A PROJECT REPORTONAUTOMATIC FIRE CONTROL SYSTEM IN RAILWAYSSubmitted in partial fulfillment of the requirements for the award of the degree of

Bachelor of TechnologyinELECTRONICS AND COMMUNICATION ENGINEERING

UNDER THE GUIDANCE OF

Giving Wings to ThoughtsDEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERINGST. PETERS ENGINEERING COLLEGE(Approved by AICTE & Affiliated to Jawaharlal Nehru Technological University-Hyderabad)Opp. A.P. Forest Academy, Dhoolapally (V), Medchal (M), R.R. District, Hyderabad2012-2016

CERTIFICATETin partial fulfillment of the requirements for the award of the degree of Bachelor of Technology in Electronics and Communication Engineering from Jawaharlal Nehru Technological University- Hyderabad during the academic year 2012-2016.

INTERNAL GUIDEProf .S.ISWARIYAM. E,ECE DepartmentHEAD OF THE DEPARTMENTProf. R. PRAKASH RAOM. Tech, (Ph.D.)ECE Department

PRINCIPALDr. E. L. NAGESHB.Tech, M.Tech, Ph.D, MISTE, FIEEXTERNAL EXAMINER

ACKNOWLEDGEMENTIt gives us immense pleasure to express our deepest sense of gratitude and sincere thanks to our highly respected and esteemed principal DR.E.L.NAGESH, for providing the necessary facilities to complete the project successfully.We deeply express our sincere thanks to our Head of the Department Prof.R.PRAKASH RAO Department of Electronics and Communication Engineering for encouraging and allowing us to present the project.We also take the opportunity to express our profound gratitude and deep regards to our guide S.ISWARIYA Assistant professor, for his exemplary guidance, monitoring and constant encouragement throughout the course of this thesis. The blessings, help and guidance given by him time to time shall carry us a long way in the journey of life on which we are about to embark.It is our privilege to express our sincerest regards to our project coordinator K.B.MADHAVI Assistant professor, for his valuable inputs, able guidance, encouragement, whole-hearted cooperation and construction criticism throughout the duration of our project.We take this opportunity to thank all our lecturers of our department for their support and encouragement towards our project.

N.VENKATA KRISHNA 12BK1A04B3V.BABU NAIK 13BK5A0423V.KURUMAIAH 13BK5A0424

INDEX Page nos1.INTRODUCTION: 1.1 Block diagram9 1.2 Fire detection and control 10 1.3 Circuit diagram and description111.4Pin diagram of 4049 and 4050132.POWER SUPPLY: 2.1 Over view14 2.2 AC waveforms 15 2.3 Rectification unfiltered power supplies 16 2.4 Rectification filtered power supplies 19 2.5 Average DC value21 2.6 Diode conduction and peak diode current223.LM35 HEAT SENSOR: 3.1 LM35 Description 24 3.2 Working of an LM35 25 3.3 Using of an LM35 25 3.4 Advantages of LM35 274. SEQUENTIAL SWITCHING ICLM39144.1 IC LM3914 description 28 4.2 LM3914 features 29 4.3 LM35 and LM3914 interfacing circuit diagram29 Page nos5.RELAY WITH RELAY DRIVER:5.1 Description of relay 315.2 DC relay driver circuit 315.3 AC relay driver circuit 335.4Generic Relay driver circuit 34

6. UM3561 SIREN GENERATOR: 6.1 UM3561 description 36 6.2 Pin diagram of UM3561 37 6.3 Tone selection37

WORKING AND ADVANTAGES

OUTPUT 40-42

FUTURE SCOPE AND CONCLUSION 42

REFERENCES 43

List of figures:Fig no.Figure name Page no.Fig 1.1 Block diagram9Fig 1.2 Process of control10Fig 1.3Circuit diagram of fire control system11Fig 1.4 Pin diagram of 4049 and 4050 13Fig 2.1Two cycles of sinusoidal waveforms15Fig 2.2Half wave rectifier circuit17 Fig 2.3Full wave rectifier with center tapped transform17Fig 2.4Full wave or bridge rectifier18Fig 2.5Filtered power supply circuit diagram19Fig 2.6Filtered waveforms20Fig 2.7Average dc waveforms 21Fig 2.8Diodes D1 & D2 waveforms 22Fig 3.1 Pictorial representation of LM35 24Fig 3.2LM35 on circuit board26Fig 3.3LM35 pin diagram 26Fig 4.1 pictorial representation of LM3914 28Fig 4.2LM3914 pin description 28Fig 4.3 LM35 and LM3914 interfacing circuit diagram 30Fig 5.1 Pictorial representation of reley driver 31Fig 5.2 DC relay driver circuit diagram33Fig 5.3 AC relay driver circuit diagram 34

