Motion Detector

Published on July 2016 | Categories: Documents | Downloads: 75 | Comments: 0 | Views: 712
of 83
Download PDF   Embed   Report

Comments

Content

CHAPTER 1 INTRODUCTION
1.) Introduction
A motion detector is a device that contains a physical mechanism or electronic sensor that quantifies motion that can be either integrated with or connected to other devices that alert the user of the presence of a moving object within the field of view.

1.1) Overview
An electronic motion detector contains a motion sensor that transforms the detection of motion into an electric signal. This can be achieved by measuring optical or acoustical changes in the field of view. A motion detector may be connected to a burglar alarm that is used to alert the home owner or security service after it detects motion. Such a detector may also trigger a red light camera. An occupancy sensor is a motion detector that is integrated with a timing device. It senses when motion has stopped for a specified time period in order to trigger a light extinguishing signal. These devices prevent illumination of unoccupied spaces like public toilets.

1.2) Electronic devices
The principal methods by which motion can be electronically identified are optical detection and acoustical detection. Infrared light or laser technology may be used for optical detection. Motion detection devices, such as motion detectors, have sensors that detect movement and send a signals to a sound device that produces an alarm or switch on an image recording device. There are motion detectors which employ cameras connected to a computer which stores and manages captured images to be viewed later or viewed over a computer network. The chief applications for such detection are (a) detection of unauthorized entry, (b) detection of cessation of occupancy of an area to extinguish lighting and (c) detection of a moving object which triggers a camera to record subsequent events. The motion detector is thus a linchpin of electronic security systems, but is also a valuable tool in preventing the illumination of unoccupied spaces.

Chapter 2 Project Description

2.) Project Description
Security systems in present world had turned out to be a mandatory system for every organization, Industries, workshops, factories, banks, offices, shops (especially -Jewellery shops) and even at home these days we find various kind of security systems based on different technologies. In other words Security Systems is 'The need of Hour '. In this security system we employed Visual Basic Language .Specifically in this we focused towards the 'IMAGE PROCESSING' modules of Visual Basic Programming. Now as we started developing the code we found the need of Interfacing Computer System with Hardware. For that we also learned Parallel Port Programming of Visual Basic. This gave us an idea to correlate our developed code of Visual Basic with Embedded System Technology. Our developed system is a MULTI COMPUTER BASED SYSTEM which uses atleast two computers connected via LAN/WAN/MAN. The whole system consists of only one system named as SERVER while other Multiple Computers are named as CLIENTS. The server system is always kept in ON condition. It is equipped with a Speaker and a Printer. Server is generally kept at HOME (manager or owner of the shop)/CONTROL ROOM (Police Station).Now the Client System is kept in area where security is to be provided. The Client System is equipped with a Webcam and a Speaker. Both of these systems are connected to each other Via LAN/WAN/MAN. The utility of this system lies generally during Night hours or holidays when there is absence of the staff members. To understand how this System works let us take an example of a jewellery shop. The Client Systems are kept at different places of the shop where the security is to be provided. And the Server System is kept at the home of the owner of the shop. Say at 3 a.m (midnight hours) a thief enters the shop. Now here this Security System comes into action.The Client System Detects change in Motion and starts capturing the Images of the thief at every interval of 2 seconds. It switches On the Alarm of the shop so as to make the Gatekeeper of the shop alert and simultaneously sends ALERT signals to the remote computer i.e. SERVER. Now

the Server System which is kept at home of Owner of the shop receives the alert signals from the Client .Server switches on the audio file as Alarm by making the owner of the shop aware of some mishap going on at his Shop. The Client System in the form of alert signal sends the exact Date, Time and the exact location of Area of Theft in the shop(say floor no., room no. etc).After receiving this information the Server System which is also equipped with a Printer takes out the print out of all these valuable information. Now with the help of this Security System we can get a series of Images of thief which are stored in Client Computer System. We also get the exact information of the date ,time and area at the time of theft itself.

2.1) Background Task and Interrupt-Service-Routines (pseudo code)
1. Let the camera take a picture 2. Download a “thumbnail” version (40 × 31) of the image into the SDK. 3. Compare the thumbnail with a previously taken one 4. If the difference is greater than a threshold { Execute an alarm function (to blink an LED i.e.) 5. Start, Pause or Stop the program based on Keypad inputs 6. Execute an alarm function, if the “watchdog countdown” reaches 0, (watchdog was not fed).

Figure 2: Keypad Encoder PINS (Source )

Figure 3: Schematic of keypad connection (Source )

2.2) Software Design

To support re-use and better maintainability of the software, the following modularization was chosen: • Main.c contains the main loop • CamDriver.c contains the camera specific functions, allowing control of the camera. • ImgProc.c contains the implementation of image comparison algorithms. • Watchdog.c contains the implementation of the timer-based software watchdog. • Serialin57.asm, Serialout57.asm, high-speed serial driver for the SDK’s internal serial port.

• Keypad.c contains keypad specific functions

CHAPTER 3 COMPONENTS
3.) Components used S.NO.
1. 2. 3. 4. 5. 6.

COMPONENTS
ULN 2003 STEPPER MOTOR D TYPE 25 PIN PARALLEL PORT WEB CAM TRANSISTOR D TYPE 25 PIN MALE TO

NO OF COMPONENTS
1 1 1 1 4 1

7. 8. 9. 10. 11. 12.

MALE CABLE TRANSFORMER DIODES ZENER DIODES RESISTANCES CAPACITOR LED

Table 1 component used

1 AS PER REQUIRED AS PER REQUIRED AS PER REQUIRED AS PER REQUIRED AS PER REQUIRED

3.1 STEPPER MOTOR
In Theory, a Stepper motor is a marvel in simplicity. It has no brushes, or contacts. Basically it's a synchronous motor with the magnetic field electronically switched to rotate the armature magnet around.

3.1.1 Definition
A stepper motor is basically an electromechanical device which converts electrical pulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates in discrete step increments when electrical command pulses are applied to it in the proper sequence. The motors rotation has several direct relationships to these applied input pulses. The sequence of the applied pulses is directly related to the direction of motor shafts rotation. The speed of the motor shafts rotation is directly related to the frequency of the input pulses and the length of rotation is directly related to the number of input pulses applied.

3.1.2 Characteristics:



Holding Torque - Steppers have very good low speed and holding torque. Steppers

are usually rated in terms of their holding force (oz/in) and can even hold a position (to a lesser degree) without power applied, using magnetic 'detent' torque. •

Open loop positioning - Perhaps the most valuable and interesting feature of a

stepper is the ability to position the shaft in fine predictable increments, without need to query the motor as to its position. Steppers can run 'open-loop' without the need for any kind of encoder to determine the shaft position. Closed loop systems- systems that feed back position information, are known as servo systems. Compared to servos, steppers are very easy to control; the position of the shaft is guaranteed as long as the torque of the motor is sufficient for the load, under all its operating conditions. •

Load Independent - The rotation speed of a stepper is independent of load, provided

it has sufficient torque to overcome slipping. The higher rpm a stepper motor is driven, the more torque it needs, so all steppers eventually poop out at some rpm and start slipping. Slipping is usually a disaster for steppers, because the position of the shaft becomes unknown. For this reason, software usually keeps the stepping rate within a maximum top rate. In applications where a known RPM is needed under a varying load, steppers can be very handy.

3.1.3 Working:
The stepper motor uses the theory of operation for magnets to make the motor shaft turn a precise distance when a pulse of electricity is provided. You learned previously that like poles of a magnet repel and unlike poles attract. Figure 1 shows a typical cross-sectional view of the rotor and stator of a stepper motor. From this diagram you can see that the stator (stationary winding) has four poles, and the rotor has six poles (three complete magnets). The rotor will require 12 pulses of electricity to move the 12 steps to make one complete revolution. Another way to say this is that the rotor will move precisely 30° for each pulse of electricity that the motor receives. The number of degrees the rotor will turn when a pulse of electricity is delivered to the motor can be calculated by dividing the number of degrees in one revolution of

the shaft (360°) by the number of poles (north and south) in the rotor. In this stepper motor 360° is divided by 12 to get 30°.

Figure 4. Diagram that shows the position of the six-pole rotor and four-pole stator of a typical stepper motor

When no power is applied to the motor, the residual magnetism in the rotor magnets will cause the rotor to detent or align one set of its magnetic poles with the magnetic poles of one of the stator magnets. This means that the rotor will have 12 possible detent positions. When the rotor is in a detent position, it will have enough magnetic force to keep the shaft from moving to the next position. This is what makes the rotor feel like it is clicking from one position to the next as you rotate the rotor by hand with no power applied. When power is applied, it is directed to only one of the stator pairs of windings, which will cause that winding pair to become a magnet. One of the coils for the pair will become the north pole, and the other will become the south pole. When this occurs, the stator coil that is the north pole will attract the closest rotor tooth that has the opposite polarity, and the stator coil that is the south pole will attract the closest rotor tooth that has the opposite polarity. When current is flowing through these poles, the rotor will now have a much stronger attraction to the stator winding, and the increased torque is called holding torque. By changing the current flow to the next stator winding, the magnetic field will be changed 90°. The rotor will only move 30° before its magnetic fields will again align with the change in the stator field. The magnetic field in the stator is continually changed as the rotor moves through the 12 steps to move a total of 360°. Figure 2 shows the position of the rotor changing as the current supplied to the stator changes.

FIGURE 5 Movement of the stepper motor rotor as current is pulsed to the stator. (a) Current is applied to the top and bottom windings, so the top winding is north, (b) Current is applied to left and right windings, so the left winding is north, (c) Current is applied to the top and bottom windings, so the bottom winding is north, (d) Current is applied to the left and right windings so the right winding is north.

In Fig. 5a you can see that when current is applied to the top and bottom stator windings, they will become a magnet with the top part of the winding being the north pole, and the bottom part of the winding being the south pole. You should notice that this will cause the rotor to move a small amount so that one of its south poles is aligned with the north stator pole (at the top), and the opposite end of the rotor pole, which is the north pole, will align with the south pole of the stator (at the bottom). A line is placed on the south-pole piece that is located at the 12 o'clock position in Fig. 5a so that you can follow its movement as current is moved from one stator winding to the next. In Fig. 5b current has been turned off to the top and bottom windings, and current is now applied to the stator windings shown at the right and left sides of the motor. When this occurs, the stator winding at the 3 o'clock position will have the polarity for the south pole of the stator magnet, and the winding at the 9 o'clock position will have the north-pole polarity. In this condition, the next rotor pole that will be able to align with the stator magnets is the next pole in the clockwise position to the previous pole. This means that the rotor will only need to

rotate 30° in the clockwise position for this set of poles to align itself so that it attracts the stator poles. In Fig. 5c you can see that the top and bottom stator windings are again energized, but this time the top winding is the south pole of the magnetic field and the bottom winding is the north pole. This change in magnetic field will cause the rotor to again move 30° in the clockwise position until its poles will align with the top and bottom stator poles. You should notice that the original rotor pole that was at the 12 o'clock position when the motor first started has now moved three steps in the clockwise position. In Fig. 5d you can see that the two side stator windings are again energized, but this time the winding at the 3 o'clock position is the north pole. This change in polarity will cause the rotor to move another 30° in the clockwise direction. You should notice that the rotor has moved four steps of 30° each, which means the rotor has moved a total of 120° from its original position. This can be verified by the position of the rotor pole that has the line on it, which is now pointing at the stator winding that is located in the 3 o'clock position.

3.1.4 Types of Stepper Motors:
Stepper Motors come in a variety of sizes, and strengths, from tiny floppy disk motors, to huge machinery steppers rated over 1000 oz in. Three basic types of stepper motors include the permanent magnet motor, the variable re-luctance motor, and the hybrid motor, which is a combination of the previous two .

