. When the battery is charging, the lead sulphate is

converted back to lead and lead dioxide A nickel-cadmium battery has become more

popular in recent years. This battery cell is completely sealed and rechargeable. The

electrolyte is not involved in the electrode reaction, making the voltage constant over

the span of the batteries long service life. During the charging process, nickel oxide is

oxidized to its higher oxidation state and cadmium oxide is reduced. The nickel-

cadmium batteries have many benefits. They can be stored both charged and

uncharged. They have a long service life, high current availabilities, constant voltage,

and the ability to be recharged. Fig: 3.3.6 shows pencil battery of 1.5V.

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http://en.wikipedia.org/wiki/Nickel-cadmium

http://en.wikipedia.org/wiki/Car_battery

http://en.wikipedia.org/wiki/Lead-acid

http://en.wikipedia.org/wiki/Carbon-zinc

http://en.wikipedia.org/wiki/Dry-cell


FIG 3.3.5: PENCIL BATTERY OF 1.5V

RECTIFICATION: The process of converting an alternating current to a pulsating

direct current is called as rectification. For rectification purpose we use rectifiers.

Rectifiers: A rectifier is an electrical device that converts alternating current (AC) to

direct current (DC), a process known as rectification. Rectifiers have many uses

including as components of power supplies and as detectors of radio signals.

Rectifiers may be made of solid-state diodes, vacuum tube diodes, mercury arc

valves, and other components.

A device that it can perform the opposite function (converting DC to AC) is known as

an inverter.

When only one diode is used to rectify AC (by blocking the negative or positive

portion of the waveform), the difference between the term diode and the term rectifier

is merely one of usage, i.e., the term rectifier describes a diode that is being used to

convert AC to DC. Almost all rectifiers comprise a number of diodes in a specific

arrangement for more efficiently converting AC to DC than is possible with only one

diode. Before the development of silicon semiconductor rectifiers, vacuum tube

diodes and copper (I) oxide or selenium rectifier stacks were used.

Bridge full wave rectifier: The Bridge rectifier circuit is shown in fig: 3.3.7, which

converts an ac voltage to dc voltage using both half cycles of the input ac voltage.

21


The Bridge rectifier circuit is shown in the figure. The circuit has four diodes

connected to form a bridge. The ac input voltage is applied to the diagonally opposite

ends of the bridge. The load resistance is connected between the other two ends of the

bridge.

For the positive half cycle of the input ac voltage, diodes D1 and D3 conduct,

whereas diodes D2 and D4 remain in the OFF state. The conducting diodes will be in

series with the load resistance RL and hence the load current flows through RL.

For the negative half cycle of the input ac voltage, diodes D2 and D4 conduct

whereas, D1 and D3 remain OFF. The conducting diodes D2 and D4 will be in series

with the load resistance RL and hence the current flows through RL in the same

direction as in the previous half cycle. Thus a bi-directional wave is converted into a

unidirectional wave.

FIG 3.3.6: BRIDGE RECTIFIER

3.4: PIR SENSORS:

A Passive Infra Red sensor (PIR sensor) is an electronic device that measures infrared

(IR) light radiating from objects in its field of view. PIR sensors are often used in the

construction of PIR-based motion detectors . Apparent motion is detected when an

infrared source with one temperature, such as a human, passes in front of an infrared

source with another temperature, such as a wall.

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http://en.wikipedia.org/wiki/Wall

http://en.wikipedia.org/wiki/Human

http://en.wikipedia.org/wiki/Temperature

http://en.wikipedia.org/wiki/Motion_detector

http://en.wikipedia.org/wiki/Infrared

http://en.wikipedia.org/wiki/Electronic_device


All objects emit what is known as black body radiation. It is usually infrared radiation

that is invisible to the human eye but can be detected by electronic devices designed

for such a purpose. The term passive in this instance means that the PIR device does

not emit an infrared beam but merely passively accepts incoming infrared radiation.

“Infra” meaning below our ability to detect it visually, and “Red” because this colour

represents the lowest energy level that our eyes can sense before it becomes invisible.

Thus, infrared means below the energy level of the colour red, and applies to many

sources of invisible energy.

The PIR (Passive Infra-Red) Sensor is a pyroelectric device that detects motion by

measuring changes in the infrared levels emitted by surrounding objects. This motion

can be detected by checking for a high signal on a single I/O pin.

Features:

Single bit output

Small size makes it easy to conceal

Compatible with all Parallax microcontrollers

Theory of Operation:

Pyroelectric devices, such as the PIR sensor, have elements made of a crystalline

material that generates an electric charge when exposed to infrared radiation. The

changes in the amount of infrared striking the element change the voltages generated,

which are measured by an on-board amplifier. The device contains a special filter

called a Fresnel lens, which focuses the infrared signals onto the element. As the

ambient infrared signals change rapidly, the on-board amplifier trips the output to

indicate motion.

Pin Definitions and Ratings:

Pin Name Function

23

http://en.wikipedia.org/wiki/Eye

http://en.wikipedia.org/wiki/Black_body_radiation


- GND Connects to Ground or Vss.

+ V+ Connects to +5 VDC or Vdd.

OUT Output Connects to an I/O pin set to INPUT mode

Once the sensor warms up (settles) the output will remain low until there is motion, at

which time the output will swing high for a couple of seconds, then return low. If

motion continues the output will cycle in this manner until the sensors line of sight of

still again

Calibration:

The PIR Sensor requires a ‘warm-up’ time in order to function properly. This is due

to the settling time involved in ‘learning’ its environment. This could be anywhere

from 10-60 seconds. During this time there should be as little motion as possible in

the sensors field of view.

Sensitivity:

The PIR Sensor has a range of approximately 20 feet. This can vary with

environmental conditions. The sensor is designed to adjust to slowly changing

conditions that would happen normally as the day progresses and the environmental

conditions change, but responds by toggling its output when sudden changes occur,

such as when there is motion..

3.5: LIGHT SENSOR:

Light Dependent Resistor (LDR) also known as photoconductor or photocell, is a

device which has a resistance which varies according to the amount of light falling on

its surface. Since LDR is extremely sensitive in visible light range, it is well suited for

the proposed application.