Fig 5.4 Relay driver circuits 35Fig 6.1 Internal block diagram of UM3561 36Fig 6.2 Pin diagram of UM3561 37Fig 6.3 Circuit diagram for tone selection 37

Abstract

Fire alarm system plays an important role in maintaining and monitoring the safe of all kind environments and situations. The main objective of this project is to make a fire control system with low costThe Present project will help the railways to safe guard from the Fire Accidents automatically in Sequential manner. A remedy to reduce the death loss occurring due to fire accidents in trains is presented. Fire on a running train is more catastrophic then on a stationary one, since fanning by winds helps spread the fire to other coaches. When these accidents are occurring in remote areas or during night times the loss or damage being caused is at higher rates, the damage is heavier due to improper reach of service at right time due to improper communication. This time delay is causing heavier damage, thus eliminating the time between when an accident occurs and when first responders are dispatched to the scene decreases the damage, this project help in notifying the passengers and emergency services. It consists of sensors. Once the sensors attached in the compartments of train sense the smoke detection, it assumes a fire accident. The controller assumes it has an emergency and starts the buzzer Whenever fire occurs the sensor will detects and starts alerting the security people for further controlling.It has three main systems, 1) the detection system, 2) the monitoring system, 3) the appliance system. The detection system operates as the fire detector. The appliance system has components like buzzer for alarming and motor pump to stop the fire. The system detects the smoke, heat sensed by the detector. Finally when the sensors from each level triggered individually, the water flushes to the affected zone to stop the fire.

1.INTRODUCTION

1.1 BLOCK DIAGRAM

Sequential Switching Using LM3914LM35 Heat SensorRegulated Power Supply (5V)

Siren Using UM3561Relay Drivers with relaysLED Indication

Flasher and water pump.

Fig 1.1 Block diagram of automatic fire control system in railways

1.2 FIRE DETECTION AND CONTROLBLOCK DIAGRAM:

FIRE SENSOR

IC SECTION

INDICATORRELAY DRIVERS

Fig 1.2 Process of fire controlFire is the most hazardous natural forces. Sensing fire and fighting it in the early stages can prevent losses to a great extent. Sensing fire electronically has become one of the most reliable fire-fighting techniques today. Sensing fire needs reliable smoke/fire sensors. Thermisters can sense fire depending on temperature increase principle. We can also use opto devices to sense smoke. Some sensors like figaro TGS gas sensors are used for fire sensing which is expensive and are not easily available. The system pretends here uses the most common yet very reliable bimetallic strip of a tube light starter as a heat sensor. The system, besides giving an alarm, also visually indicates the exact position where the fire has taken place. This system becomes very necessary in large multinational companies, hotels etc. It is very flexible and can take inputs from any number ofsensors. It is very simple to construct and is quite economical too.

1.3 CIRCUIT DIAGRAM:

Fig 1.3 Circuit diagram of fire control system

CIRCUIT DISCRIPTION:

The entire system works on a very simple principle. The bimetallic strip acts as a switch on the corresponding latch circuit. Here latching property is needed so that once the fire is sensed the alarm remains on until adequate precautions are taken. When the bimetallic strip gets heated due to the fire flame, it connects the positive supply line to the input of digital latch circuit, thus latching the latch. The digital latch circuit is built around easily available CMOS inverter CD4049 ICs.When sensor A is operated, the input of gate N2 (pin5) is at logic 1 through the 680-ohm limiting resistor. After two inversions, output of N1 (pin2) is at logic 1 which fed back through switching diode IN4148 to the input of N2, thus latching the circuit. LED2 connected across the output of N1 and ground indicates the particular position where sensor A is installed, indirectly indicating the phase where the fire has occurred. At this same time, diode D8 conducts and provides base bias to transistors T1 and the relay operates the hooter or an electric bell. The 0.01mF capacitor at input of latch circuit filters the noise pick-up by long wires leading to sensors, thus preventing any false triggering of the alarm. Switch S1 acts as master reset switch. OR logic is implemented at the base of transistor T1 to sense signal from each sensor. In this circuit only six sensors are shown but they can be increased without changing the main circuit.