3.1.5 Stepping Modes
The following are the most common drive modes. • Wave Drive (1 phase on) • Full Step Drive (2 phases on) • Half Step Drive (1 & 2 phases on) • Microstepping (Continuously varying motor currents)

For the following discussions please refer to the figure 9. In Wave Drive only one winding is energized at any given time. The stator is energized according to the sequence A -> B -> A -> B and the rotor steps from

position 8 -> 2 ->4 -> 6. For unipolar and bipolar wound motors with the same winding parameters this excitation mode would result in the same mechanical position. The disadvantage of this drive mode is that in the unipolar wound motor you are only using 25% and in the bipolar motor only 50% of the total motor winding at any given time. This means that you are not getting the maximum torque output from the motor. In Full Step Drive you are energizing two phases at any given time. The stator is energized
Figure 6 Unipolar and bipolar wound stepper motors.

according to the sequence

and the rotor

steps from position 1 ->3 ->5-> 7 . Full step mode results in the same angular movement as 1 phase on drive but the mechanical position is offset by one half of a full step. The torque output of the unipolar wound motor is lower than the bipolar motor (for motors with the same winding parameters) since the unipolar motor uses only 50% of the available winding while the bipolar motor uses the entire winding. Half Step Drive combines both wave and full step (1&2 phases on) drive modes. Every second step only one phase is energized and during the other phase on each stator. The stator is energized according to the sequence And the rotor steps from position 1 ->2 -> 3-> 4 ->5 -> 6 -> 7 -> 8. This results in angular movements that are half of those in 1- or 2-phases-on drive modes. Half stepping can reduce a phenomena referred to as resonance which can be experienced in 1or 2- phases-on drive modes. The excitation sequences for the above drive modes are summarized in Table 2. steps one

Table 2 excitation sequence for different driving modes

In Microstepping Drive the currents in the windings are continuously varying to be able to break up one full step into many smaller discrete steps. Shortcut for finding the proper wiring sequence For 5 wires – 1 is common to be plugged at positive supply and rest four to the pulses. For 6 wires – 2 are common to be plugged at positive supply and rest four to the pulses. Connect the center tap(s) to the power source (or current-Limiting resistor.) Connect the remaining 4 wires in any pattern. If it doesn't work, you only need try these 2 swaps... 1234 1243 1423 - (arbitrary first wiring order) - switch end pair - switch middle pair

You're finished when the motor turns smoothly in either direction. If the motor turns in the opposite direction from desired, reverse the wires so that ABCD would become DCBA.

3.2 PARALLEL PORT

A parallel port is a type of interface found on computers (personal and otherwise) for connecting various peripherals. It is also known as a printer port or Centronics port. The IEEE 1284 standard defines the bi-directional version of the port. A port contains a set of signal lines that the CPU sends or receives data with other components. We use ports to communicate via modem, printer, keyboard, mouse etc. In signaling, open signals are "1" and close signals are "0" so it is like binary system. A parallel

Fig7 parallel port

port sends 8 bits and receives 5 bits at a time. The serial port RS-232 sends only 1 bit at a time but it is multidirectional so it can send 1 bit and receive 1 bit at a time...

FIGURE8 PARALLEL PORT

3.2.1 Parallel Port - Data Ports:
In sending the sequences, you will need the data ports which can be seen in the picture from D0 to D7 .

3.2.2 Parallel Port - Status Ports:
These ports are made for reading signals. The range is like in data ports which are S0-S7. But S0, S1, S2 are invisible in the connector. And S0 is different; this bit is for timeout flag in EPP (Enhanced Parallel Port) compatible ports. The address of this status port is 0x379 . This will always be refer to "DATA+1" and it can send 5 numeric data from the 10 - 11 12 - 13 - 15 th pins. So how can we reach the data ports? It is simple: every parallel port has an address. In Windows 2000, you can see yours by Settings > Control Panel > System > Hardware > Device Manager > Ports (COM & LPT) > Printer Port(LPT1) > Properties = in Resources > Resource Setting and you can see your address for your parallel port. For Ex: Generally it is 0378-037F. This is hexadecimal like in math (mod 16). 0x378 belongs to 888 in decimal form. In this way you can look for your com port or game port addresses. Let's enlighten these bits with a printer example:

• • • • • • • •

S0: This bit becomes higher (1) if a timeout operation occurs in EPP mode. S1: Not used (Maybe for decoration :)) S2: Mostly not used but sometime this bit shows the cut condition (PIRQ) of the port S3: If the printer determines an error it becomes lower (0). Which is called nError or nFault S4: It is high (1) when the data inputs are active. Which is called Select S5: It is high(1) when there is no paper in printer. Which is called PaperEnd, PaperEmpty or PError S6: It sends low impact signaling when the printer gets a one byte data. Which is called nAck or nAcknowledge S7: This is the only reversed pin on the connector (see my table in the article) . If the printer is busy and it cannot get any additional data this pin becomes lower. Which is called Busy

3.2.3 Parallel Port - Control Ports:
This port usually used for outputting but these can be used for inputting. The range is like in data ports C0-C7 but C4, C5, C6, C7 are invisible in connector. And the address for this is 0x37A • • • • • • • • C0: This pin is reversed. It sends a command to read D0-D7 on the port. When the computer starts it is high in the connector. Which is called nStrobe C1: This pin is reversed. It sends a command to the printer to feed the next line. It is high in the connector after the machine starts. Which is called Auto LF C2: This pin is for reset the printer and clear the buffer. Which is called nInit, nInitialize C3: This pin is reversed. Sends a high(1) for opening data inputs. It is low after the machine starts. Which is called nSelectIn C4: Opens the cut operation for the printer. Not visible in the connector... C5: Sets the direction control in multidirectional ports. Not visible in the connector... C6: Not used and also Not visible in the connector... C7: Mostly not used but it is used as a C5 in some ports. Not visible in the connector...

3.2.4 Parallel Port -Ground Pins:
These are (G0 - G7) the pins from 18 to 25 . These are mostly used for completing the circuit. Different pins are required when using all the pins including the inputs.

After these we will be using data ports in experiment because there are reversed pins in control and status ports. Here is an explanation for reversed pins: While you are not sending any signals to the data port it is in closed position like "00000000" so the 8 pins have no voltage on it (0 Volt) .If you send decimal "255" (binary "11111111") every pin (D0-D7) has a +5 Volt... On the other hand, if we use control ports, there are reversed pins which are C0, C1 and C3 so while we send nothing to the control port its behaviour is "0100" in binary (decimal "11")... Signal -Strobe +Data Bit 0 +Data Bit 1 +Data Bit 2 +Data Bit 3 +Data Bit 4 +Data Bit 5 +Data Bit 6 +Data Bit 7 -Acknowledge +Busy +Paper End +Select In -Auto Feed -Error -Initialize -Select Ground BIT ¬C0 D0 D1 D2 D3 D4 D5 D6 D7 S6 ¬S7 S5 S4 ¬C1 S3 C2 ¬C3 PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1825 Direction Output Output Output Output Output Output Output Output Output Input Input Input Input Output Input Output Output Ground

Table 3 pins of parallel port

3.2.5 History
The Centronics Model 101 printer was introduced in 1970 and included the first parallel interface for printers.[1] The interface was developed by Dr. An Wang, Robert Howard and Prentice Robinson at Wang Laboratories. The now-familiar connector was selected because Wang had a surplus stock of 20,000 Amphenol 36-pin micro ribbon connectors that were originally used for one of their early calculators. The Centronics parallel interface quickly became a de facto industry standard; manufacturers of the time tended to use various connectors on the system side, so a variety of cables were required. For example, early VAX systems used a

DC-37 connector, NCR used the 36-pin micro ribbon connector, Texas Instruments used a 25pin card edge connector and Data General used a 50-pin micro ribbon connector. Dataproducts introduced a very different implementation of the parallel interface for their printers. It used a DC-37 connector on the host side and a 50 pin connector on the printer side— either a DD-50 (sometimes incorrectly referred to as a "DB50") or the block shaped M-50 connector; the M-50 was also referred to as Winchester.[2][3] Dataproducts parallel was available in a short-line for connections up to 50 feet (15 m) and a long-line version for connections from 50 feet (15 m) to 500 feet (150 m). The Dataproducts interface was found on many mainframe systems up through the 1990s, and many printer manufacturers offered the Dataproducts interface as an option. IBM released the IBM Personal Computer in 1981 and included a variant of the Centronics interface— only IBM logo printers (rebranded from Epson) could be used with the IBM PC.[4] IBM standardized the parallel cable with a DB25F connector on the PC side and the Centronics connector on the printer side. Vendors soon released printers compatible with both standard Centronics and the IBM implementation. IBM implemented an early form of bidirectional interface in 1987. HP introduced their version of bidirectional, known as Bitronics, on the LaserJet 4 in 1992. The Bitronics and Centronics interfaces were superseded by the IEEE 1284 standard in 1994.

3.2.6 Uses
Before the advent of USB, the parallel interface was adapted to access a number of peripheral devices other than printers. Probably one of the earliest devices to use parallel were dongles used as a hardware key form of software copy protection. Zip drives and scanners were early implementations followed by external modems, sound cards, webcams, gamepads, joysticks and external hard disk drives and CD-ROM drives. Adapters were available to run SCSI devices via parallel. Other devices such as EPROM programmers and hardware controllers could be connected parallel.

3.2.7 Current use
At the consumer level, the USB interface—and in some cases Ethernet—has effectively replaced the parallel printer port. Many manufacturers of personal computers and laptops consider parallel to be a legacy port and no longer include the parallel interface. USB to

parallel adapters are available to use parallel-only printers with USB-only systems. However, due to the simplicity of its implementation, it is often used for interfacing with custom-made peripherals.

3.3 ULN 2003

The ULN2001, ULN2002, ULN2003 and ULN 2004 are high voltage, high current Darlington Arrays each are containing seven open collector Darlington pairs with common emitters. Each Channel rated at 500 mA and can withstand peak currents of 600 mA. Suppression diodes are Included for inductive load driving and the inputs are pinned opposite the outputs to simplify board layout. The versions interface to all common logic families: – ULN2001 (general purpose, DTL, TTL, PMOS, CMOS) – ULN2002 (14-25V PMOS) – ULN2003 (5V TTL, CMOS) – ULN2004 (6-15V CMOS, PMOS)

These versatile devices are useful for driving a wide range of loads including solenoids, relays DC motors; LED displays filament lamps, thermal print heads and high power buffers. The ULN2001A/2002A/2003A and 2004A are supplied in 16 pin plastic DIP packages with a

Copper lead frame to reduce thermal resistance. They are available also in small outline package SO-16) as ULN2001D1/2002D1/2003D1/ 2004D1.

3.3.1 Features
■ Seven darlingtons per package ■ Output current 500 mA per driver (600 Ma peak) ■ Output voltage 50 V ■ Integrated suppression diodes for inductive loads ■ Outputs can be paralleled for higher current ■ TTL/CMOS/PMOS/DTL Compatible inputs ■ Inputs pinned opposite outputs to simplify ayout

3.3.2 Pin configurations

Figure 9. Pin connections (top

view)

3.3.3 Maximum ratings
Symbo l Output VO voltage V
I

Parameter

Value 50 30 500 25 - 20 to 85 - 55 to 150 150

Unit V V mA mA °C °C °C

I
C

I
B

T
A

Input voltage (for ULN2002A/D 2003A/D - 2004A/D) Continuous collector current Continuous base current Operating ambient temperature range Storage temperature range Junction temperature

T
S T G

T
J

Table 4. ABSOLUTE MAXIMUM RATING

3.4 capacitor
A capacitor or condenser is a passive electronic component consisting of a pair of conductors separated by a dielectric. When a voltage potential difference exists between the conductors, an electric field is present in the dielectric. This field stores energy and produces a mechanical force between the plates. The effect is greatest between wide, flat, parallel, narrowly separated conductors.