24


FIG 3.5.1: LIGHT DEPENDENT RESISTOR

Features of the light sensor:

The Light Dependent Resistor (LDR) is made using the semiconductor Cadmium Sulphide (CdS).

The light falling on the brown zigzag lines on the sensor causes the resistance of the device to fall. This is known as a negative co-efficient. There are some LDRs that work in the opposite way i.e. their resistance increases with light (called positive coefficient).

The resistance of the LDR decreases as the intensity of the light falling on it increases.

Incident photons drive electrons from the valence band into the conduction band.

Fig3.5.2: Structure of a Light Dependent Resistor, showing Cadmium Sulphide track and an atom to illustrate electrons in the valence and conduction bands

Functional description:

• An LDR and a normal resistor are wired in series across a voltage, as

shown in the circuit below. Depending on which is tied to the 5V and

which to 0V, the voltage at the point between them, call it the sensor node,

25


will either rise or fall with increasing light. If the LDR is the component

tied directly to the 5V, the sensor node will increase in voltage with

increasing light

• The LDR's resistance can reach 10 k ohms in dark conditions and about

100 ohms in full brightness.

• The circuit used for sensing light in our system uses a 10 kΩ fixed

resistor which is tied to +5V. Hence the voltage value in this case decreases

with increase in light intensity.

FIG3.5.3: LIGHT SENSOR CIRCUIT

• The sensor node voltage is compared with the threshold voltages for

different levels of light intensity corresponding to the four conditions-

Optimum, dim, dark and night.

• The relationship between the resistance RL and light intensity

Lux for a typical LDR

RL = 500 / Lux kΩ ………………….(4.1)

•With the LDR connected to 5V through a 10K resistor, the output voltage of the LDRis:

26


Vo = 5*RL / (RL+10) (4.2)

• In order to increase the sensitivity of the sensor we must reduce the value of

the fixed resistor in series with the sensor. This may be done by putting

other resistors in parallel with it.

3.6: DC MOTOR

A DC motor is an electric motor that runs on direct current (DC) electricity. In any

electric motor, operation is based on simple electromagnetism. A current-carrying

conductor generates a magnetic field; when this is then placed in an external magnetic

field, it will experience a force proportional to the current in the conductor, and to the

strength of the external magnetic field. As you are well aware of from playing with

magnets as a kid, opposite (North and South) polarities attract, while like polarities

(North and North, South and South) repel. The internal configuration of a DC motor

is designed to harness the magnetic interaction between a current-carrying conductor

and an external magnetic field to generate rotational motion.

Let's start by looking at a simple 2-pole DC electric motor (here red represents a

magnet or winding with a "North" polarization, while green represents a magnet or

winding with a "South" polarization).

FIG 3.6.1: DC MOTOR

Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator,

commutator, field magnet(s), and brushes. In most common DC motors, the external

magnetic field is produced by high-strength permanent magnets. The stator is the

27

http://encyclobeamia.solarbotics.net/articles/dc.html


http://encyclobeamia.solarbotics.net/articles/current.html





stationary part of the motor -- this includes the motor casing, as well as two or more

permanent magnet pole pieces. The rotor rotates with respect to the stator. The rotor

consists of windings (generally on a core), the windings being electrically connected

to the commutator. The above diagram shows a common motor layout -- with the

rotor inside the stator (field) magnets.

The geometry of the brushes, commutator contacts, and rotor windings are such that

when power is applied, the polarities of the energized winding and the stator

magnet(s) are misaligned, and the rotor will rotate until it is almost aligned with the

stator's field magnets. As the rotor reaches alignment, the brushes move to the next

commutator contacts, and energize the next winding. Given our example two-pole

motor, the rotation reverses the direction of current through the rotor winding, leading

to a "flip" of the rotor's magnetic field, driving it to continue rotating.

In real life, though, DC motors will always have more than two poles (three is a very

common number). In particular, this avoids "dead spots" in the commutator. You can

imagine how with our example two-pole motor, if the rotor is exactly at the middle of

its rotation (perfectly aligned with the field magnets), it will get "stuck" there.

Meanwhile, with a two-pole motor, there is a moment where the commutator shorts

out the power supply (i.e., both brushes touch both commutator contacts

simultaneously). This would be bad for the power supply, waste energy, and damage

motor components as well. Yet another disadvantage of such a simple motor is that it

would exhibit a high amount of torque "ripple".

So since most small DC motors are of a three-pole design, let's tinker with the

workings of one via an interactive animation.

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http://encyclobeamia.solarbotics.net/articles/torque.html




You'll notice a few things from this -- namely, one pole is fully energized at a time

(but two others are "partially" energized). As each brush transitions from one

commutator contact to the next, one coil's field will rapidly collapse, as the next coil's

field will rapidly charge up. We'll see more about the effects of this later, but in the

meantime you can see that this is a direct result of the coil windings' series wiring.

3.7: MOTOR DRIVER (L293D)

Features:

Wide supply-voltage range: 4.5V to 36V

Separate input- logic supply

Internal ESD protection

Thermal shutdown

High-Noise-Immunity input

Functional Replacements for SGS L293 and SGS L293D

Output current 1A per channel (600 mA for L293D)

Peak output current 2 A per channel (1.2 A for L293D)

Output clamp diodes for Inductive Transient Suppression(L293D)

The L293 and L293D are quadruple high-current half-H drivers. The L293 is

designed to provide bidirectional drive currents of up to 1 A at voltages from 4.5 V to

36 V. The L293D is designed to provide bidirectional drive currents of up to 600-mA

at voltages from 4.5 V to 36 V. Both devices are designed to drive inductive loads

such as relays, solenoids, dc and bipolar stepping motors, as well as other high-

current/high-voltage loads in positive-supply applications.