1.4 PIN DIAGRAM:

Fig 1.4 Pin diagram of 4049 and 4050

2.POWER SUPPLY

2.1 Overview RequirementsBefore designing any power supply the load requirements must be known. It is always a good idea to take the worst case scenario when making this decision. For example if the circuit is designed to draw 1 amp at 12 volts, assume that component tolerances are 20% and design to meet these requirements with at least 20-50% reserve current, in this example we design a power supply which could safely deliver 12 volts at 1.5 amps without overheating.

Transformer Regulation and EfficiencyA transformer is very efficient at converting AC voltages and currents from one value to another. In practice efficiencies of 98% may be achieved, the losses being due to heating effects of the transformer core, winding loss and leakage flux. Transformers have VA ratings which is simply the secondary voltage multiplied by secondary current -- this is strictly true only if the attached load is purely resistive (i.e. has a power factor of 1.0). A reactive load containing capacitors or inductors (which one would expect for such a power supply) has a low power factor (i.e. less that 1.0) and thus de-rates the transformer's power capacity to the stated VA multiplied by the power factor because it draws more current than a purely resistive load. So, when choosing a transformer for a reactive load, one needs to divide the load in watts by the load's power factor to arrive at the VA needed which has sufficient "headroom" to accommodate the low power factor. Not often published are the regulation figures for a typical transformer. A transformer rated at 20 V , 1 A secondary will only measure 20 volts when it is actually delivering 1 A. The figures below show typical regulation figures for some common VA rated transformers:-

VA Rating6122050100

% Regulation2512101010

For example a 12 VA rated transformer would have a no-load voltage which is 12% higher than the rated value. If the transformer was rated at 12 V @ 1 A, when measuring the secondary RMS voltage with a high impedance meter, you would measure approximately 13.44 Volts.

2.2AC Waveforms:

Before looking at rectification, some general information about AC wave forms. Figure 1 below shows two cycles of a sinusoidal waveform. The vertical axis shows amplitude and the peak to peak value (VPP), shown by the pink arrow is 20 Vpp. The peak value (VPK) is half the peak to peak value and is shown by the red arrow. The horizontal axis shows time.One complete sinusoidal cycle consists of a positive "peak" and a negative peak or "trough". One cycle is also 360 or 2 radians, a half cycle (VPKor -VPK) is 180 or in radians. Usually waveforms are displayed with horizontal axis in units of time.The waveform below shows two cycles each with a duration of 1ms. As frequency is the reciprocal of time, then this waveform has a frequency of 1 kHz.Figure 1

Value

Fig 2.1 two cycles of sinusoidal wave forms

The RMS or ROOT MEAN SQUARED value is the equivalent DC ( voltage or current ) which would provide the same energy to a circuit as DC voltage or current. In other words, if an AC sine wave has a value of 10 Volts RMS it will provide the same energy to a circuit as a DC supply of 10 volts.VRMS=VPKorVPK* 0.707

2

Average ValueThe AVERAGE value is normally taken to mean the average value of only half cycle of a sine wave. The average value of a complete sine wave is of course zero, as both halves are symmetrical about zero. Using only half a cycle, the average value (voltage or current) is always 0.637 of the peak value.VAVG=2* VPKorVPK* 0.637

Peak ValueThe Peak value of a sine wave is the maximum positive peak. Defined in terms of RMS voltage its value is:VPK= 2 * VRMSorVPK= 1.414 * VRMSPeak to Peak ValueThe peak to peak value, VPk is simply twice the peak value. The peak to peak value is the waveform that is displayed on an oscilloscope. RMS values are displayed by an AC multimeter.