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. The properties of capacitors in a circuit may determine the resonant frequency and quality factor of a resonant circuit, power dissipation and operating frequency in a digital logic circuit, energy capacity in a high-power system, and many other important system characteristics.

3.4.1 Theory of operation
A capacitor consists of two conductors separated by a non-conductive region. The nonconductive 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.

3.4.2 Energy storage
Work must be done by an external influence to move charge between the conductors in a capacitor. When the external influence is removed, the charge separation persists and energy is stored in the electric field. If charge is later allowed to return to its equilibrium position, the

energy is released. The work done in establishing the electric field, and hence the amount of energy stored, is given by:

3.4.3 Current-voltage relation
The current i (t ) through a component in an electric circuit is defined as the rate of change of the charge q (t ) that has passed through it. Physical charges cannot pass through the dielectric layer of a capacitor, but rather build up in equal and opposite quantities on the electrodes: as each electron accumulates on the negative plate, one leaves the positive plate. Thus the accumulated charge on the electrodes is equal to the integral of the current, as well as being proportional to the voltage (as discussed above). As with any antiderivative, a constant of integration is added to represent the initial voltage v (t0). This is the integral form of the capacitor equation,

. Taking the derivative of this, and multiplying by C, yields the derivative form,[9]

. The dual of the capacitor is the inductor, which stores energy in the magnetic field rather than the electric field. Its current-voltage relation is obtained by exchanging current and voltage in the capacitor equations and replacing C with the inductance L.

3.4.4 DC circuits

A simple resistor-capacitor circuit demonstrates charging of a capacitor.

A series circuit containing only a resistor, a capacitor, a switch and a constant DC source of voltage V0 is known as a charging circuit.[10] If the capacitor is initially uncharged while the switch is open, and the switch is closed at t = 0, it follows from Kirchhoff's voltage law that

Taking the derivative and multiplying by C, gives a first-order differential equation,

At t = 0, the voltage across the capacitor is zero and the voltage across the resistor is V0. The initial current is then i (0) =V0 /R. With this assumption, the differential equation yields

where τ0 = RC is the time constant of the system. As the capacitor reaches equilibrium with the source voltage, the voltage across the resistor and the current through the entire circuit decay exponentially. The case of discharging a charged capacitor likewise demonstrates exponential decay, but with the initial capacitor voltage replacing V0 and the final voltage being zero.

AC circuits
See also: reactance (electronics) and electrical impedance#Deriving the device specific impedances Impedance, the complex sum of reactance and resistance, describes the phase difference and the ratio of amplitudes between sinusoidally varying voltage and sinusoidally varying current at a given frequency. Fourier analysis allows any signal to be constructed from a spectrum of frequencies, whence the circuit's reaction to the various frequencies may be found. The reactance and impedance of a capacitor are respectively

where j is the imaginary unit and ω is the angular velocity of the sinusoidal signal. The - j phase indicates that the AC voltage V = Z I lags the AC current by 90°: the positive current phase corresponds to increasing voltage as the capacitor charges, zero current corresponds to instantaneous constant voltage, etc. Note that impedance decreases with increasing capacitance and increasing frequency. This implies that a higher-frequency signal or a larger capacitor results in a lower voltage amplitude per current amplitude—an AC "short circuit" or AC coupling. Conversely, for very low frequencies, the reactance will be high, so that a capacitor is nearly an open circuit in AC analysis—those frequencies have been "filtered out." Capacitors are different from resistors and inductors in that the impedance is inversely proportional to the defining characteristic, i.e. capacitance.

3.4.5 Parallel plate model

FIG10 PARALLEL PLATE CAPACIOTOR

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. 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.

3.4.6 Networks

Several capacitors in parallel. Main article: Series and parallel circuits Capacitors in a parallel configuration each have the same applied voltage. Their capacitances add up. Charge is apportioned among them by size. Using the schematic diagram to visualize parallel plates, it is apparent that each capacitor contributes to the total surface area.

Several capacitors in series. Connected in series, the schematic diagram reveals that the separation distance, not the plate area, adds up. The capacitors each store instantaneous charge build-up equal to that of every other capacitor in the series. The total voltage difference from end to end is apportioned to each capacitor according to the inverse of its capacitance. The entire series acts as a capacitor smaller than any of its components.

Capacitors are combined in series to achieve a higher working voltage, for example for smoothing a high voltage power supply. The voltage ratings, which are based on plate separation, add up. In such an application, several series connections may in turn be connected in parallel, forming a matrix. The goal is to maximize the energy storage utility of each capacitor without overloading it. Series connection is also used to adapt electrolytic capacitors for AC use.

3.5 Resistor
A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current 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 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 depends upon the materials constituting the resistor as well as its physical dimensions; it's determined by design. 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.

3.5.1 Theory of operation
Ohm's law
The behavior of an ideal resistor is dictated by the relationship specified in Ohm's law: V = IR 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 each have the same potential difference (voltage). To find their total equivalent resistance (Req):

The parallel property can be represented in equations by two vertical lines "||" (as in geometry) to simplify equations. For two resistors,

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:

A resistor network that is a combination of parallel and series can sometimes be broken up into smaller parts that are either one or the other. For instance,

However, many resistor networks cannot be split up in this way. Consider a cube, each edge of which has been replaced by a resistor. For example, determining the resistance between two

opposite vertices requires matrix methods for the general case. However, if all twelve resistors are equal, the corner-to-corner resistance is 5⁄6 of any one of them. The practical application to resistors is that a resistance of any non-standard value can be obtained by connecting standard values in series or in parallel.

3.5.2 Power dissipation
The power dissipated by a resistor is the voltage across the resistor multiplied by the current through the resistor:

All three equations are equivalent. The first is derived from Joule's law, and Ohm’s Law derives the other two from that. The total amount of heat energy released is the integral of the power over time:

If the average power dissipated is more than the resistor can safely dissipate, the resistor may depart from its nominal resistance, and may be damaged by overheating. Excessive power dissipation may raise the temperature of the resistor to a point where it burns out, which could cause a fire in adjacent components and materials. There are flameproof resistors that fail (open circuit) before they overheat dangerously. Note that the nominal power rating of a resistor is not the same as the power that it can safely dissipate in practical use. Air circulation and proximity to a circuit board, ambient temperature, and other factors can reduce acceptable dissipation significantly. Rated power dissipation may be given for an ambient temperature of 25°C in free air. Inside an equipment case at 60°C, rated dissipation will be significantly less; if we are dissipating a bit less than the maximum figure given by the manufacturer we may still be outside the safe operating area, and courting premature failure.

3.5.3 Construction
Lead arrangements

Through-hole components typically have leads leaving the body axially. Others have leads coming off their body radially instead of parallel to the resistor axis. Other components may be SMT (surface mount technology) while high power resistors may have one of their leads designed into the heatsink.

Carbon composition
Carbon composition resistors consist of a solid cylindrical resistive element with embedded wire leads or metal end caps to which the lead wires are attached. The body of the resistor is protected with paint or plastic. Early 20th-century carbon composition resistors had uninsulated bodies; the lead wires were wrapped around the ends of the resistance element rod and soldered. The completed resistor was painted for color coding of its value. The resistive element is made from a mixture of finely ground (powdered) carbon and an insulating material (usually ceramic). A resin holds the mixture together. The resistance is determined by the ratio of the fill material (the powdered ceramic) to the carbon. Higher concentrations of carbon, a weak conductor, result in lower resistance. Carbon composition resistors were commonly used in the 1960s and earlier, but are not so popular for general use now as other types have better specifications, such as tolerance, voltage dependence, and stress (carbon composition resistors will change value when stressed with over-voltages). Moreover, if internal moisture content (from exposure for some length of time to a humid environment) is significant, soldering heat will create a non-reversible change in resistance value. These resistors, however, if never subjected to overvoltage nor overheating were remarkably reliable. They are still available, but comparatively quite costly. Values ranged from fractions of an ohm to 22 megohms.

Carbon film
A carbon film is deposited on an insulating substrate, and a helix cut in it to create a long, narrow resistive path. Varying shapes, coupled with the resistivity of carbon, (ranging from 9 to 40 µΩcm) can provide a variety of resistances.[1] Carbon film resistors feature a power rating range of 1/6 W to 5 W at 70°C. Resistances available range from 1 ohm to 10 megohm. The carbon film resistor can operate between temperatures of -55°C to 155°C. It has 200 to 600 volts maximum working voltage range.

Thick and thin film

Thick film resistors became popular during the 1970s, and most SMD (surface mount device) resistors today are of this type. The principal difference between thin film and thick film resistors is not the actual thickness of the film, but rather how the film is applied to the cylinder (axial resistors) or the surface (SMD resistors). Thin film resistors are made by sputtering (a method of vacuum deposition) the resistive material onto an insulating substrate. The film is then etched in a similar manner to the old (subtractive) process for making printed circuit boards; that is, the surface is coated with a photo-sensitive material, then covered by a pattern film, irradiated with ultraviolet light, and then the exposed photo-sensitive coating is developed, and underlying thin film is etched away. Because the time during which the sputtering is performed can be controlled, the thickness of the thin film can be accurately controlled. The type of material is also usually different consisting of one or more ceramic (cermet) conductors such as tantalum nitride (TaN), ruthenium dioxide (RuO2), lead oxide (PbO), bismuth ruthenate (Bi2Ru2O7), nickel chromium (NiCr), and/or bismuth iridate (Bi2Ir2O7). The resistance of both thin and thick film resistors after manufacture is not highly accurate; they are usually trimmed to an accurate value by abrasive or laser trimming. Thin film resistors are usually specified with tolerances of 0.1, 0.2, 0.5, or 1%, and with temperature coefficients of 5 to 25 ppm/K. Thick film resistors may use the same conductive ceramics, but they are mixed with sintered (powdered) glass and some kind of liquid so that the composite can be screen-printed. This composite of glass and conductive ceramic (cermet) material is then fused (baked) in an oven at about 850 °C. Thick film resistors, when first manufactured, had tolerances of 5%, but standard tolerances have improved to 2% or 1% in the last few decades. Temperature coefficients of thick film resistors are high, typically ±200 or ±250 ppm/K; a 40 kelvin (70°F) temperature change can change the resistance by 1%. Thin film resistors are usually far more expensive than thick film resistors, although, for example, SMD thin film resistors, with 0.5% tolerances, and with 25 ppm/K temperature coefficients, when bought in full size reel quantities, are about twice the cost of 1%, 250 ppm/K thick film resistors.

Metal film
A common type of axial resistor today is referred to as a metal-film resistor. MELF (Metal Electrode Leadless Face) resistors often use the same technology, but are a cylindrically shaped resistor designed for surface mounting. [Note that other types of resistors, e.g. carbon composition, are also available in "MELF" packages]. Metal film resistors are usually coated with nickel chromium (NiCr), but might be coated with any of the cermet materials listed above for thin film resistors. Unlike thin film resistors, the material may be applied using different techniques than sputtering (though that is one such technique). Also, unlike thin-film resistors, the resistance value is determined by cutting a helix through the coating rather than by etching. [This is similar to the way carbon resistors are made.] The result is a reasonable tolerance (0.5, 1, or 2%) and a temperature coefficient of (usually) 25 or 50 ppm/K.

Resistance standards
Resistors of extremely high precision are manufactured as substandards of resistance for calibration and laboratory use. They may have 4 terminals, using one pair to carry an operating current, and the other pair to measure the voltage drop; this minimizes temperature coefficients and thermal EMFs.