29


FIG 3.7.1: L293D PIN DIAGRAM

All inputs are TTL compatible. Each output is a complete totem-pole drive circuit,

with a Darlington transistor sink and a pseudo-Darlington source. Drivers are enabled

in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by

3,4EN.When an enable input is high, the associated drivers are enabled and their

outputs are active and in phase with their inputs. When the enable input is low, those

drivers are disabled and their outputs are off and in the high-impedance state. With

the proper data inputs, each pair of drivers forms a full-H (or bridge) reversible drive

suitable for solenoid or motor applications.

On the L293, external high-speed output clamp diodes should be used for inductive

transient suppression. A VCC1 terminal, separate from VCC2, is provided for the

logic inputs to minimize device power dissipation. The L293and L293D is

characterized for operation from 0°C to 70°C.

DESCRIPTION:

The L293 and L293D are quadruple high- current half-H drives. The L293 is

designed to provide bi-directional drive current of up to 1 A at voltage from 4.5V to

36 v. The L293D is designed to provide bidirectional drive current of up to 600-mA

at voltage from 4.5V to 36V.both drives are designed to drive inductive load such as

30


relay, solenoids, dc and bipolar stepping motors, as well as other high-current/high-

voltage loads in positive- supply applications. All inputs are TTL compatible. Each

output is a complete totem drive circuit, with a Darlington transistor sink and a

pseudo-Darlington source.

Drives are enabled in pairs, with drives 1 and 2 enabled by 1,2EN and drives 3 and 4

enabled by 3,4EN.When and enable input is high, the associated drives are enabled

and their outputs are active and in phase with their inputs. When the enable input is

low, those are disabled and their outputs are off and in the high-impedance state.

With the proper date inputs, each pair of drives from a full-H (or bridge) reversible

derives suitable for solenoid or motor applications. On the L293, external high- speed

output clamp diodes should be used for inductive transient suppression. A VCC1

terminal, separate from VCC2, is provided for the logic input to minimize drives

power dissipation. The L293 and L293D are characterized for operation from 0C to

70C.

BLOCK DIAGRAM OF L293D:

FIG3.7.2: BLOCK DIAGRAM OF L293D

The basic idea is that five electrically controlled switches (transistors) are arranged to

control an output, usually a motor, using a separate input voltage. Two of the inputs,

‘ch1’ and ‘ch2’, control two switches each. If one channel is logic high and other is

logic low, then there is a voltage across the output terminals equal to the input

31


voltage. If the channels are switched then the output voltage changes the voltage

polarity.

If both channels are at the same (high or low) then the output terminals are short-

circuited. If the circuit is being used to drive a dc motor, then this setting will make

the motor stop quickly. The fifth switch is connected in series with one of the output

terminals and is controlled by the ‘enable’ (EN) input. If enable is logic high, (on)

then the switch closes and the output behave according to guidelines above. If the

enable is logic low (off) then there is open circuit (very high resistance) between the

output terminals. This state supersedes anything done with the input channels. When

using this circuit to control a DC motor, the enable low setting allows the motor to

float to a stop.

3.8: LM393:

It is called as DUAL DIFFERENTIAL COMPARATOR

DESCRIPTION:

The UTC LM393 consists of two independent voltage comparators, designed

specifically to operate from a single power supply over a wide voltage range.

FEATURES:

*Single or dual supply operation.

*Wide operating supply range (Vcc=2V~36V or +- 1 to +- 18V).

*Input common-mode voltage includes ground.

*Low supply current drain ICC=0.8mA (Typical).

*Low input bias current Ibias=25nA (Typical).

*Output compatible with TTL, DTL, and CMOS logic

32


FIG 3.8.1: PIN CONFIGURATION

SCHEMATIC DIAGRAM OF LM393:

FIG 3.8.2: SCHEMATIC DIAGRAM OF LM393

3.9: THERMISTOR:

33


Thermistors are thermal resistors. Thermistors are the negative temperature resistance

co-efficient materials that imply the resistance of the thermistor decreases when the

temperature increases. The output of the thermistor is given to the comparator-

LM393, which compares the thermistor output with the prefixed voltage signal. In

comparator there are two terminals. One is inverting terminal (-) and the other one is

non-inverting terminal (+).

Conditions for comparator:

If + > - the output will be high

If + < - the output will be low

The output of the comparator is given to the microcontroller.

Like the RTD, the thermistor is also a temperature-sensitive resistor. While the

thermocouple is the most versatile temperature transducer and the PRTD is the most

stable, the word that best describes the thermistor is sensitive. Of the three major

categories of sensors, the thermistor exhibits by far the largest parameter change with

temperature.

Thermistors are generally composed of semiconductor materials. Although positive

temperature coefficient units are available, most thermistors have a negative

34


temperature coefficient (TC); that is, their resistance decreases with increasing

temperature. The negative TC can be as large as several percent per degree C,

allowing the thermistor circuit to detect minute changes in temperature which could

not be observed with an RTD or thermocouple circuit. The price we pay for this

increased sensitivity is loss of linearity. The thermistor is an extremely non-linear

device which is highly dependent upon process parameters. Consequently,

manufacturers have not standardized thermistor curves to the extent that RTD and

thermocouple curves have been standardized. An individual thermistor curve can be

very closely approximated through use of the Steinhart-Hart equation:

1 = A + B (ln R) + C (ln R)3T

Where:

T = Kelvin’s

R = Resistance of the thermistor

A,B,C = curve-fitting constants

A, B, and C are found by selecting three data points on the published data curve and

solving the three simultaneous equations. When the data points are chosen to span no

more than 100° C within the nominal center of the thermistors temperature range, this

equation approaches a rather remarkable ±.02° C curve fit.

35


Somewhat faster computer execution time is achieved through a simpler equation:

T = (ln R)1 – A -C

where A, B, and C are again found by selecting three (R,T) data points and solving

the three resultant simultaneous equations. This equation must be applied over a

narrower temperature range in order to approach the accuracy of the Steinhart-Hart

equation. Measurement The high resistivity of the thermistor affords it a distinct

measurement advantage. The four-wire resistance measurement may not be required

as it is with RTD’s. For example, a common thermistor value is 5000W at 25° C.