Periodic TimeThe time taken for one complete sinusoidal cycle, (both positive and negative peaks) is known as the periodic time,(T). The frequency,(F) of the wave is the reciprocal of 1 cycle. Conversely, the reciprocal of frequency gives the periodic time.T =1orF =1

FT

Examples

2.3 Rectification unfiltered power supplies:

This is the process where alternating current is converted to direct current. Unfiltered, means that there is no smoothing capacitor present and the dc output will contain "ripples" at the line (mains) frequency. There are two types of rectification, half wave and full wave, also known as a bridge rectifier.R

The half wave rectifier circuit is shown in below:

RRRR 2

figf Fig 2.2 Half wave rectifier circuit

The DC output across a resistive load, is approximately the value of a half cycle, less one diode drop. Rectifier diodes have a forward voltage that varies from about 0.7V to 1.1 Volts in high current rectifiers. Conduction occurs for only one cycle, so is not very efficient, also without a smoothing capacitor, the output is quite "lumpy". Often these are used in cheap car battery charges where the quality of the supply is not too important.

A full wave rectifier circuit using a center tapped transformer is shown below in Figure 3. This circuit uses just two diodes each one conducting on alternate half cycles. The positive side is marked with a "+" and the output waveform shown in figure 5. Notice that the output ripple is now doubled.Figure 3 f or B Fig 2.3 full wave rectifier with center tapped transformer.The bridge rectifier is the most popular rectifier circuit. It uses four diodes arranged in a ring, but complete four terminal bridge rectifiers are also available. The circuit is shown in figure 4 below:Figure 4

Fig 2.4 full wave or bridge rectifier

There are twice the amount of "peaks" compared to the half wave rectifier because alternate diode pairs conduct for each half cycle of the AC input. A typical waveform is shown below figure

Figure 5

The blue trace is the peak to peak voltage of the transformers secondary winding, and the red trace is the unfiltered DC voltage. The DC output is approximately:1.41 x VRMS- (2 x 0.7)

2.4 Rectification filtered power supplies:

The "raw" DC produced after rectification is OK to charge a battery or light a lamp but any electronic circuit needs a smooth DC supply. In the case of audio circuits, particularly amplifiers, any unfiltered DC will be heard as a "hum" in the equipment's loudspeakers. The hum is proportional to the AC power supply's frequency. A filtered or smoothed supply is achieved by placing a large value electrolytic capacitor at the rectifiers output,

Figure 6

Fig 2.5 filtered power supply circuit diagram

The resulting waveforms are drawn in fig.2.6 below. The "brown" waveform represents the filtered DC feeding the load resistor.

Figure 7

Fig 2.6 filtered waveforms

Ripple Voltage

The rectifier diodes will charge up the filter capacitor, C1 to the peak DC value, and between non conducting cycles of the diodes, will discharge into the load resistor. This creates the saw tooth waveform known more commonly as ripple voltage. The value of the ripple voltage is dependent on load current, power supply frequency and capacitor value. Approximate ripple voltage is calculated using: V =I

2fC

where V is ripple voltage (mV), I is DC load current (mA), f is frequency of AC supply and C is smoothing capacitor value (F). V =10I

C

The bridge rectifier circuit above had a load current of about 191mA. Feeding this value into the first equation results in 191/(2 x 50 x 2200 e-6) =868.1 mV and the bottom equation (10x191)/2200=0.868V or 868mV.

2.5 Average DC Value:

The mean or average dc value is the value measured by a meter or multimeter. An oscilloscope shows the peak to peak waveforms and the oscilloscope horizontal cursor can be used to measure the dc value. The mean dc value for a full wave or half wave unregulated supply is difficult to predict because as the load current changes, so does the peak to peak ripple voltage.However with reference to below figure

h8

Fig 2.7 average dc waveforms

The mean or average dc value (shown in yellow) lies midway between the peak to peak ripple (shown as a blue dash line). For a half wave rectified supplies the average dc value is calculated by using VDC VPI

2Cf

For full wave or bridge rectified circuits the average dc voltage is calculated by:

VDC VPI

4Cf

VPis the peak voltage value (also the maximum ripple voltage), C is capacitance (F),I is load current(A) and f is the supply frequency(in Hz).