3.5.4 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 all 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. 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 560,000Ω at ±2% tolerance accuracy. 560,000Ω changes to 560 kΩ ±2% (as a kilo- is 103). Each color corresponds to a certain digit, progressing from darker to lighter colors, as shown in the chart below. Color Black Brown Red Orange Yellow Green Blue Violet Gray White Gold Silver 1st band 0 1 2 3 4 5 6 7 8 9 2nd band 0 1 2 3 4 5 6 7 8 9 3rd band (multiplier) ×100 ×101 ×102 ×103 ×104 ×105 ×106 ×107 ×108 ×109 ×10-1 ×10-2 4th band (tolerance) Temp. Coefficient ±1% (F) ±2% (G) 100 ppm 50 ppm 15 ppm 25 ppm

±0.5% (D) ±0.25% (C) ±0.1% (B) ±0.05% (A) ±5% (J) ±10% (K)

5 TABLE Diffren Color of resistor t

Preferred values
Early resistors were made in more or less arbitrary round numbers; a series might have 100, 125, 150, 200, 300, etc. Resistors as manufactured are subject to a certain percentage tolerance, and it makes sense to manufacture values that correlate with the tolerance, so that the actual value of a resistor overlaps slightly with its neighbors. Wider spacing leaves gaps; narrower spacing

increases manufacturing and inventory costs to provide resistors that are more or less interchangeable. A logical scheme is to produce resistors in a range of values which increase in a geometrical progression, so that each value is greater than its predecessor by a fixed multiplier or percentage, chosen to match the tolerance of the range. For example, for a tolerance of ±20% it makes sense to have each resistor about 1.5 times its predecessor, covering a decade in 6 values. In practice the factor used is 1.4678, giving values of 1.47, 2.15, 3.16, 4.64, 6.81, 10 for the 1-10 decade (a decade is a range increasing by a factor of 10; 0.1-1 and 10-100 are other examples); these are rounded in practice to 1.5, 2.2, 3.3, 4.7, 6.8, 10; followed, of course by 15, 22, 33, … and preceded by … 0.47, 0.68, 1. This scheme has been adopted as the E6 range of the IEC 60063 preferred number series. There are also E12, E24, E48, E96 and E192 ranges for components of ever tighter tolerance, with 12, 24, 96, and 192 different values within each decade. The actual values used are in the IEC 60063 lists of preferred numbers. A resistor of 100 ohms ±20% would be expected to have a value between 80 and 120 ohms; its E6 neighbors are 68 (54-82) and 150 (120-180) ohms. A sensible spacing, E6 is used for ±20% components; E12 for ±10%; E24 for ±5%; E48 for ±2%, E96 for ±1%; E192 for ±0.5% or better. Resistors are manufactured in values from a few milliohms to about a gigaohm in IEC60063 ranges appropriate for their tolerance. Earlier power wirewound resistors, such as brown vitreous-enameled types, however, were made with a different system of preferred values, such as some of those mentioned in the first sentence of this section.

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.

3.6 Diode
In electronics, a diode is a two-terminal device (thermionic diodes may also have one or two ancillary terminals for a heater). Diodes have two active electrodes between which the signal of interest may flow, and most are used for their unidirectional electric current property. The varicap diode is used as an electrically adjustable capacitor. The unidirectionality most diodes exhibit is sometimes generically called the rectifying property. The most common function of a diode is to allow an electric current in one direction (called the forward biased condition) and to block the current in the opposite direction (the reverse biased condition). Thus, the diode can be thought of as an electronic version of a check valve. Real diodes do not display such a perfect on-off directionality but have a more complex nonlinear electrical characteristic, which depends on the particular type of diode technology. Diodes also have many other functions in which they are not designed to operate in this on-off manner. Early diodes included “cat’s whisker” crystals and vacuum tube devices (also called thermionic valves). Today the most common diodes are made from semiconductor materials such as silicon or germanium.

3.6.1 Semiconductor diodes

Most diodes today are based on semiconductor p-n junctions. In a p-n diode, conventional current is from the p-type side (the anode) to the n-type side (the cathode), but not in the opposite direction. Another type of semiconductor diode, the Schottky diode, is formed from the contact between a metal and a semiconductor rather than by a p-n junction.

3.6.2 Current–voltage characteristic
A semiconductor diode's current–voltage characteristic, or I–V curve, is related to the transport of carriers through the so-called depletion layer or depletion region that exists at the p-n junction between differing semiconductors. When a p-n junction is first created, conduction band (mobile) electrons from the N-doped region diffuse into the P-doped region where there is a large population of holes (places for electrons in which no electron is present) with which the electrons "recombine". When a mobile electron recombines with a hole, both hole and electron vanish, leaving behind an immobile positively charged donor (the dopant) on the N-side and negatively charged acceptor (the dopant) on the P-side. The region around the p-n junction becomes depleted of charge carriers and thus behaves as an insulator. However, the width of the depletion region (called the depletion width) cannot grow without limit. For each electron-hole pair that recombines, a positively-charged dopant ion is left behind in the N-doped region, and a negatively charged dopant ion is left behind in the P-doped region. As recombination proceeds and more ions are created, an increasing electric field develops through the depletion zone which acts to slow and then finally stop recombination. At this point, there is a "built-in" potential across the depletion zone. If an external voltage is placed across the diode with the same polarity as the built-in potential, the depletion zone continues to act as an insulator, preventing any significant electric current flow (unless electron/hole pairs are actively being created in the junction by, for instance, light. see photodiode). This is the reverse bias phenomenon. However, if the polarity of the external voltage opposes the built-in potential, recombination can once again proceed, resulting in substantial electric current through the p-n junction (i.e. substantial numbers of electrons and holes recombine at the junction).. For silicon diodes, the built-in potential is approximately 0.6 V. Thus, if an external current is passed through the diode, about 0.6 V will be developed across the diode such that the P-doped region is positive with respect to the N-doped region and the diode is said to be "turned on" as it has a forward bias.

Figure 11: I–V characteristics of a P-N junction diode (not to scale).

A diode’s I–V characteristic can be approximated by four regions of operation (see the figure at right). At very large reverse bias, beyond the peak inverse voltage or PIV, a process called reverse breakdown occurs which causes a large increase in current (i.e. a large number of electrons and holes are created at, and move away from the pn junction) that usually damages the device permanently. The avalanche diode is deliberately designed for use in the avalanche region. In the zener diode, the concept of PIV is not applicable. A zener diode contains a heavily doped p-n junction allowing electrons to tunnel from the valence band of the p-type material to the conduction band of the n-type material, such that the reverse voltage is "clamped" to a known value (called the zener voltage), and avalanche does not occur. Both devices, however, do have a limit to the maximum current and power in the clamped reverse voltage region. Also, following the end of forward conduction in any diode, there is reverse current for a short time. The device does not attain its full blocking capability until the reverse current ceases. The second region, at reverse biases more positive than the PIV, has only a very small reverse saturation current. In the reverse bias region for a normal P-N rectifier diode, the current through the device is very low (in the µA range). The third region is forward but small bias, where only a small forward current is conducted. As the potential difference is increased above an arbitrarily defined "cut-in voltage" or "onvoltage" or "diode forward voltage drop (Vd)", the diode current becomes appreciable (the level

of current considered "appreciable" and the value of cut-in voltage depends on the application), and the diode presents a very low resistance. The current–voltage curve is exponential. In a normal silicon diode at rated currents, the arbitrary "cut-in" voltage is defined as 0.6 to 0.7 volts. The value is different for other diode types — Schottky diodes can be as low as 0.2 V and red light-emitting diodes (LEDs) can be 1.4 V or more and blue LEDs can be up to 4.0 V. At higher currents the forward voltage drop of the diode increases. A drop of 1 V to 1.5 V is typical at full rated current for power diodes.

3.6.3 Shockley diode equation
The Shockley ideal diode equation or the diode law (named after transistor co-inventor William Bradford Shockley, not to be confused with tetrode inventor Walter H. Schottky) is the I–V characteristic of an ideal diode in either forward or reverse bias (or no bias). The equation is:

where I is the diode current, IS is the reverse bias saturation current, VD is the voltage across the diode, VT is the thermal voltage, and n is the emission coefficient, also known as the ideality factor. The emission coefficient n varies from about 1 to 2 depending on the fabrication process and semiconductor material and in many cases is assumed to be approximately equal to 1 (thus the notation n is omitted). The thermal voltage VT is approximately 25.85 mV at 300 K, a temperature close to “room temperature” commonly used in device simulation software. At any temperature it is a known constant defined by:

where q is the magnitude of charge on an electron (the elementary charge),

k is Boltzmann’s constant, T is the absolute temperature of the p-n junction in kelvins The Shockley ideal diode equation or the diode law is derived with the assumption that the only processes giving rise to current in the diode are drift (due to electrical field), diffusion, and thermal recombination-generation. It also assumes that the recombination-generation (R-G) current in the depletion region is insignificant. This means that the Shockley equation doesn’t account for the processes involved in reverse breakdown and photon-assisted R-G. Additionally, it doesn’t describe the “leveling off” of the I–V curve at high forward bias due to internal resistance. Under reverse bias voltages (see Figure 5) the exponential in the diode equation is negligible, and the current is a constant (negative) reverse current value of -IS. The reverse breakdown region is not modeled by the Shockley diode equation. For even rather small forward bias voltages (see Figure 5) the exponential is very large because the thermal voltage is very small, so the subtracted ‘1’ in the diode equation is negligible and the forward diode current is often approximated as

The use of the diode equation in circuit problems is illustrated in the article on diode modeling.

3.7Transistor
n electronics, a transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much larger than the controlling (input) power, the transistor provides amplification of a signal. The transistor is the fundamental building block of modern electronic devices, and is used in radio, telephone, computer and other electronic systems. Some transistors are packaged individually but most are found in integrated circuits.

3.7.1 Usage

The bipolar junction transistor, or BJT, was the first transistor invented, and through the 1970s, was the most commonly used transistor. Even after MOSFETs became available, the BJT remained the transistor of choice for many analog circuits such as simple amplifiers because of their greater linearity and ease of manufacture. Desirable properties of MOSFETs, such as their utility in low-power devices, usually in the CMOS configuration, allowed them to capture nearly all market share for digital circuits; more recently MOSFETs have captured most analog and power applications as well, including modern clocked analog circuits, voltage regulators, amplifiers, power transmitters, motor drivers, etc.

Fig 12 BJT used as an electronic switch, in grounded-emitter configuration.

3.7.2 Simplified operation

Fig 13 Amplifier circuit, standard common-emitter configuration.

Fig 14 Simple circuit using a transistor.

Fig 15 Operation graph of a transistor

The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal, that is, can act as an amplifier. Or, the transistor can be used to turn current on or off in a circuit like an electrically controlled switch, where the amount of current is determined by other circuit elements. The two types of transistors have slight differences in how they are used in a circuit. A bipolar transistor has terminals labelled base, collector and emitter. A small current at base terminal (that is, flowing from the base to the emitter) can control or switch a much larger current between collector and emitter terminals. For a field-effect transistor, the terminals are labelled gate, source, and drain, and a voltage at the gate can control a current between source and drain. The image to the right represents a typical bipolar transistor in a circuit. Charge will flow between emitter and collector terminals depending on the current in the base. Since internally the

base and emitter connections behave like a semiconductor diode, a voltage drop develops between base and emitter while the base current exists. The size of this voltage depends on the material the transistor is made from, and is referred to as VBE.

3.7.3 Transistor as a switch
Transistors are commonly used as electronic switches, for both high power applications including switched-mode power supplies and low power applications such as logic gates. It can be seen from the graph that once the base voltage reaches a certain level, shown at point B, the current will no longer increase with increasing VBE and the output will be held at a fixed voltage.[dubious – discuss] The transistor is then said to be saturated. Hence, values of input voltage can be chosen such that the output is either completely off,[9] or completely on. The transistor is acting as a switch, and this type of operation is common in digital circuits where only "on" and "off" values are relevant.