With a typical TC of 4%/° C, a measurement lead resistance of 10W produces

only .05° C error. This error is a factor of 500 times less than the equivalent RTD

error.

THERMISTOR OVERVIEW:

A thermistor is a piece of semiconductor made from metal oxides, pressed into a

small bead, disk, wafer, or other shape, sintered at high temperatures, and finally

coated with epoxy or glass. The resulting device exhibits an electrical resistance that

varies with temperature.

There are two types of thermistors – negative temperature coefficient (NTC)

thermistors, whose resistance decreases with increasing temperature, and positive

temperature coefficient (PTC) thermistors, whose resistance increases with increasing

36


temperature. NTC thermistors are much more commonly used than PTC thermistors,

especially for temperature measurement applications.

A main advantage of thermistors for temperature measurement is their extremely high

sensitivity. For example, a 2252 W thermistor has a sensitivity of -100 W/°C at room

temperature. Higher resistance thermistors can exhibit temperature coefficients of -10

kW/°C or more. In comparison, 100 W platinum RTD has a sensitivity of only 0.4

W/°C. The physically small size of the thermistor bead also yields a very fast

response to temperature changes.

Another advantage of the thermistor is its relatively high resistance. Thermistors are

available with base resistances (at 25° C) ranging from hundreds to millions of ohms.

This high resistance diminishes the effect of inherent resistances in the lead wires,

which can cause significant errors with low resistance devices such as RTDs. For

example, while RTD measurements typically require 3-wire or 4-wire connections to

reduce errors caused by lead wire resistances, 2-wire connections to thermistors are

usually adequate.

The major tradeoff for the high resistance and sensitivity of the thermistor is its

highly nonlinear output and relatively limited operating range. Depending on the type

of thermistors, upper ranges are typically limited to around 300° C. Figure 1 shows

the resistance-temperature curve for a 2252 W thermistor. The curve of a 100 W RTD

is also shown for comparison.

The temperature is detected by the thermistor and the heat passes through it. The

heater is on if the temperature is in low state than the set point. The heater will be off

if the temperature reaches the set point.

NTC THERMISTORS:

The NTC thermistors which are discussed herein are composed of metal oxides. The

most commonly used oxides are those of manganese, nickel, cobalt, iron, copper and

titanium. The fabrication of commercial NTC thermistors uses basic ceramics

37


technology and continues today much as it has for decades. In the basic process, a

mixture of two or more metal oxide powders are combined with suitable binders, are

formed to a desired geometry, dried, and sintered at an elevated temperature. By

varying the types of oxides used, their relative proportions, the sintering atmosphere,

and the sintering temperature, a wide range of resistivities and temperature coefficient

characteristics can be obtained.

NTC thermistors are available in a wide variety of configurations and protective

coatings to suit almost any application. The most stable and accurate thermistors

available are those which are hermetically sealed in glass. Hermetically sealed

thermistors are also used, almost exclusively, for applications that require continuous

exposure to temperatures above 150°C.

In general, bead-type thermistors offer high stability and reliability, fast response

times, and operation at high temperatures. They are available in small sizes and,

consequently, exhibit comparatively low dissipation constants. They are more costly

to manufacture than metalized surface contact type thermistors and interchangeability

is normally achieved by using matched pairs of units connected in either series or

parallel circuits.

PROPERTIES OF NTC THERMISTORS:

NTC thermistors have thermal and electrical properties which are important

considerations in each application. These properties are a function of the geometry of

the thermistor, of the particular “material system” of metal oxides that is being used

and of the additional materials (electrodes, inks, solders, lead wires, etc.) that are

applied to the basic device. These properties and other product data are presented in

the manufacturers catalogs as nominal resistance values, resistance- vs -temperature

curves (tables), thermal time constant values, dissipation constant values and power

ratings.

38


THERMAL PROPERTIES:

When an NTC thermistor is connected in an electrical circuit, power is dissipated as

heat and the body temperature of the thermistor will rise above the ambient

temperature of its environment. The rate at which energy is supplied must equal the

rate at which energy is lost plus the rate at which energy is absorbed (the energy

storage capacity of the device).

dH/dt = dHL/dt +dHA/dt.

ELECTRICAL PROPERTIES:

There are three basic electrical characteristics that account for virtually all of the

applications in which NTC thermistors may be used.

a) Current-Time Characteristic

b) Voltage-Current Characteristic

c) Resistance-Temperature Characteristic

There are also several applications where the NTC thermistor is indirectly heated by

resistive devices or even other thermistors. These applications are merely special

cases of one of the three basic electrical characteristics.

NTC THERMISTOR APPLICATIONS:

The NTC thermistor is a versatile component that can be used in a wide variety of

applications where the measured is temperature dependent. Table gives a partial

listing of thermistor applications that are grouped according to one of the three

fundamental electrical characteristics; the current-time characteristics, the voltage-

current characteristic, and the resistance-temperature characteristic. Applications

based on the voltage-current characteristic generally involve changes in the

environmental conditions or the electrical circuit parameters of a self-heated

thermistor. In turn, these changes will result in a shift of the operating point on any

39


given voltage-current curve or family of such curves. These applications are further

subdivided into four major categories depending on the type of excitation that causes

the operating point to change.

The KE range of NTC disc thermistors is designed for use in temperature

measurement, control and compensation applications, particularly where moderate

power levels are expected to be dissipated in the thermistor.

3.10: BC 547:

TECHNICAL SPECIFICATIONS:

The BC547 transistor is an NPN Epitaxial Silicon Transistor. The BC547 transistor is

a general-purpose transistor in small plastic packages. It is used in general-purpose

switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-

purpose transistors.

FIG 3.10.1: BC 547 TRANSISTOR PINOUTS

The BC547 transistor is an NPN bipolar transistor, in which the letters "N" and "P"

refer to the majority charge carriers inside the different regions of the transistor. Most

bipolar transistors used today are NPN, because electron mobility is higher than hole

mobility in semiconductors, allowing greater currents and faster operation. NPN

transistors consist of a layer of P-doped semiconductor (the "base") between two N-

doped layers. A small current entering the base in common-emitter mode is amplified

in the collector output. In other terms, an NPN transistor is "on" when its base is

pulled high relative to the emitter. The arrow in the NPN transistor symbol is on the

emitter leg and points in the direction of the conventional current flow when the

device is in forward active mode.