2.6 Diode Conduction and peak Diode Current:

This is not often seen but is illustrated with this small diagram below. It shows an output load voltage (in brown) with a little over 0.7 volts peak to peak ripple. It represents a full wave rectifier circuit with a 2200uF capacitor and two rectifier diodes, D1 and D2 have their current waveform superimposed onto the graph shown belowFi

9

Fig 2.8 diodes D1 & D2 wave forms

As can be seen, both diodes conduct rapidly on the leading edge of the ripple waveform charging the smoothing capacitor. D1 will charge the capacitor on the positive half of the input cycle, the capacitor then discharges through the load before the next half cycle where D2 will charge the smoothing capacitor and so on. The time interval T1 is the time each rectifier diode conducts The peak current through each rectifier is much higher than the load current and can be calculated with the following equation

Ipeak=T Idc

T1

Where:

RMST1=Diode conduction time

T=1/f f being line frequency

Idc=Average load current

Ipeak=Peak current through the rectifier

Load Regulation:Because the output voltage will drop, when any load current is drawn,load regulation is the term used to describe this fall. The load regulation of a power supply is defined as the percentage change in output voltage when the load current is increased from zero to full rated output.

3. LM35 HEAT SENSOR3.1 LM35 Description: LM35is a precision ICtemperature sensorwith its output proportional to the temperature (inoC). The sensor circuitry is sealed and therefore it is not subjected to oxidation and other processes. WithLM35, temperature can be measured more accurately than with a thermistor.It also possess low selfheating and does not cause more than 0.1oC temperature rise in still air. The operating temperature range is from -55C to 150C. The output voltage varies by 10mV in response to everyoC rise/fall in ambient temperature,i.e.,its scale factor is 0.01V/oC.

The LM35 is an integrated circuit sensor that can be used to measure temperature with an electrical output proportional to the temperature (inoC)

LM35s As a Measuring Temperature: You can measure temperature more accurately than a using a thermister. The sensor circuitry is sealed and not subject to oxidation, etc. The LM35 generates a higher output voltage than thermocouples and may not require that the output voltage be amplified. Pictorial Representation Of An LM35: Here it is.

Fig 3.1 pictorial representation of LM35

3.2 Working of LM35: Working Of An LM35: It has an output voltage that is proportional to the Celsius temperature. The scale factor is .01V/oC The LM35 does not require any external calibration or trimming and maintains an accuracy of +/-0.4oC at room temperature and +/- 0.8oC over a range of 0oC to +100oC. Another important characteristic of the LM35DZ is that it draws only 60 micro amps from its supply and possesses a low self-heating capability. The sensor self-heating causes less than 0.1oC temperature rise in still air.The LM35 comes in many different packages, including the following. TO-92 plastic transistor-like package, T0-46 metal can transistor-like package 8-lead surface mount SO-8 small outline package TO-202 package. 3.3 Using of an LM35: Here is a commonly used circuit. In this circuit, parameter values commonly used are: Vc= 4 to 30v 5V or 12 V are typical values used. Ra= Vc/10-6 Actually, it can range from 80 KWto 600 KW, but most just use 80 KW.

Connection of LM 35 wired on a circuit board. The white wire in the photo goes to the power supply. Both the resistor and the black wire go to ground. The output voltage is measured from the middle pin to ground l

LM 35 on circuit board

Fig 3.2 LM35 on circuit boardPin Diagram:

Fig 3.3LM35 pin diagramPin Description:

Pin NoFunctionName

1Supply voltage; 5V (+35V to -2V)Vcc

2Output voltage (+6V to -1V)Output

3Ground (0V)Ground

3.4 Advantages of LM35: Advantages of Use in LM35: Calibrated directly in Celsius(centigrade) The output voltage is converted to temperature by a simple conversion factor. The sensor has a sensitivity of 10mV /oC. Operating temperature range -55C to 150C Suitable for remote applications Low cost due to wafer level trimming Operates from 4V to 30V Low self- heating 0.08oC in still air. Low impedance output, 0.1 for 1mA load Less than 60 A current drain.