3.7.4 Transistor as an amplifier
The above common emitter amplifier is designed so that a small change in voltage in (Vin) changes the small current through the base of the transistor and the transistor's current amplification combined with the properties of the circuit mean that small swings in Vin produce large changes in Vout. It is important that the operating parameters of the transistor are chosen and the circuit designed such that as far as possible the transistor operates within a linear portion of the graph, such as that shown between A and B, otherwise the output signal will suffer distortion. Various configurations of single transistor amplifier are possible, with some providing current gain, some voltage gain, and some both. From mobile phones to televisions, vast numbers of products include amplifiers for sound reproduction, radio transmission, and signal processing. The first discrete transistor audio amplifiers barely supplied a few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved. Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive.

Some musical instrument amplifier manufacturers mix transistors and vacuum tubes in the same circuit, as some believe tubes have a distinctive sound.

3.7.5 Construction
Semiconductor material
The first BJTs were made from germanium (Ge). Silicon (Si) types currently predominate but certain advanced microwave and high performance versions now employ the compound semiconductor material gallium arsenide (GaAs) and the semiconductor alloy silicon germanium (SiGe). Single element semiconductor material (Ge and Si) is described as elemental. Rough parameters for the most common semiconductor materials used to make transistors are given in the table below; it must be noted that these parameters will vary with increase in temperature, electric field, impurity level, strain and various other factors:

Semiconductor material

Junction forward voltage V @ 25 °C 0.27 0.71 1.03

Electron mobility Hole mobility

Max. junction temp.

m²/(V·s) @ 25 °C m²/(V·s) @ 25 °C °C

Ge Si GaAs

0.39 0.14 0.85 —

0.19 0.05 0.05 —

70 to 100 150 to 200 150 to 200 150 to 200

Al-Si junction 0.3

Table 6 Semiconductor material characteristics

The junction forward voltage is the voltage applied to the emitter-base junction of a BJT in order to make the base conduct a specified current. The current increases exponentially as the junction forward voltage is increased. The values given in the table are typical for a current of 1 mA (the same values apply to semiconductor diodes). The lower the junction forward voltage the better,

as this means that less power is required to "drive" the transistor. The junction forward voltage for a given current decreases with increase in temperature. For a typical silicon junction the change is approximately −2.1 mV/°C.[14] The density of mobile carriers in the channel of a MOSFET is a function of the electric field forming the channel and of various other phenomena such as the impurity level in the channel. Some impurities, called dopants, are introduced deliberately in making a MOSFET, to control the MOSFET electrical behavior. The electron mobility and hole mobility columns show the average speed that electrons and holes diffuse through the semiconductor material with an electric field of 1 volt per meter applied across the material. In general, the higher the electron mobility the faster the transistor. The table indicates that Ge is a better material than Si in this respect. However, Ge has four major shortcomings compared to silicon and gallium arsenide: • • • • its maximum temperature is limited it has relatively high leakage current it cannot withstand high voltages it is less suitable for fabricating integrated circuits

Because the electron mobility is higher than the hole mobility for all semiconductor materials, a given bipolar NPN transistor tends to be faster than an equivalent PNP transistor type. GaAs has the highest electron mobility of the three semiconductors. It is for this reason that GaAs is used in high frequency applications. A relatively recent FET development, the high electron mobility transistor (HEMT), has a heterostructure (junction between different semiconductor materials) of aluminium gallium arsenide (AlGaAs)-gallium arsenide (GaAs) which has double the electron mobility of a GaAs-metal barrier junction. Because of their high speed and low noise, HEMTs are used in satellite receivers working at frequencies around 12 GHz. Max. junction temperature values represent a cross section taken from various manufacturers' data sheets. This temperature should not be exceeded or the transistor may be damaged. Al-Si junction refers to the high-speed (aluminum-silicon) semiconductor-metal barrier diode, commonly known as a Schottky diode. This is included in the table because some silicon power IGFETs have a parasitic reverse Schottky diode formed between the source and drain as part of the fabrication process. This diode can be a nuisance, but sometimes it is used in the circuit.

3.7.6 packaging

Fig 16 Through-hole transistors (tape measure marked in centimetres)

Transistors come in many different packages (chip carriers) (see images). The two main categories are through-hole (or leaded), and surface-mount, also known as surface mount device (SMD). The ball grid array (BGA) is the latest surface mount package (currently only for large transistor arrays). It has solder "balls" on the underside in place of leads. Because they are smaller and have shorter interconnections, SMDs have better high frequency characteristics but lower power rating. Transistor packages are made of glass, metal, ceramic or plastic. The package often dictates the power rating and frequency characteristics. Power transistors have large packages that can be clamped to heat sinks for enhanced cooling. Additionally, most power transistors have the collector or drain physically connected to the metal can/metal plate. At the other extreme, some surface-mount microwave transistors are as small as grains of sand. Often a given transistor type is available in different packages. Transistor packages are mainly standardized, but the assignment of a transistor's functions to the terminals is not: different transistor types can assign different functions to the package's terminals. Even for the same transistor type the terminal assignment can vary (normally indicated by a suffix letter to the part number- i.e. BC212L and BC212K).

CHAPTER 4 – VISUAL BASIC

Paradigm Developer Latest release Typing discipline Influenced by Influenced OS

Object-oriented and Event-driven Microsoft VB6/ 1998 Static, strong QuickBASIC Visual Basic .NET, Gambas Microsoft Windows, MS-DOS

Table 7 characteristics of visual basic

VISUAL BASIC is a high level programming language which was evolved from the earlier DOS version called BASIC. BASIC means Beginners' All-purpose Symbolic Instruction Code. It is a very easy programming language to learn. The codes look a lot like English Language. Different software companies produced different version of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC ,IBM BASICA and so on. However, it seems people only use Microsoft Visual Basic today, as it is a well developed programming language and supporting resources are available everywhere. Now, there are many versions of VB exist in the market, the most popular one and still widely used by many VB programmers is none other than Visual Basic 6. We also have VB.net, VB2005 and the latest VB2008, which is a fully object oriented programming (OOP) language. It is more powerful than VB6 but looks more complicated to master. VISUAL BASIC is a VISUAL and events driven Programming Language. These are the main divergence from the old BASIC. In BASIC, programming is done in a text-only environment and the program is executed sequentially. In VB, programming is done in a graphical environment. In the old BASIC, you have to write program codes for each graphical object you wish to display it on screen, including its position and its color. However, In VB , you just need to drag and drop

any graphical object anywhere on the form, and you can change its color any time using the properties windows. On the other hand, because users may click on a certain object randomly, so each object has to be programmed independently to be able to response to those actions (events). Therefore, a VB Program is made up of many subprograms, each has its own program codes, and each can be executed independently and at the same time each can be linked together in one way or another. it is the third-generation event-driven programming language and integrated development environment (IDE) from Microsoft for its COM programming model. VB is also considered a relatively easy to learn and use programming language, because of its graphical development features and BASIC heritage. Visual Basic was derived from BASIC and enables the rapid application development (RAD) of graphical user interface (GUI) applications, access to databases using Data Access Objects, Remote Data Objects, or ActiveX Data Objects, and creation of ActiveX controls and objects. Scripting languages such as VBA and VBScript are syntactically similar to Visual Basic, but perform differently. A programmer can put together an application using the components provided with Visual Basic itself. Programs written in Visual Basic can also use the Windows API, but doing so requires external function declarations. The final release was version 6 in 1998. Microsoft's extended support ended in March 2008 and the designated successor was Visual Basic .NET (now known simply as Visual Basic).

Figure 17 form of vb

4.1Language features
• • • • • • • • • • • Full set of objects - you 'draw' the application Lots of icons and pictures for your use Response to mouse and keyboard actions Clipboard and printer access Full array of mathematical, string handling, and graphics functions Can handle fixed and dynamic variable and control arrays Sequential and random access file support Useful debugger and error-handling facilities Powerful database access tools ActiveX support Package & Deployment Wizard makes distributing your applications simple

Like the BASIC programming language, Visual Basic was designed to be easy to learn and use. 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 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 key press 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 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 entry. 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 DLL's) and threading models.

4.2 Characteristics present in Visual Basic
Visual Basic has the following traits which differ from C-derived languages: • Multiple assignment available in C language is not possible. A = B = C does not imply that the values of A, B and C are equalled. The boolean result of "Is B = C?" is stored in A. The result stored in A could therefore be false(0) or true(-1) • Boolean constant True has numeric value −1.[3] This is because the Boolean data type is stored as a 16-bit signed integer. In this construct −1 evaluates to 16 binary 1s (the Boolean value True), and 0 as 16 0s (the Boolean value False). This is apparent when performing a Not operation on a 16 bit signed integer value 0 which will return the integer value −1, in other words True = Not False. This inherent functionality becomes especially useful when performing logical operations on the individual bits of an integer such as And, Or, Xor and Not.[4] This definition of True is also consistent with BASIC since the early 1970s Microsoft BASIC implementation and is also related to the characteristics of CPU instructions at the time.



Logical and bitwise operators are unified. This is unlike some C-derived languages (such as Perl), which have separate logical and bitwise operators. This again is a traditional feature of BASIC.



Variable array base. Arrays are declared by specifying the upper and lower bounds in a way similar to Pascal and Fortran. It is also possible to use the Option Base statement to set the default lower bound. Use of the Option Base statement can lead to confusion when reading Visual Basic code and is best avoided by always explicitly specifying the lower bound of the array. This lower bound is not limited to 0 or 1, because it can also be set by declaration. In this way, both the lower and upper bounds are programmable. In more subscript-limited languages, the lower bound of the array is not variable. This uncommon trait does exist in Visual Basic .NET but not in VBScript.
OPTION BASE

was introduced by ANSI, with the standard for ANSI Minimal BASIC in

the late 1970s. • • Relatively strong integration with the Windows operating system and the Component Object Model. Banker's rounding as the default behavior when converting real numbers to integers with the Round function. • Integers are automatically promoted to reals in expressions involving the normal division operator (/) so that division of an odd integer by an even integer produces the intuitively correct result. There is a specific integer divide operator (\) which does truncate. • By default, if a variable has not been declared or if no type declaration character is specified, the variable is of type Variant. However this can be changed with Deftype statements such as DefInt, DefBool, DefVar, DefObj, DefStr. There are 12 Deftype statements in total offered by Visual Basic 6.0. The default type may be overridden for a specific declaration by using a special suffix character on the variable name (# for Double, ! for Single, & for Long, % for Integer, $ for String, and @ for Currency) or using the key phrase As (type). VB can also be set in a mode that only explicitly declared variables can be used with the command Option Explicit.

4.3Toolbox Tools

Contols are the building blocks with which you assemble your Visual Basic 6.0 program. The Visual Basic 6.0 Toolbox is a palette of controls, and you build your user interface by selecting controls from the Visual Basic 6.0 Toolbox and placing them on your forms.

Figure18 tool box

4.4 Control Categories
There are three broad categories of controls in Visual Basic: • Intrinsic controls, such as the command button and frame controls. These controls are contained inside the Visual Basic .exe file. Intrinsic controls are always included in the toolbox, unlike ActiveX controls and insertable objects, which can be removed from or added to the toolbox. • ActiveX controls, which exist as separate files with a .ocx file name extension. These include controls that are available in all editions of Visual Basic (DataCombo, DataList controls, and so on) and those that are available only in the Professional and Enterprise editions (such as Listview, Toolbar, Animation, and Tabbed Dialog). Many third-party ActiveX controls are also available. Note Controls with the .vbx file name extension use older technology and are found in applications written in earlier versions of Visual Basic. When Visual Basic opens a

project containing a .vbx control, the default behavior is to replace the .vbx control with an .ocx control, but only if an .ocx version of the control is available. See "Updating Older Versions of Visual Basic Controls" later in this chapter for information on updating controls to the .ocx format. • Insertable Objects, such as a Microsoft Excel Worksheet object containing a list of all your company's employees, or a Microsoft Project Calendar object containing the scheduling information for a project. Since these can be added to the toolbox, they can be considered controls. Some of these objects also support Automation (formerly called OLE Automation), which allows you to program another application's objects from within a Visual Basic application. See "Programming with Objects," for more information on Automation.