One mnemonic device for identifying the symbol for the NPN transistor is "not

pointing in." An NPN transistor can be considered as two diodes with a shared anode

40


region. In typical operation, the emitter base junction is forward biased and the base

collector junction is reverse biased. In an NPN transistor, for example, when a

positive voltage is applied to the base emitter junction, the equilibrium between

thermally generated carriers and the repelling electric field of the depletion region

becomes unbalanced, allowing thermally excited electrons to inject into the base

region. These electrons wander (or "diffuse") through the base from the region of

high concentration near the emitter towards the region of low concentration near the

collector. The electrons in the base are called minority carriers because the base is

doped p-type which would make holes the majority carrier in the base.

3.11. IR PAIRS:

Basics of IR transmitter Infrared transmitter emits IR rays in planar wave front manner.Even though infra red rays spread in all directions, it propagates along straight line in forward direction. IR rays have the characteristics of producing secondary wavelets when it collides with any obstacles in its path. This property of IR is discussed here.

.

FIG 3.11.1: IR PAIRS

When IR rays gets emitted from LED, it moves in the direction it is angled. When any obstacle

interferes in the path, the IR rays get cut and it produces secondary wavelets which propagates

mostly in return direction or in a direction opposite to that of the primary waves, which

produces the net result like reflection of IR rays.

Basics of IR receiver: Infrared photo receiver is a two terminal PN junction device, which operates in a reverse bias. It has a small transparent window, which allows light to strike the

41

http://bp1.blogger.com/_1YUZv5rd5AE/SGSYLT8uieI/AAAAAAAABTQ/pr_90bkHkm8/s1600-h/ir-transmitter.JPG


PN junction. A photodiode is a type of photo detector capable of converting light into either current or voltage, depending upon the mode of operation. Most photodiodes will look similar to a light emitting diode. They will have two leads, or wires, coming from the bottom.

The shorter end of the two is the cathode, while the longer end is the anode.

INFRARED DETECTORS BASICS:

An infrared emitter is an LED made from gallium arsenide, which emits near-infrared energy

at about 880nm.

The infrared phototransistor acts as a transistor with the base voltage determined by the

amount of light hitting the transistor. Hence it acts as a variable current source. Greater

amount of IR light cause greater current to flow through the collector-emitter leads. As shown

in the diagram below, the phototransistor is wired in a similar configuration to the voltage

divider. The variable current traveling through the resistor causes a voltage drop in the pull-up

resistor.

This voltage is measured at the output of the device

3.12. LED:

A light-emitting diode (LED) is a semiconductor light source. LED’s are used as

indicator lamps in many devices, and are increasingly used for lighting. Introduced as

a practical electronic component in 1962, early LED’s emitted low-intensity red light,

42

http://irbasic.blogspot.com/2006/11/use-of-infrared-detectors-basics.html


but modern versions are available across the visible, ultraviolet and infrared

wavelengths, with very high brightness. The internal structure and parts of a led are

shown in figures 3.4.1 and 3.4.2 respectively.

Fig

3.12.1: Inside a LED Fig 3.12.2: Parts of a LED

Working:

The structure of the LED light is completely different than that of the light bulb.

Amazingly, the LED has a simple and strong structure. The light-emitting

semiconductor material is what determines the LED's colour. The LED is based on

the semiconductor diode.

When a diode is forward biased (switched on), electrons are able to recombine with

holes within the device, releasing energy in the form of photons. This effect is called

electroluminescence and the color of the light (corresponding to the energy of the

photon) is determined by the energy gap of the semiconductor. An LED is usually

small in area (less than 1 mm2), and integrated optical components are used to shape

its radiation pattern and assist in reflection. LED’s present many advantages over

incandescent light sources including lower energy consumption, longer lifetime,

improved robustness, smaller size, faster switching, and greater durability and

43


reliability. However, they are relatively expensive and require more precise current

and heat management than traditional light sources. Current LED products for general

lighting are more expensive to buy than fluorescent lamp sources of comparable

output. They also enjoy use in applications as diverse as replacements for traditional

light sources in automotive lighting (particularly indicators) and in traffic signals. The

compact size of LED’s has allowed new text and video displays and sensors to be

developed, while their high switching rates are useful in advanced communications

technology. The electrical symbol and polarities of led are shown in fig: 3.4.3.

FIG 3.12.3: ELECTRICAL SYMBOL & POLARITIES OF LED

LED lights have a variety of advantages over other light sources:

High-levels of brightness and intensity

High-efficiency

Low-voltage and current requirements

Low radiated heat

High reliability (resistant to shock and vibration)

No UV Rays

Long source life

Can be easily controlled and programmed

Applications of LED fall into three major categories:

44


Visual signal application where the light goes more or less directly from the

LED to the human eye, to convey a message or meaning.

Illumination where LED light is reflected from object to give visual response

of these objects.

Generate light for measuring and interacting with processes that do not

involve the human visual system.

3.13: Buzzer

Basically, the sound source of a piezoelectric sound component is a piezoelectric

diaphragm. A piezoelectric diaphragm consists of a piezoelectric ceramic plate which

has electrodes on both sides and a metal plate (brass or stainless steel, etc.). A

piezoelectric ceramic plate is attached to a metal plate with adhesives. Applying D.C.

voltage between electrodes of a piezoelectric diaphragm causes mechanical distortion

due to the piezoelectric effect. For a misshaped piezoelectric element, the distortion

of the piezoelectric element expands in a radial direction. And the piezoelectric

diaphragm bends toward the direction. The metal plate bonded to the piezoelectric

element does not expand. Conversely, when the piezoelectric element shrinks, the

piezoelectric diaphragm bends in the direction Thus, when AC voltage is applied

across electrodes, the bending is repeated, producing sound waves in the air.