4.SEQUENTIAL SWITCHING IC LM 39144.1 IC LM 3914 description:LM3914 is a monolithic integrated circuit that senses analog voltage levels and drives 10 LEDs providing a linear analog display. A single pin changes the display from moving dot to a bar graph. Current drive to the LEDs is regulated and programmable, eliminating the need for resistors. This feature is one that allows operation of the whole system from less than 3V.

Fig 4.1 Pictorial representation of LM3914LM3914 Pin diagram

Fig 4.2 LM3914 pin description

4.2 LM3914 features: Drives LEDs, LCDs or vacuum fluorescents Bar or dot display mode externally selectable by user Expandable to displays of 100 steps Internal voltage reference from 1.2V to 12V Operates with single supply of less than 3V Inputs operate down to ground Output current programmable from 2 mA to 30 mA No multiplex switching or interaction between outputs Input withstands g35V without damage or false outputs LED driver outputs are current regulated, open-collectors Outputs can interface with TTL or CMOS logic The internal 10-step divider is floating and can be referenced to a wide range of voltages

4.3 LM 35 and LM3914 Interfacing Circuit Diagram:This temperature meter uses the precision micro power centigrade sensor IC LM35. The output voltage of the IC is linearly equal to 10Mv per degree centigrade. The temperature level is displayed through LED readout. The circuit uses the precision temperature IC LM35. This three pin transistor like IC give output linearly equal to10mV per degree rise in temperature. It can measure temperature between 4 degree to 110 degree centigrade. Its related type LM34 is Fahrenheit sensor and its output is equal to -10mV per degree Fahrenheit. Output of IC1 is directly given into the input of the display driver IC LM3914.It is a monolithic integrated circuit with 10 active low outputs that can drive 10 LEDs directly without a current limiting resistor.The internal circuitry of the IC adjusts the current passing through the LEDs. The input of LM 3914 is very sensitive and its outputs 18 10 sinks current one by one as the input receives an increment of125millivolts. Here only 6 outputs are used to drive 6 LEDs. More LEDs can be included in the remaining outputs if required. As the IC LM35 senses temperature rise, LEDs one to six light up. If the sensitivity is not high, VR2 can be omitted. Then output of IC1 should be directly connected to the input of IC2.

Temperature Meter Circuit diagram

Fig 4.3 LM35 and LM3914 interfacing circuit diagram

CalibrationWhen power is applied, some of the LEDs will glow. Calibrate the circuit by giving different temperature to IC1. For this a thermometer and hot water of different temperature is required. Sock some cotton with warm water of around 37degree (normal room temperature) and gently make contact with IC1. Adjust VR1and VR2, till LED1 glows.

5.Relay with Relay Driver5.1 Description of relay driver:

A relay driver circuit is a circuit which can drive, or operate, a relay so that it can function appropriately in a circuit.The driven relay can then operate as a switch in the circuit which can open or close, according to the needs of the circuit and its operation.Here both DC and AC relay drivers were build. Since DC and AC voltages operate differently, to build relay drivers for them requires slightly different setup. We will also go over a generic relay driver which can operate from either AC or DC voltage and operate both AC and DC relays.