4.5 Evolution of Visual Basic
VB 1.0 was introduced in 1991. The drag and drop design for creating the user interface is derived from a prototype form generator developed by Alan Cooper and his company called Tripod. Microsoft contracted with Cooper and his associates to develop Tripod into a programmable form system for Windows 3.0, under the code name Ruby (no relation to the Ruby programming language). Tripod did not include a programming language at all. Microsoft decided to combine Ruby with the Basic language to create Visual Basic. The Ruby interface generator provided the "visual" part of Visual Basic and this was combined with the "EB" Embedded BASIC engine designed for Microsoft's abandoned "Omega" database system. Ruby also provided the ability to load dynamic link libraries containing additional controls (then called "gizmos"), which later became the VBX interface[5].

4.6 Timeline of Visual Basic (VB1 to VB6)
• • Project 'Thunder' was initiated Visual Basic 1.0 (May 1991) was released for Windows at the Comdex/Windows World trade show in Atlanta, Georgia.

Fig19 Visual Basic for MS-DOS



Visual Basic 1.0 for DOS was released in September 1992. The language itself was not quite compatible with Visual Basic for Windows, as it was actually the next version of Microsoft's DOS-based BASIC compilers, QuickBASIC and BASIC Professional Development System. The interface used the "COW" (Character Oriented Windows) interface, using extended ASCII characters to simulate the appearance of a GUI.



Visual Basic 2.0 was released in November 1992. The programming environment was easier to use, and its speed was improved. Notably, forms became instantiable objects, thus laying the foundational concepts of class modules as were later offered in VB4.



Visual Basic 3.0 was released in the summer of 1993 and came in Standard and Professional versions. VB3 included version 1.1 of the Microsoft Jet Database Engine that could read and write Jet (or Access) 1.x databases.



Visual Basic 4.0 (August 1995) was the first version that could create 32-bit as well as 16-bit Windows programs. It also introduced the ability to write non-GUI classes in Visual Basic. Incompatibilities between different releases of VB4 caused installation and operation problems. While previous versions of Visual Basic had used VBX controls, Visual Basic now used OLE controls (with files names ending in .OCX) instead. These were later to be named ActiveX controls.



With version 5.0 (February 1997), Microsoft released Visual Basic exclusively for 32-bit versions of Windows. Programmers who preferred to write 16-bit programs were able to import programs written in Visual Basic 4.0 to Visual Basic 5.0, and Visual Basic 5.0 programs can easily be converted with Visual Basic 4.0. Visual Basic 5.0 also introduced the ability to create custom user controls, as well as the ability to compile to native Windows executable code, speeding up calculation-intensive code execution. A free, downloadable Control Creation Edition was also released for creation of ActiveX controls. It was also used as an introductory form of Visual Basic: a regular .exe project could be created and run in the IDE, but not compiled.



Visual Basic 6.0 (Mid 1998) improved in a number of areas

[6]

including the ability to

create web-based applications. VB6 has entered Microsoft's "non-supported phase" as of March 2008. Although the Visual Basic 6.0 development environment is no longer supported, the runtime is supported on Windows Vista, Windows Server 2008 and Windows 7. • Mainstream Support for Microsoft Visual Basic 6.0 ended on March 31, 2005. Extended support ended in March 2008.[8] In response, the Visual Basic user community expressed its grave concern and lobbied users to sign a petition to keep the product alive.[9] Microsoft has so far refused to change their position on the matter. (but see) Ironically, around this time (2005), it was exposed that Microsoft's new anti-spyware offering, Microsoft AntiSpyware (part of the GIANT Company Software purchase), was coded in Visual Basic 6.0.[11]Its replacement, Windows Defender, was rewritten as C++ code.

4.7 Derivative languages
Microsoft has developed derivatives of Visual Basic for use in scripting. Visual Basic itself is derived heavily from BASIC, and subsequently has been replaced with a .NET platform version. Some of the derived languages are: • Visual Basic for Applications (VBA) is included in many Microsoft applications (Microsoft Office), and also in many third-party products like SolidWorks, AutoCAD, WordPerfect Office 2002, ArcGIS and Sage Accpac ERP. There are small inconsistencies in the way VBA is implemented in different applications, but it is largely the same language as VB6 and uses the same runtime library.



VBScript is the default language for Active Server Pages. It can be used in Windows scripting and client-side web page scripting. Although it resembles VB in syntax, it is a separate language and it is executed by vbscript.dll as opposed to the VB runtime. ASP and VBScript should not be confused with ASP.NET which uses the .NET Framework for compiled web pages.



Visual Basic .NET is Microsoft's designated successor to Visual Basic 6.0, and is part of Microsoft's .NET platform. Visual Basic.Net compiles and runs using the .NET Framework. It is not backwards compatible with VB6. An automated conversion tool exists, but fully automated conversion for most projects is impossible.[13]

• •

Star Basic is a Visual Basic compatible interpreter included in StarOffice suite, developed by Sun Microsystems. Gambas is a Visual Basic inspired free software programming language for GNU/Linux. It is not a clone of Visual Basic, but it does have the ability to convert Visual Basic programs to Gambas.



KBasic is a Visual Basic inspired free software programming language for Linux, Mac and Windows. It is not a clone of Visual Basic, but it does have the ability to convert Visual Basic programs to KBasic.

4.8 Performance and other issues
Earlier counterparts of Visual Basic (prior to version 5) compiled the code to P-Code or Pseudo code only. Visual Basic 5 and 6 are able to compile the code to either native or P-Code as the programmer chooses. The P-Code is interpreted by the language runtime, also known as virtual machine, implemented for benefits such as portability and small code. However, it usually slows down the execution by adding an additional layer of interpretation of code by the runtime although small amounts of code and algorithms can be constructed to run faster than the compiled native code. Visual Basic applications require Microsoft Visual Basic runtime MSVBVMxx.DLL, where xx is the relevant version number, either 50 or 60. MSVBVM60.dll comes as standard with Windows in all editions after Windows 98 while MSVBVM50.dll comes with all editions after Windows 95. A Windows 95 machine would however require inclusion with the installer of whichever dll was needed by the program.

Other criticisms levelled at Visual Basic editions prior to VB.NET include: • • • • • • • Versioning problems associated with various runtime DLL's (see DLL hell) Poor support for object-oriented programming[15] Inability to create multi-threaded applications, without resorting to Windows API calls Lack of unicode support Inability to create Windows services Inability to create console applications Variant types have a greater performance and storage overhead than strongly typed programming languages

4.9 Legacy development and support
All versions of Visual Basic from 1.0 to 6.0 have been retired and are now unsupported by Microsoft. Visual Basic 6 programs can still run on Windows versions up to and including Vista, Windows Server 2008 and Windows 7, and the runtime is supported by Microsoft on these versions.[16]. Development and maintenance development for Visual Basic 6 is possible on Windows XP, Windows Vista and Windows 2003 using Visual Studio 6.0. Documentation for Visual Basic 6.0, its application programming interface and tools is best covered in the last MSDN release before Visual Studio.NET 2002. Later releases of MSDN focused on .NET development and had significant parts of the Visual Basic 6.0 programming documentation removed. Development for this type of legacy system can be done using a virtual machine with Windows 2003 or Windows XP, Visual Studio 6.0 and MSDN documentation. The Visual Basic IDE can be installed and used on Windows Vista, where it exhibits some minor incompatibilities which do not hinder normal software development and maintenance. As of August 2008, both Visual Studio 6.0 and the MSDN documentation mentioned above are available for download by MSDN subscribers.

4.10 Example code
Here is an example of the language: Code snippet that display a message box "Hello, World!" as the window Form loads:
Private Sub Form_Load() MsgBox "Hello, World!"

End Sub

CHAPTER 5 APPLICATION 5.)Applications
5.1) The motion detector is primirally desigend for secuirity system basially in night time 5.2) It would be easy to incorporate the camera into automatic doors. Doors are ideal to take a picture of people entering a building, as one always enters face-front. Normal doors can be used as well, provided you add a reed switch for the trigger signal. 5.3) Another interesting product could be an automated barrier capable to register number plate and driver of each car entering a parking lot. Or maybe you just like to have a look at what people is ringing your bell when you’re not at home.

5.4) Perhaps the most natural alternative use of the Witnesscam is as invehicle camera (this photo with the lorry was taken on a test drive). The trigger facility can start recording automatically as the engine ignites - or a tilt switch detects an excessive bump. The SD-card can collect precious evidence and survive an accident – something you may want to tell to your insurance in order to get a rebate. Young drivers may hate it, but an electronic eye can help making them drive more responsibly. 5.5) Managers must prevent fraudulent use of corporate cars, and need a means to verify that a vehicle – and consequently employees – was where they were intended to be. Delivery trucks, patrol squads, and even taxi can profitably adopt a cheap recording system.

5.6) Other times a vehicle or a machinery can cause injury or damage a property. It is the case of bulldozers, cranes, road rollers, mining and engineering vehicles, excavators… After an accident, Witnesscam evidence helps discovering how and why an accident occurred, pinpointing responsibilities, and making clear how to prevent it from happening again.

CHAPTER 6 COST EVALUATION

S.NO
1. 2. 3. 4.

COMPONENTS
ULN 2003 STEPPER MOTOR WEBCAM D TYPE 25 PIN PARALLEL PORT

NO OF COMPONENTS
1 1 1 1

RATE
50 250 800 25

TOTAL
50 250 800 25

5. 6. 7.

REGULATOR IC TRANSISTOR D TYPE 25 PIN MALE TO MALE CABLE

1 4 1

10 10 80

10 40 80

8. 9. 10. 11. 12. 13.

TRANSFORMER DIODES ZENER DIODES RESISTANCES CAPACITOR LED

1 AS REOUIRED AS REOUIRED AS REOUIRED AS REOUIRED AS REOUIRED

50 -

50 -

Table 8 cost evaluation

The cost of individual component is shown above in table. This cost is estimation of the electronic circuitry. There are some additional material used in this project these increase the cost of project. It also include the labour . So the total cost of project approximates 2000 Rs only

CHAPTER 7 COADING
7.1) SEREVR
Private Sub cmdsend_Click() Winsock1.SendData "server:" & txtmsg.Text txtchat.Text = txtchat.Text & "server:" & txtmsg.Text & vbNewLine txtmsg.Text = "" End Sub Private Sub Form_Load() Winsock1.Listen End Sub Private Sub txtmsg_Change() 'If txtmsg.Text = "on" Then 'MsgBox " good" 'Shape1.BackColor = &HFF00& 'End If End Sub Private Sub Winsock1_ConnectionRequest(ByVal requestID As Long) Winsock1.Close Winsock1.Accept requestID End Sub Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long) Winsock1.GetData dataarrived, vbString txtchat.Text = txtchat.Text & dataarrived & vbNewLine If dataarrived = "client:" Then 'MsgBox " good" Shape1.BackColor = &HFF00& Form2.Show Form1.Show End If

If dataarrived = "client:off" Then 'MsgBox " good" Shape1.BackColor = &HFF End If End Sub

Dim x As Boolean Dim n As Variant Dim i As Integer, Y As Integer, l As Integer, r As Boolean, ls As Boolean Dim value As Integer Dim ll As String

Private Sub Command1_Click() Dim i As Integer i = Val(Text1.Text) If i = 0 Then End If If i = 1 Then End If If i = 2 Then Call anticlkwise End If If i = 3 Then Call clkwise End If End Sub Private Sub Form_Load() Dim k As Integer Dim m As Integer 'Timer1.Enabled = True Timer2.Enabled = True 'wmp1.URL = VB.App.Path & "\u.wav" 'wmp1.Controls.play 'i = 3 'frmMain.Show 'Me.Hide End Sub 'Private Sub clkwise()