To interface a buzzer the standard transistor interfacing circuit is used. Note that if a

different power supply is used for the buzzer, the 0V rails of each power supply must

be connected to provide a common reference.

If a battery is used as the power supply, it is worth remembering that piezo sounders

draw much less current than buzzers. Buzzers also just have one ‘tone’, whereas a

piezo sounder is able to create sounds of many different tones.

To switch on buzzer -high 1

To switch off buzzer -low 1

45


Notice (Handling) In Using Self Drive Method:

1. When the piezoelectric buzzer is set to produce intermittent sounds, sound

may be heard continuously even when the self drive circuit is turned ON /

OFF at the "X" point shown in Fig. 9. This is because of the failure of turning

off the feedback voltage.

2. Build a circuit of the piezoelectric sounder exactly as per the recommended

circuit shown in the catalog. hfe of the transistor and circuit constants are

designed to ensure stable oscillation of the piezoelectric sounder.

3. Design switching which ensures direct power switching.

4. The self drive circuit is already contained in the piezoelectric buzzer. So there

is no need to prepare another circuit to drive the piezoelectric buzzer.

5. Rated voltage (3.0 to 20Vdc) must be maintained. Products which can operate

with voltage higher than 20Vdc are also available.

6. Do not place resistors in series with the power source, as this may cause

abnormal oscillation. If a resistor is essential to adjust sound pressure, place a

capacitor (about 1μF) in parallel with the piezo buzzer.

7. Do not close the sound emitting hole on the front side of casing.

8. Carefully install the piezo buzzer so that no obstacle is placed within 15mm

from the sound release hole on the front side of the casing.

FIG 3.13.1: PICTURE OF BUZZER

CHAPTER-4

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4. SOFTWARE REQUIREMENTS

4.1: INTRODUCTION TO KEIL MICRO VISION (IDE):

Keil an ARM Company makes C compilers, macro assemblers, real-time kernels,

debuggers, simulators, integrated environments, evaluation boards, and emulators for

ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.

Keil development tools for the 8051 Microcontroller Architecture support every level

of software developer from the professional applications engineer to the student just

learning about embedded software development. When starting a new project, simply

select the microcontroller you use from the Device Database and the µVision IDE

sets all compiler, assembler, linker, and memory options for you.

Keil is a cross compiler. So first we have to understand the concept of compilers and

cross compilers. After then we shall learn how to work with keil.

4.2: CONCEPT OF COMPILER:

Compilers are programs used to convert a High Level Language to object code.

Desktop compilers produce an output object code for the underlying microprocessor,

but not for other microprocessors. I.E the programs written in one of the HLL like

‘C’ will compile the code to run on the system for a particular processor like x86

(underlying microprocessor in the computer). For example compilers for Dos

platform is different from the Compilers for Unix platform So if one wants to define

a compiler then compiler is a program that translates source code into object code.

The compiler derives its name from the way it works, looking at the entire piece of

source code and collecting and reorganizing the instruction. See there is a bit little

difference between compiler and an interpreter. Interpreter just interprets whole

program at a time while compiler analyses and execute each line of source code in

succession, without looking at the entire program.

47


The advantage of interpreters is that they can execute a program immediately.

Secondly programs produced by compilers run much faster than the same programs

executed by an interpreter. However compilers require some time before an

executable program emerges. Now as compilers translate source code into object

code, which is unique for each type of computer, many compilers are available for the

same language.

4.3: CONCEPT OF CROSS COMPILER:

A cross compiler is similar to the compilers but we write a program for the target

processor (like 8051 and its derivatives) on the host processors (like computer of

x86). It means being in one environment you are writing a code for another

environment is called cross development. And the compiler used for cross

development is called cross compiler. So the definition of cross compiler is a

compiler that runs on one computer but produces object code for a different type of

computer.

4.4: KEIL C CROSS COMPILER:

Keil is a German based Software development company. It provides several

development tools like

• IDE (Integrated Development environment)

• Project Manager

• Simulator

• Debugger

• C Cross Compiler, Cross Assembler, Locator/Linker

The Keil ARM tool kit includes three main tools, assembler, compiler and linker. An

assembler is used to assemble the ARM assembly program. A compiler is used to

compile the C source code into an object file. A linker is used to create an absolute

object module suitable for our in-circuit emulator.

48


4.5: Building an Application in µVision2:

To build (compile, assemble, and link) an application in µVision2, you must:

1. Select Project -(forexample,166\EXAMPLES\HELLO\HELLO.UV2).

2. Select Project - Rebuild all target files or Build target.µVision2 compiles,

assembles, and links the files in your project.

4.6: Creating Your Own Application in µVision2:

To create a new project in µVision2, you must:

1. Select Project - New Project.

2. Select a directory and enter the name of the project file.

3. Select Project - Select Device and select an 8051, 251, or C16x/ST10 device

from the Device Database™.

4. Create source files to add to the project.

5. Select Project - Targets, Groups, Files. Add/Files, select Source Group1, and

add the source files to the project.

6. Select Project - Options and set the tool options. Note when you select the

target device from the Device Database™ all special options are set

automatically. You typically only need to configure the memory map of your

target hardware. Default memory model settings are optimal for most

applications.

7. Select Project - Rebuild all target files or Build target.

4.7: Debugging an Application in µVision2:

To debug an application created using µVision2, you must:

1. Select Debug - Start/Stop Debug Session.

2. Use the Step toolbar buttons to single-step through your program. You may

enter G, main in the Output Window to execute to the main C function.

3. Open the Serial Window using the Serial #1 button on the toolbar.

49


Debug your program using standard options like Step, Go, Break, and so on.

4.8: Starting µVision2 and creating a Project:

µVision2 is a standard Windows application and started by clicking on the program

icon. To create a new project file select from the µVision2 menu Project – New

Project…. This opens a standard Windows dialog that asks you for the new project

file name. We suggest that you use a separate folder for each project. You can simply

use the icon Create New Folder in this dialog to get a new empty folder. Then select

this folder and enter the file name for the new project, i.e. Project1. µVision2 creates

a new project file with the name PROJECT1.UV2 which contains a default target and

file group name. You can see these names in the Project.