Fig 5.1 Pictorial representation of Relay driver5.2 DC Relay Driver Circuit:To drive a DC relay, we require sufficient DC voltage which the relay is rated for and a zener diode.All relays come with a voltage rating. This is called on a relay's datasheet its rated coil voltage. This is the voltage needed in order for the relay to be able to operate and be able to open or close its switch in a circuit. In order for a relay to function, it must receive this voltage at its coil terminals. Thus, if a relay has a rated voltage of 9VDC, it must receive 9 volts of DC voltage to operate. So the most important thing a DC relay needs is its rated DC voltage. A diode is needed usually because it functions to eliminate voltage spikes from a relay circuit as the relay opens and closes. The coil of a relay acts an inductor. Inductors are basically coils of wires wrapped around a conductive core. This is what relay coils are as well. Therefore, they act as inductors. Inductors are electronic components that resist changes in current. Inductors do not like sudden changes in current. If the flow of current through a coil is suddenly interrupted, for example, a switch opening, the coil will respond by producing a sudden, very large voltage across its leads, causing a large surge of current through it. From a physics or physical perspective, this phenomenon is a result of a collapsing magnetic field within the coil as the current is terminated abruptly. Mathematically, this can be understood by noticing how a large change in current (dI/dt) affects the voltage across a coil (V=LdI/dt). Since we are opening the switch, in this case, the current literally goes from full mode to 0 instantaneously. This creates a large voltage spike. Surges in current that result from inductive effects can create very high voltage spikes (as high as 1000V) that can cause damage to the other components on the circuit board, such as switches and transistors getting zapped. Not only are these voltage spikes damaging to other electronic components in a circuit but they are also damaging to the relay's switch contacts. The contacts will suffer from these spikes as well.So for preventing these voltage spikes we are using diodes. A diode is placed reverse biased in parallel with the relay. The diode acts as a transient suppressor. A transient is a spike. A transient suppressor suppresses these spikes. Placing a diode in reverse bias across a relay's coil eliminates voltage spikes by going into conduction before a large voltage can form across the coil. In other words, a diode will conduct current in reverse bias once the voltage reaches a certain threshold and shunt the current to ground. Once the diode begins conducting, it no longer holds voltage. So that the relay in parallel will not receive the excess voltage. So the diode functions to shunt excess power to ground once it reaches a certain threshold. Diodes are devices that do not conduct in reverse. However, if the voltage reaches a certain level, called the breakdown voltage, it will conduct. This is a good thing, when we need the diode to act as a transient suppressor, because it forces all excess power to ground, as to not affect any other parts of the circuit.The diode must be rated to handle currents equivalent to the maximum current that would have been flowing through the coil before the supply current was interrupted. Therefore, if the relay normally passes a certain amount of current through it during normal operation, the diode must be rated for a current rating above this value, as to not stop normal operation.Components Needed DC Relay Zener Diode DC Voltage Source

Again, the DC relay must receive its rated voltage value in order to operate.The DC power source can be either batteries, wall wart power, or a DC power supply, any DC power source.The zener diode is placed reverse biased in parallel to the relay.

DC Relay Driver Circuit Schematic:

Fig 5.2 Dc relay driver circuit diagramThe relay which we use in this case is rated for 9V. Therefore, a 9-volt DC voltage source feeds the resistor. To suppress transients that may be caused by the relay opening and closing, we place a zener diode reverse biased in parallel with the relay. This will shunt all excess power to ground once it reaches a certain threshold. This is all that is needed to operate the relay. With sufficient power, the relay will now closed, driving the loads that are connected to its output.5.3 AC Relay Driver Circuit:This is a relay which is run, not off of DC power, but AC power.To drive an AC relay, all we need is sufficient AC voltage which the relay is rated for and again a transient suppressor.Unlike DC relays, however, we cannot use a diode to eliminate voltage spikes. With AC power, the diode will conduct on alternate half-cycles. Using 2 diodes in reverse parallel will also not work because the current will not make it to the coil of the relay. The current will just go through the diodes. Instead, to create a working transient voltage suppressor with an AC circuit, we use an RC series network placed across the coil in parallel. The capacitor absorbs excessive charge and the resistor helps to control the discharge.Components Needed AC relay 0.05F capacitor 100 Resistor AC Voltage Source

AC Relay Driver Circuit Schematic:

Fig 5.3 AC relay driver circuit diagramThe AC power switch circuit senses the presence of AC current in one outlet of a multi outlet power strip and switches power to the remaining outlets. It utilizes a current transformer, single transistor amplifier, voltage doubler detector, robust relay and capacitor limited AC power source. If we use a relay with a rated voltage of 110VAC, we must give an input of 110V from an AC power source. The capacitor and resistor in series acts as the transient voltage suppressor to suppress voltage spikes. This first half of the circuit serves as the relay driver. With the relay now having sufficient power, it will turn on and power the loads it is connected to.5.4 Generic Relay Driver Circuit:This is a relay driver circuit which can be driven by either AC or DC input voltage. And unlike the other circuits, a specific voltage, such as the rated voltage values we used to drive the others, does not need to be used. Because this circuit contains a transistor, much less power needs to used on the input side to drive it.Components Needed: 6-9V Relay 2N2222 Transistor Zener diode 1K Resistor 9V Battery or DC Power Supply Another input voltage source