'Call PortOut(&H378, 2) ' ' 'End Sub 'Private Sub anticlkwise() ' 'Call PortOut(&H378, 2) ' 'End Sub Private Sub Text1_Change() If Text1.Text = "END" Then End End If End Sub 'Private Sub Timer1_Timer() ' ' Call clkwise 'Sleep (1000) 'Call PortOut(&H378, 0) ''Sleep (1000) ' Timer1.Enabled = False ' 'End Sub Private Sub Timer2_Timer() wmp1.URL = VB.App.Path & "\u.wav" wmp1.Controls.play End Sub

Private Sub Form_Load() Timer1.Enabled = True Me.Hide End Sub Private Sub Timer1_Timer() With Printer Printer.Print "alert!!!!!!!!!!!!!!! " '.FontBold = True Printer.Print "thief detected in area - poornima college of engineering,2nd floor, sitapura ,jaipur,rajasthan " '.FontItalic = True

Printer.Print "help!!!!!!!!!!! " '.FontBold = False '.FontItalic = False Printer.Print "help" Printer.Print "time -" & Time & " .EndDoc End With Timer1.Enabled = False End Sub

date - " & Date

7.2) CLIENT
Private Sub cmdconnect_Click() 'Winsock1.Connect txtip.Text, txtport.Text End Sub Private Sub cmdsend_Click() 'Winsock1.SendData "client:" & txtmsg.Text 'txtchat.Text = txtchat.Text & "client:" & txtmsg.Text & vbNewLine 'txtmsg.Text = "" 'txtmsg.Text = "" End Sub Private Sub Form_Load() 'txtip.Text = Winsock1.LocalIP this is written when lan is absent otherwise make this line as comment n type in textip the address of server txtip.Text = Winsock1.LocalIP Winsock1.Connect txtip.Text, txtport.Text End Sub Private Sub Timer1_Timer() Winsock1.SendData "client:" & txtmsg.Text txtchat.Text = txtchat.Text & "client:" & txtmsg.Text & vbNewLine txtmsg.Text = "" End Sub Private Sub txtchat_Change() If dataarrived = "client:" Then Form2.Show End If

End Sub Private Sub txtmsg_Change() 'If txtmsg.Text = "on" Then 'MsgBox " good" 'Shape1.BackColor = &HFF00& 'End If End Sub Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long) Winsock1.GetData dataarrived, vbString txtchat.Text = txtchat.Text & dataarrived & vbNewLine 'If dataarrived = "server: on" Then 'MsgBox " good" 'Shape1.BackColor = &HFF00& 'End If 'If dataarrived = "server: off" Then 'MsgBox " good" 'Shape1.BackColor = &HFF 'End If End Sub Dim x As Boolean Dim n As Variant Dim i As Integer, y As Integer, l As Integer, r As Boolean, ls As Boolean Dim value As Integer Dim ll As String

Private Sub Command1_Click() Dim i As Integer i = Val(Text1.Text) If i = 0 Then End If If i = 1 Then End If If i = 2 Then Call anticlkwise End If If i = 3 Then Call clkwise End If

End Sub Private Sub Form_Load() Call PortOut(&H378, 0) Dim k As Integer Dim m As Integer Timer1.Enabled = True Timer2.Enabled = True 'wmp1.URL = VB.App.Path & "\u.wav" 'wmp1.Controls.play i=3 frmMain.Show Me.Hide End Sub 'Private Sub clkwise() ''Call PortOut(&H378, 2) 'For i = 1 To 26 'Call PortOut(&H378, 1) 'Sleep (59) 'Call PortOut(&H378, 2) 'Sleep (59) 'Call PortOut(&H378, 4) 'Sleep (59) 'Call PortOut(&H378, 8) 'Sleep (59) ' 'Next i ' 'End Sub 'Private Sub anticlkwise() 'For i = 1 To 26 'Call PortOut(&H378, 8) 'Sleep (59) 'Call PortOut(&H378, 4) 'Sleep (59) 'Call PortOut(&H378, 2) 'Sleep (59) 'Call PortOut(&H378, 1) 'Sleep (59) ' 'Next i ''Call PortOut(&H378, 2) ' 'End Sub Private Sub Timer1_Timer()

For i = 1 To 13 Call PortOut(&H378, 1) Sleep (59) Call PortOut(&H378, 2) Sleep (59) Call PortOut(&H378, 4) Sleep (59) Call PortOut(&H378, 8) Sleep (59) Next i ' Call clkwise 'Sleep (1000) 'Call PortOut(&H378, 0) 'Sleep (1000) Timer1.Enabled = False End Sub Private Sub Timer2_Timer() wmp1.URL = VB.App.Path & "\ub.wav" wmp1.Controls.play End Sub 'Option Explicit '---------------------------Dim StdVar As Double Dim Promedio As Double Dim Suma As Double Dim CuentaIMG As Integer Dim CuentaCiclo(10) As Integer Dim SumaCuadr As Double Dim Matriz_Prom(10, 10) As Double Dim Matriz_Desvest(10, 10) As Double Dim Prom_Cadena(10) As Double Dim Prom_Cadena_Anterior(10) As Double Dim Desvest_Cadena(10) As Double Dim Umbral_Prom As Double Dim Umbral_Desvest As Double Dim SeHallenadoCadena(10) As Boolean Dim SeIncorporaNuePixel(10) As Boolean '---------------------------'---------------------------Dim lPicLeft As Single 'Long Dim lPicTop As Single 'Long

Dim lMoveX As Long Dim lMoveY As Long Dim bForwardMove As Boolean Dim bDownMove As Boolean Dim bMoving As Boolean Dim lTransColor As Long '---------------------------Const Ancho = 164 Const Alto = 124 Const Delta = 1000000 Dim Sheet1 As Object Dim ColorPunto As Long Dim MatrizPunto(1000) As Long Dim SumaPunto(10000) As Long Dim Locked As Boolean Dim i As Integer Dim j As Integer Dim UmbralTrFalse As Double Private c As ColorComponent Private Sub Command1_Click() Call PortOut(&H378, 3) Sleep (1000) Call PortOut(&H378, 0) Unload Form2 End Sub Private Sub Form_Load() Locked = False Picture1.AutoSize = True Dim lpszName As String * 100 Dim lpszVer As String * 100 Dim Caps As CAPDRIVERCAPS '----------------------------Timer1.Interval = BuscaValor(3) 'In the file "InfoPlanilla.txt" 'change the third value to 'increase or decrease surveillance ' cycles in frequency. '----------------------------Umbral_Prom = BuscaValor(1)

Umbral_Desvest = BuscaValor(2) UmbralTrFalse = BuscaValor(4) 'In the file "InfoPlanilla.txt" 'change the fourth value to 'increase or decrease sensibility to ' motion elements. '----------------------------'----------------------------'//Create Capture Window capGetDriverDescriptionA 0, lpszName, 100, lpszVer, 100 '// Retrieves driver info lwndC = capCreateCaptureWindowA(lpszName, WS_CAPTION Or WS_THICKFRAME Or WS_VISIBLE Or WS_CHILD, 0, 0, 160, 120, Me.hwnd, 0) '// Set title of window to name of driver SetWindowText lwndC, lpszName '// Set the video stream callback function capSetCallbackOnStatus lwndC, AddressOf MyStatusCallback capSetCallbackOnError lwndC, AddressOf MyErrorCallback '// Connect the capture window to the driver If capDriverConnect(lwndC, 0) Then capDriverGetCaps lwndC, VarPtr(Caps), Len(Caps) If Caps.fHasDlgVideoSource = 0 Then mnuSource.Enabled = False If Caps.fHasDlgVideoFormat = 0 Then mnuFormat.Enabled = False If Caps.fHasDlgVideoDisplay = 0 Then mnuDisplay.Enabled = False capPreviewScale lwndC, True '// preview rate in ms capPreviewRate lwndC, 66 '// previewing image from Webcam capPreview lwndC, True ResizeCaptureWindow lwndC End If Picture1.ScaleMode = vbPixels Picture1.AutoRedraw = True lPicLeft = 1 lPicTop = 1 MakeTopMost (hwnd)

End Sub Private Sub Form_Unload(Cancel As Integer) Form2.wmp1.Controls.stop Unload Form2 '// Disable all callbacks capSetCallbackOnVideoStream lwndC, vbNull capSetCallbackOnWaveStream lwndC, vbNull capSetCallbackOnCapControl lwndC, vbNull capSetCallbackOnError lwndC, vbNull capSetCallbackOnStatus lwndC, vbNull capSetCallbackOnYield lwndC, vbNull capSetCallbackOnFrame lwndC, vbNull End Sub Private Sub mnuAllocate_Click() Dim sFile As String * 250 Dim lSize As Long '// Setup swap file for capture lSize = 1000000 sFile = "C:\TEMP.AVI" capFileSetCaptureFile lwndC, sFile capFileAlloc lwndC, lSize End Sub Private Sub mnuAlwaysVisible_Click() mnuAlwaysVisible.Checked = Not (mnuAlwaysVisible.Checked) If mnuAlwaysVisible.Checked Then SetWindowPos Me.hwnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE Or SWP_NOMOVE Else SetWindowPos Me.hwnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE Or SWP_NOMOVE End If End Sub Private Sub mnuCompression_Click()

capDlgVideoCompression lwndC End Sub Private Sub mnuCopy_Click() capEditCopy lwndC End Sub Private Sub mnuDisplay_Click() capDlgVideoDisplay lwndC End Sub Private Sub mnuExit_Click() Unload Me End Sub Private Sub mnuFormat_Click() capDlgVideoFormat lwndC ResizeCaptureWindow lwndC End Sub Private Sub mnuPreview_Click() frmMain.StatusBar.SimpleText = vbNullString mnuPreview.Checked = Not (mnuPreview.Checked) capPreview lwndC, mnuPreview.Checked End Sub Private Sub mnuScale_Click() mnuScale.Checked = Not (mnuScale.Checked) capPreviewScale lwndC, mnuScale.Checked If mnuScale.Checked Then SetWindowLong lwndC, GWL_STYLE, WS_THICKFRAME Or WS_CAPTION Or WS_VISIBLE Or WS_CHILD Else SetWindowLong lwndC, GWL_STYLE, WS_BORDER Or WS_CAPTION Or WS_VISIBLE Or WS_CHILD

End If ResizeCaptureWindow lwndC End Sub Private Sub mnuSelect_Click() frmSelect.Show vbModal, Me End Sub Private Sub mnuSource_Click() capDlgVideoSource lwndC End Sub Private Sub mnuStart_Click() Dim sFileName As String Dim CAP_PARAMS As CAPTUREPARMS capCaptureGetSetup lwndC, VarPtr(CAP_PARAMS), Len(CAP_PARAMS) CAP_PARAMS.dwRequestMicroSecPerFrame = (1 * (10 ^ 6)) / 30 ' 30 Frames per second CAP_PARAMS.fMakeUserHitOKToCapture = True CAP_PARAMS.fCaptureAudio = False capCaptureSetSetup lwndC, VarPtr(CAP_PARAMS), Len(CAP_PARAMS) sFileName = "C:\myvideo.avi" capCaptureSequence lwndC capFileSaveAs lwndC, sFileName End Sub Private Sub StatusBar1_PanelClick(ByVal Panel As ComctlLib.Panel) End Sub Private Sub CargadePantalla() Picture1.Picture = Clipboard.GetData(vbCFDIB) End Sub Private Function ValoresLinea(Xa As Integer, Ya As Integer, Xb As Integer, Yb As Integer) As ParPromDest 'Yields Avg and StdVar for the specified line Dim i As Single, j As Single, ve As Double, Suma As Double, SumaCuadr As Double IniPunto = 1