4.9: Window – Files:

Now use from the menu Project – Select Device for Target and select a CPU for your

project. The Select Device dialog box shows the µVision2 device data base. Just

select the microcontroller you use. We are using for our examples the Philips

80C51RD+ CPU. This selection sets necessary tool Options for the 80C51RD+

device and simplifies in this way the tool Configuration.

4.10: Building Projects and Creating a HEX Files:

Typical, the tool settings under Options – Target are all you need to start a new

application. You may translate all source files and line the application with a click on

the Build Target toolbar icon. When you build an application with syntax errors,

µVision2 will display errors and warning messages in the Output Window – Build

page. A double click on a message line opens the source file on the correct location in

a µVision2 editor window. Once you have successfully generated your application

you can start debugging.

50


After you have tested your application, it is required to create an Intel HEX file to

download the software into an EPROM programmer or simulator. µVision2 creates

HEX files with each build process when Create HEX files under Options for Target –

Output is enabled. You may start your PROM programming utility after the make

process when you specify the program under the option Run User Program #1.

4.11 CPU Simulation:

µVision2 simulates up to 16 Mbytes of memory from which areas can be mapped for

read, write, or code execution access. The µVision2 simulator traps

and reports illegal memory accesses. In addition to memory mapping, the simulator

also provides support for the integrated peripherals of the various 8051 derivatives.

The on-chip peripherals of the CPU you have selected are configured from the

Device.

4.12 Database selection:

You have made when you create your project target. Refer to page 58 for more

Information about selecting a device. You may select and display the on-chip

peripheral components using the Debug menu. You can also change the aspects of

each peripheral using the controls in the dialog boxes.

4.13 Start Debugging:

You start the debug mode of µVision2 with the Debug – Start/Stop Debug Session

Command. Depending on the Options for Target – Debug Configuration, µVision2

will load the application program and run the startup code µVision2 saves the editor

screen layout and restores the screen layout of the last debug session. If the program

execution stops, µVision2 opens an editor window with the source text or shows CPU

instructions in the disassembly window. The next executable statement is marked

with a yellow arrow. During debugging, most editor features are still available.

51


For example, you can use the find command or correct program errors. Program

source text of your application is shown in the same windows. The µVision2 debug

mode differs from the edit mode in the following aspects:

The “Debug Menu and Debug Commands” described on page 28 are

available. The additional debug windows are discussed in the following.

The project structure or tool parameters cannot be modified. All build

commands are disabled.

4.14 Disassembly Window:

The Disassembly window shows your target program as mixed source and assembly

program or just assembly code. A trace history of previously executed instructions

may be displayed with Debug – View Trace Records. To enable the trace history, set

Debug – Enable/Disable Trace Recording.

If you select the Disassembly Window as the active window all program step

commands work on CPU instruction level rather than program source lines. You can

select a text line and set or modify code breakpoints using toolbar buttons or the

context menu commands.

You may use the dialog Debug – Inline Assembly… to modify the CPU instructions.

That allows you to correct mistakes or to make temporary changes to the target

program you are debugging. Numerous example programs are included to help you

get started with the most popular embedded 8051 devices.

The Keil µVision Debugger accurately simulates on-chip peripherals (I²C, CAN,

UART, SPI, Interrupts, I/O Ports, A/D Converter, D/A Converter, and PWM

Modules) of your 8051 device. Simulation helps you understand hardware

configurations and avoids time wasted on setup problems. Additionally, with

simulation, you can write and test applications before target hardware is available.

4.15 EMBEDDED C:

52


Use of embedded processors in passenger cars, mobile phones, medical equipment,

aerospace systems and defense systems is widespread, and even everyday domestic

appliances such as dish washers, televisions, washing machines and video recorders

now include at least one such device.

Because most embedded projects have severe cost constraints, they tend to use low-

cost processors like the 8051 family of devices considered in this book. These popular

chips have very limited resources available most such devices have around 256 bytes

(not megabytes!) of RAM, and the available processor power is around 1000 times

less than that of a desktop processor. As a result, developing embedded software

presents significant new challenges, even for experienced desktop programmers. If

you have some programming experience - in C, C++ or Java - then this book and its

accompanying CD will help make your move to the embedded world as quick and

painless as possible.

CHAPTER-5

PROJECT DESCRIPTION

53


5.1: THEFT IDENTIFICATION:

Now a day’s everyone knows what type of security we need, security in

almost all the cases. But even after taking care we are still unsatisfied with the

security which we provide by ourselves. So as the technology is growing we are

implementing new ideas over security purpose. One such thing is using PIR sensor

which is used to detecting the human motion.

The project title “THEFT IDENTIFICATION” indicates itself that whenever

someone wants to theft which is present in the industry then the theft will be

automatically arrested with the help of some human detecting sensors and make the

buzzer and leds ON. If the sensor detects then automatically the buzzer will be ‘on’

for indicating that someone is inside the industry.

5. 2 AUTOMATICVEHICLE:

The aim of this project is to atomize the parking for allowing the vehicles into the

industry. Whenever a vehicle comes in front of the gate, the IR signal gets disturbed

and the microcontroller will open the gate by rotating the stepper motor. The gate will

be closed only after the car leaves the second IR pair since the microcontroller should

know whether the vehicle left the gate or not.

.

This project uses regulated 5V, 500mA power supply. Unregulated 12V DC is used

for relay. 7805 three terminal voltage regulator is used for voltage regulation. Bridge

type full wave rectifier is used to rectify the ac output of secondary of 230/12Vstep

down transformer

5.3 STREET LIGHTING USING SCHMITT TRIGGER:

54


These devices consist of two independent voltage comparators that are designed to

operate from a single power supply over a wide range of voltages. Operation from

dual supplies also is possible as long as the difference between the two supplies is 2 V

to 36 V, and VCC is at least 1.5 V more positive than the input common-mode voltage.

Current drain is independent of the supply voltage. The outputs can be connected to

other open-collector outputs to achieve wired-AND relationships. The LM393 and

LM393A are characterized for operation from 0°C to 70°C.