Relay Driver Circuit:

The circuit is shown below:

Fig 5.4 Relay driver circuitHere transistor is used to drive the relay, we can use considerably less power to get the relay driven. Because a transistor is an amplifier, we just have to make sure that the base lead gets enough current to cause a larger current to flow from the emitter of the transistor to the collector. Once the base receives sufficient power, the transistor will conduct from emitter to collector and power the relay.With no voltage or input current applied to the transistor's base lead, the transistor's emitter-to-collector channel is open, hence blocking current flow through the relay's coil. However, if sufficient voltage and input current are applied to the base lead, the transistor's emitter-to-collector channel will open, allowing current to flow through the relay's coil.The benefit of this circuit is a smaller and arbitrary (DC or AC) current can be used to power the circuit and the relay.

6. UM3561 SIREN GENERATOR6.1 UM3561 description: UM3461 a an excellent ROM IC that can generate Multi siren tones simulating Police siren, Ambulance siren, fire brigade siren and machine gun sound. This 8 pin low power IC can work down to 2.4 volts The UM 3561 is a low cost siren generator designed for use in toy applications. The IC has an inbuilt oscillator and tone selection pins. It is easy to make a siren generator with only a few external components. Only one external resistor and a speaker driver transistor are sufficient to make a simple siren generator.Internal structure of UM3561: Inside the IC, there is an oscillator circuit and the frequency of oscillations is controlled by the external resistor connected to OSC 1(Pin 7) and OSC2 (Pin 8). A 220 K resistor will give the satisfactory results. The oscillations thus generated will be then transferred to a control circuit which function based on the tone selection through the connections of SEL 1 (Pin 6) and SEL2 (Pin 1) . The control circuit passes the signal to an address counter and then to the ROM. The tone pulses thus generated will be available from the output pin 3. Since the sound is weak, an amplifier is necessary to get loud sound. A single NPN transistor will amplify the sound.

Fig 6.1 Internal block diagram of UM35616.2 Pin diagram of UM3561:

Fig 6.2 Pin diagram of UM3561Pin AssignmentPin 1 Tone Sel.2Pin 2 GndPin 3 OutputPin 4 NC- Used for testing purposePin 5 +3VPin 6 Tone Sel .1Pin 7 Osc 1Pin 8 Osc 26.3 Tone Selection:By changing the pin connections of Sel.1 (Pin6) and Sel. 2(Pin 1) it is easy to change the siren tones.Sel 1Sel 2TonePin 6 Pin 1NC NC Police siren+3V NC Fire Engine soundGnd NC Ambulance SirenNC +3V Machine Gun soundCircuit diagram for tone selection:

Fig 6.3 circuit diagram for tone selection

WORKING:It has three main systems, 1) the detection system, 2) the monitoring system, 3) the appliance system. The detection system operates as the fire detector. The appliance system has components like buzzer for alarming and motor pump to stop the fire.The system detects the smoke, heat sensed by the detector. Finally when the sensors from each level triggered individually, the water flushes to the affected zone to stop the fire.Advantages:1. This project can be useful for automatic control of fire in many applications such as railways, shopping malls, hospitals, colleges, theaters etc.2. By this design we can control and monitor the study of fire.3. Reducing of fire accidents in different fields.Output:

We achieved 100% output what we planned in design.

FUTURE SCOPE:Fire accidents can be controlled to a great extent in a places such as forests, homes, colleges, industries, trains and some other public places. Fire accidents leads to death of excess of people, by using this technique we can save those lives easily.

The system can be modified with the use of graphical LCD panel so that the analysis is done by the system itself. The number of analog channels and Zeros can be increased to monitor more sensor outputs. We can even also combine the IR sensor, Light sensor, Smoke detector, pressure sensor, gas sensor with this project to make this project more efficiet.Conclusion:In this work an attempt has been done to control the fire accidents to save lives, as well as government property. It will help to reduce the percentage of fire accidents occurring indifferent fields.The present model with some of the changes in outputs and sensing we can apply to real time process.

REFERENCES:1.IEEE standard notes.2. Internet.

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