If Yb - Ya > Xb - Xa Then 'Analysis through Y axis ve = (Xb - Xa) / (Yb - Ya) For j = Ya To Yb i = Int((j - Ya) * ve) + Xa GetColores Picture1, i, j, c Suma = Suma + c.SumaColInt SumaCuadr = SumaCuadr + (c.SumaColInt ^ 2) Next j ValoresLinea.Promedio = Int(Suma / (Yb - Ya + 1)) ValoresLinea.StdVar = Int(Sqr(((Yb - Ya + 1) * SumaCuadr - (Suma ^ 2)) / (Yb - Ya + 1) / (Yb - Ya))) Else 'Analysis through X axis ve = (Yb - Ya) / (Xb - Xa) For i = Xa To Xb j = Int((i - Xa) * ve) + Ya GetColores Picture1, i, j, c Suma = Suma + c.SumaColInt SumaCuadr = SumaCuadr + (c.SumaColInt ^ 2) Next i ValoresLinea.Promedio = Int(Suma / (Xb - Xa + 1)) ValoresLinea.StdVar = Int(Sqr(((Xb - Xa + 1) * SumaCuadr - (Suma ^ 2)) / (Xb - Xa + 1) / (Xb - Xa))) End If End Function Private Sub Picture1_Click() End Sub Private Sub Timer1_Timer() Dim DiagoPrinc As ParPromDest Dim Signal1 As Boolean '-----*-*-*-*-*-*-*-*-* Static DiagoPromAnte As Double Static Diferencia As Double Static DiferenciaAnte As Double Static SegDerivada As Double Static Contador As Integer '-----*-*-*-*-*-*-*-*-*

If Locked = False Then Pausa (10) Locked = True End If Signal1 = False capEditCopy lwndC: CargadePantalla '---*-*-*-*-*-*'Routine that counts each "Chain" Cycle DiagoPrinc = CicleaLinea(1, 58, 159, 60, 1) '---*-*-*-*-*-* If DiagoPromAnte <> 0 Then Diferencia = Abs(DiagoPromAnte - DiagoPrinc.Promedio) If Diferencia > UmbralTrFalse Then DiagoPromAnte = DiagoPrinc.Promedio Signal1 = True Else DiagoPromAnte = DiagoPrinc.Promedio End If Else DiagoPromAnte = DiagoPrinc.Promedio End If ' the second derivative allows to make the difference ' between an out-of Avg. image and the normal lightning persitence ' the Avg. value has to overcome when restoring to usual image ' conditions SegDerivada = Diferencia - DiferenciaAnte If SegDerivada > 0 Then DiferenciaAnte = Diferencia If Signal1 = True Then Contador = Contador + 1 Debug.Print "Saving", Contador SavePicture Picture1.Image, App.Path & "\image\ImageNo." & Contador & ".jpg" If Contador = 1 Then Form1.Hide Form2.Show End If End If Else DiferenciaAnte = Diferencia End If End Sub Private Function CicleaLinea(Xa As Integer, Ya As Integer, Xb As Integer, Yb As Integer, NL As Integer) As ParPromDest

Dim Resultado As ParPromDest Resultado = ValoresLinea(Xa, Ya, Xb, Yb) If CuentaCiclo(NL) = 9 Then ' Cycle n°9 already executed ' CuentaCiclo(NL) = 0 SeHallenadoCadena(NL) = True End If CuentaCiclo(NL) = CuentaCiclo(NL) + 1 '---*-*-*-*-*-* '---*-*-*-*-*-* '---*-*-*-*-*-* If CuentaCiclo(NL) = 1 Then 'First Value added to "Chain" If SeHallenadoCadena(NL) = False Then Matriz_Desvest(1, NL) = Resultado.StdVar Matriz_Prom(1, NL) = Resultado.Promedio SeIncorporaNuePixel(NL) = True Else SeIncorporaNuePixel(NL) = False '---*-*-*-*-*-* ' Condition for adding latest Value to "Chain" If Abs(Matriz_Desvest(9, NL) - Resultado.StdVar) < Umbral_Desvest And Abs(Matriz_Prom(9, NL) - Resultado.Promedio) < Umbral_Prom Then Matriz_Desvest(CuentaCiclo(NL), NL) = Resultado.StdVar Matriz_Prom(CuentaCiclo(NL), NL) = Resultado.Promedio SeIncorporaNuePixel(NL) = True End If '---*-*-*-*-*-*-*-*-*-*-*-* PROMEDIAR_CADENA (NL) '---*-*-*-*-*-*-* ' Condition for handling Image saving If Abs(Desvest_Cadena(NL) - Resultado.StdVar) > Umbral_Desvest And Abs(Prom_Cadena(NL) - Resultado.Promedio) > Umbral_Prom Then CuentaIMG = CuentaIMG + 1 End If End If Else ' CuentaCiclo(NL) >= 2 Then '---*-*-*-*-*-* SeIncorporaNuePixel(NL) = False If Abs(Matriz_Desvest(CuentaCiclo(NL) - 1, NL) - Resultado.StdVar) < Umbral_Desvest And Abs(Matriz_Prom(CuentaCiclo(NL) - 1, NL) - Resultado.Promedio) < Umbral_Prom Then Matriz_Desvest(CuentaCiclo(NL), NL) = Resultado.StdVar Matriz_Prom(CuentaCiclo(NL), NL) = Resultado.Promedio SeIncorporaNuePixel(NL) = True End If

PROMEDIAR_CADENA (NL) If Abs(Desvest_Cadena(NL) - Resultado.StdVar) > Umbral_Desvest And Abs(Prom_Cadena(NL) - Resultado.Promedio) > Umbral_Prom Then CuentaIMG = CuentaIMG + 1 End If End If If SeIncorporaNuePixel(NL) = False Then CuentaCiclo(NL) = CuentaCiclo(NL) - 1 End If CicleaLinea.Promedio = Prom_Cadena(NL) CicleaLinea.StdVar = Desvest_Cadena(NL) End Function Private Sub PROMEDIAR_CADENA(NL As Integer) Dim j As Integer If SeIncorporaNuePixel(NL) = True Then If SeHallenadoCadena(NL) = True Then Prom_Cadena(NL) = (Prom_Cadena(NL) * 8 + Matriz_Prom(CuentaCiclo(NL), NL)) / 9 Desvest_Cadena(NL) = (Desvest_Cadena(NL) * 8 + Matriz_Desvest(CuentaCiclo(NL), NL)) / 9 Else Prom_Cadena(NL) = 0: Desvest_Cadena(NL) = 0 For j = 1 To 9 If Matriz_Prom(j, NL) = 0 And Matriz_Desvest(j, NL) = 0 Then Exit For Prom_Cadena(NL) = Prom_Cadena(NL) + Matriz_Prom(j, NL) Desvest_Cadena(NL) = Desvest_Cadena(NL) + Matriz_Desvest(j, NL) Next j If j <> 1 Then Prom_Cadena(NL) = Prom_Cadena(NL) / (j - 1) Desvest_Cadena(NL) = Desvest_Cadena(NL) / (j - 1) End If End If End If ' No new pixel added so there is ' No need for calculating new avg. End Sub Private Sub Pausa(TimePause As Variant)

Dim Inicio ''---------------------------------------------Inicio = Timer ' Sets starting time for pause (in sec.) Do While Timer < Inicio + TimePause DoEvents 'Shifts to other process Loop End Sub Private Function BuscaValor(i As Integer) As String Dim LeeString, cuenta Open App.Path & "\InfoPlanilla.txt" For Input As #1 For cuenta = 1 To i Input #1, LeeString Next cuenta Close #1 BuscaValor = LeeString End Function

Option Explicit Private Sub cmdCancel_Click() Unload Me End Sub Private Sub cmdSelect_Click() Dim sTitle As String Dim Caps As CAPDRIVERCAPS If cmboSource.ListIndex <> -1 Then '// Connect the capture window to the driver If capDriverConnect(lwndC, cmboSource.ListIndex) Then '// Get the capabilities of the capture driver capDriverGetCaps lwndC, VarPtr(Caps), Len(Caps) '// If the capture driver does not support a dialog, grey it out '// in the menu bar. frmMain.mnuSource.Enabled = Caps.fHasDlgVideoSource frmMain.mnuFormat.Enabled = Caps.fHasDlgVideoFormat frmMain.mnuDisplay.Enabled = Caps.fHasDlgVideoDisplay sTitle = cmboSource.Text SetWindowText lwndC, sTitle

ResizeCaptureWindow lwndC End If End If Unload Me End Sub Private Sub Form_Load() Dim lpszName As String * 100 Dim lpszVer As String * 100 Dim x As Integer Dim lResult As Long Dim Caps As CAPDRIVERCAPS '// Get a list of all the installed drivers x=0 Do lResult = capGetDriverDescriptionA(x, lpszName, 100, lpszVer, 100) '// Retrieves driver info If lResult Then cmboSource.AddItem lpszName x=x+1 End If Loop Until lResult = False '// Get the capabilities of the current capture driver lResult = capDriverGetCaps(lwndC, VarPtr(Caps), Len(Caps)) '// Select the driver that is currently being used If lResult Then cmboSource.ListIndex = Caps.wDeviceIndex End Sub

CHAPTER 8 CONCLUSION
Security systems in present world had turned out to be a mandatory system for every organization. Industries, workshops, factories, banks, offices, shops (especially -Jewellery shops) and even at home these days we find various kind of security systems based on different technologies. In other words Security Systems is 'The need of Hour '. Keeping in mind every ones need we Final year students of Poornima college of engineering, Electronics and Communication Branch planned to develop such a system which is capable to meet requirements of every organization from small residential areas to largely scaled Hytech Bank. In this security system we employed Visual Basic Language .Specifically in this we focused towards the 'IMAGE PROCESSING' modules of Visual Basic Programming. Now as we started developing the code we found the need of Interfacing Computer System with Hardware. For that we also learned Parallel Port Programming of Visual Basic. This gave us an idea to correlate our developed code of Visual Basic with Embedded System Technology. Our developed system is a MULTI COMPUTER BASED SYSTEM which uses at least two computers connected via LAN/WAN/MAN. The whole system consists of only one system

named as SERVER while other Multiple Computers are named as CLIENTS. The server system is always kept in ON condition. It is equipped with a Speaker and a Printer. Server is generally kept at HOME (manager or owner of the shop)/CONTROL ROOM (Police Station).Now the Client System is kept in area where security is to be provided. The Client System is equipped with a Webcam and a Speaker. Both of these systems are connected to each other Via LAN/WAN/MAN. The utility of this system lies generally during Night hours or holidays when there is absence of the staff members. To understand how this System works let us take an example of a jewellery shop. The Client Systems are kept at different places of the shop where the security is to be provided. And the Server System is kept at the home of the owner of the shop. Say at 3 a.m (midnight hours) a thief enters the shop. Now here this Security System comes into action. The Client System Detects change in Motion and starts capturing the Images of the thief at every interval of 2 seconds. It switches On the Alarm of the shop so as to make the Gatekeeper of the shop alert and simultaneously sends ALERT signals to the remote computer i.e. SERVER. Now the Server System which is kept at home of Owner of the shop receives the alert signals from the Client .Server switches on the audio file as Alarm by making the owner of the shop aware of some mishap going on at his Shop. The Client System in the form of alert signal sends the exact Date, Time and the exact location of Area of Theft in the shop(say floor no., room no. etc).After receiving this information the Server System which is also equipped with a Printer takes out the print out of all these valuable information. Now with the help of this Security System we can get a series of Images of thief which are stored in Client Computer System. We also get the exact information of the date, time and area at the time of theft itself. We have designed this system with a notion in mind to reduce the crime rate (Theft cases) in our city. Hope this System successfully meets every organization’s requirements.

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close