5.4 FIRE ALARM:

In this fire alarm circuit, a Thermistor works as the heat sensor. When temperature

increases, its resistance decreases, and vice versa. At normal temperature, the

resistance of the Thermistor (TH1) is approximately 10 kilo-ohms, which reduces to a

few ohms as the temperature increases beyond 100 C.

CHAPTER-6

CODING:

55


The program code which is dumped in the microcontroller of our project is shown below.1.THEFT IDENTIFICATION:

#include <16F72.h>

#fuses HS,NOWDT,PROTECT,brownout,put

#use delay (clock=20000000)

void main()

output_high(pin_c3);

delay_ms(500);

output_low(pin_c3);

delay_ms(500);


delay_ms(500);

output_low(pin_c3);

output_low(pin_c4); //Relay OFF (Door opened)

while(1)

if(input(pin_A0))


delay_ms(500);

output_low(pin_c3);

delay_ms(500);

output_high(pin_b0);

output_low(pin_b1);

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output_low(pin_b3);

delay_ms(1000);

output_high(pin_b3);


2.AUTOMATIC VEHICLE PARKING:

#include<REG52.h>

void T1M1Delay(void);void delay(unsigned char);

sbit SENSOR1=P1^0;sbit SENSOR2=P1^1;

sbit RED_LED=P3^0;sbit GREEN_LED=P3^1;

sbit BUZZER=P2^0;

sbit EN1=P2^7;sbit EN2=P2^2;

sbit IN1=P2^6;sbit IN2=P2^5;

sbit IN3=P2^4;sbit IN4=P2^3;

void main()

57


EN1=1;EN2=1;

RED_LED=1; //initially turn off LEDs motors GREEN_LED=1;

IN1=0;IN2=0;

IN3=0; //initially turn off gate motorsIN4=0;

while(1) unsigned char x; if(SENSOR1==1) BUZZER=0; T1M1Delay(); BUZZER=1;

IN1=1;IN2=0; //OPEN the Gate1

RED_LED=0; // Red LED is on & Green LED is off GREEN_LED=1; // create some delay for(x=0;x<10;x++) T1M1Delay();

else if(SENSOR2==1) BUZZER=0; T1M1Delay(); BUZZER=1; IN1=0; //CLOSE the Gate2 IN2=1; RED_LED=1; // Red LED is off & Green LED is on GREEN_LED=0;

58


// create some delay for(x=0;x<10;x++) T1M1Delay();

IN1=0; IN2=0; IN3=0; IN4=0;

void delay(unsigned char n)

int x,y; /* delay function */for(x=0;x<n;x++)for(y=0;y<600;y++);

// End of the program

void T1M1Delay(void) unsigned char y; for(y=0;y<=1;y++) TMOD=0x10; //timer 1, mode 1(16 bits) TL1=0xFE; // load TL1 TH1=0xA5; //load TH1 TR1=1; // turn ON T1 while(TF1==0); //wait until TF1 gets empty TR1=0; // turn off T1 TF1=0; // clear TF1 // FFFH-A5FEH=23042 //timer delay= 23042*1.0825uSec = 25ms. //20*25ms=500ms

CHAPTER-7

RESULTS ANALYSIS:

59


The project “Theft Identification” was designed such that the system is

capable of alerting the owner through buzzer remotely if thieves enter into the

industry. The project was executed successfully and reached the expected

results.

The compact parking system has been successfully designed for automating

the parking system in huge complexes, Trade centers, Multiplexes etc, and the

problems due to non availability of adequate space for parking of four

wheelers is solved out.

Ensures high security in contrast to conventional parking system, if any

disturbances occurs to the normal operation buzzer provided sounds and also

as the total status present at the administration ,he comes and directs the user

as the per the operation required.

If anyone tries to misuse the system, the administrator safeguards it ensuring

protection to the vehicle user.

CHAPTER-8

FUTURE SCOPE

60


Scope for Further Development:

Our project “THEFT IDENTIFICATION” is mainly intended capable of

alerting the owner through buzzer remotely if thieves enter into the industry.

This system has a PIR sensor which detects live human beings in its presence

and sends this information to the system (Microcontroller). As soon as micro

controller receives the signal it sends logic HIGH to buzzer and leds. Buzzer

is horned to intimate the thieves’ presence.

This project can be extended by using a GSM Modem so that the limitation of

distance is eliminated and the information is sent to predefined phone

numbers.

A speaking voice alarm could be used instead of the normal buzzer.

This system can be connected to communication devices such as modems,

cellular phones or satellite terminal to enable the remote collection of recorded

data or alarming of certain parameters.

A multi-controller system can be developed that will enable a master controller

along with its slave controllers to automate multiple security process

simultaneously.

By this implementation in the circuit, parking problem is solved an also it

prevents vehicle thefts.

CHAPTER-9

CONCLUSION:

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The project “IMPLEMENTING SECURITY IN INDUSTRIAL AUTOMATION” has been successfully completed and tested. Integrating the features of every hardware component used has developed it. Presence of every block has been reasoned out and placed carefully thus contributing to the best working of the unit.

The project was finished using very simple and easily available components making it lightweight and portable.

Integrating features of all the hardware components used have been developed in it. Presence of every module has been reasoned out and placed carefully, thus contributing to the best working of the unit.

Secondly, using highly advanced IC’s with the help of growing technology, the project has been successfully implemented. Thus the project has been successfully designed and tested.

Finally we conclude that “IMPLEMENTING SECURITY IN INDUSTRIAL AUTOMATION“ is an emerging field and there is huge scope for further research and development making the usage of sensors for excitement as well as security purposes.

CHAPTER-10

BIBLIOGRAPHY:

62


1. The ATMEGA32 Microcontroller, ATMEL, Designers data sheet.

2. Linear Integrated Circuit –Roy Chowdhary.

3. The Microcontroller Architecture, Programming Application--Kenneth

J.Ayala second edition

63

main project documentation

Documents

inductive

bipolar stepping

piezoelectric

vacuum tube

piezoelectric

watt 9v battery

automatic

digital signal