01-11-2016, 09:57 AM
AN INTELLIGENT DENSITY BASED TRAFFIC LIGHT CONTROL USING IR SENSORS AND RF TECHNOLOGY
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As the number of road users constantly increases, and resources provided by current infrastructures are limited, intelligent control of traffic will become a very important issue in the future. There are several models for traffic simulation. In our research we focus on optimization of traffic light controller in a city using IR sensor and devel-oped visual monitoring using microcontroller LPC2148. Traffic light optimization is a complex problem. Even for single junctions there might be no obvious optimal solution. With multiple junctions, the problem becomes even more complex, as the state of one light influences the flow of traf-fic towards many other light. An embedded system is a special-purpose system in which the compute is completely encapsulated by or dedicated to the device or system it controls. Embedded systems are often mass-produced, benefiting from economies of scale.
The project may be very well used in where the traffic signals is kept and in many other places where we need to full fill the need of the automation. This project is very useful in heavy traffic areas. This project decreases the manual effort to a large extent, thus making the traffic management much more easier than before.
The systemisbasedonmicrocontroller.The microcontrollerusedinthesystemis LPC2148whichisARM7family based.ThesystemcontainsIRtransmitterandIR receiver whicharemounted on the either sides of roads respectively.
Thepowersupply isswitchedon.Thenthepowerissuppliedtothedifferent components of thesystem. Themicrocontroller acts as the main component of the project. TheIRsystemgetsactivatedwheneveranyvehiclepassesonroadbetweenIRtransmitter andIRreceiver.Microcontroller controlstheIRsystemandcountsnumber of vehicles passing onroad.Basedondifferentvehiclesdensity,themicrocontrollertakesdecision and updates thetraffic light delaysas a result.
The traffic lightissituatedata certaindistance fromtheIR system.Thusbasedon vehicle density, microcontroller defines different ranges for traffic light delays and updatesthose accordingly.Thesystem recordstrafficdensityin itsmemoryatuser predefinedrecordingintervalonrealtimebasis.Thisrecordedtrafficdensity canbeused in futureto analyzetraffic condition at respectivetraffic lights connected to the system.
Forappropriate analysis,therecordeddatacanbe transferredtoprevioustraffic junctiontoavoidthetraffic jams.Ifthetrafficisclearedaftersometime,thestatusofthe samewillbe informedtopreviousstopsagainthroughRF modules.Infuture this system can beusedto inform people about different places traffic condition.
The Hardware components used in project are :
Powersupply:
The powersupplies are designedto converthighvoltage ACmains electricityto a suitable lowvoltagesupply forelectroniccircuitsandotherdevices.Apowersupply canby brokendown into aseriesofblocks,eachofwhichperformsaparticularfunction. AD.Cpowersupply which maintainstheoutputvoltageconstantirrespectiveof A.Cmainsfluctuationsorloadvariationsis known as“Regulated D.CPowerSupply”.
Dual Supplies:
Some electroniccircuits requireapowersupplywith positive and negativeoutputs aswellas zero volts(0V).Thisiscalleda'dualsupply'because itislike twoordinary supplies connected together as shown in thediagram.
Dualsupplieshavethreeoutputs,forexamplea±9Vsupply has+9V,0Vand-9V
outputs.
Transformeronly:
ThelowvoltageACoutputissuitableforlamps,heatersandspecialACmotors. Itisnotsuitableforelectroniccircuitsunlessthey includearectifierandasmoothing capacitor.
Transformer:
Atransformerisanelectricaldevicewhichisusedtoconvertelectricalpower from one electricalcircuit to anotherwithoutchangein frequency.
Transformersconvert ACelectricity fromonevoltagetoanotherwithlittlelossof power.Transformersworkonly withACandthisisoneofthereasonswhy mains electricityis AC. Step-uptransformers increaseinoutputvoltage, step-down transformers decreaseinoutputvoltage.Mostpowersuppliesuseastep-downtransformertoreduce thedangerouslyhighmainsvoltagetoasaferlowvoltage.Theinputcoiliscalledthe
primary andtheoutputcoiliscalledthesecondary.Thereisnoelectricalconnection betweenthetwocoils;insteadthey arelinked by analternatingmagnetic fieldcreatedin thesoft-ironcoreofthetransformer.Thetwolinesinthemiddleofthe circuitsymbol representthecore. Transformerswastevery littlepowersothepoweroutis(almost) equal to the power in. Note that as voltageis stepped down current is stepped up.
Theratioofthenumberofturnsoneachcoil,calledtheturn’sratio,determines theratioof thevoltages.Astep-downtransformer hasa large numberof turnsonits primary (input)coilwhichisconnectedtothehighvoltagemainssupply,andasmall numberof turns on its secondary(output)coilto givealow outputvoltage.
RECTIFIER:
AcircuitwhichisusedtoconvertA.CtoD.CisknownasRECTIFIER.The
process ofconversion A.C to D.C is called “rectification”
Types ofrectifiers:
1. Half waveRectifier
2. Fullwaverectifier
a) Centretap fullwave rectifier.
b)Bridgetypefull bridge rectifier.
REGULATOR:
Voltage regulatorICs isavailable with fixed (typically5, 12and 15V)or variable outputvoltages. Themaximum current theycan pass also rates them. Negativevoltage regulators areavailable,mainlyforusein dual supplies. Most regulators include some automaticprotection from excessive current.
Manyof the fixed voltage regulatorICs has 3 leads andlook like power
transistors, such as the 7805 +5V 1Aregulator shown on the right. TheLM7805 is simple to use.
You simplyconnect thepositivelead ofyour unregulated DC power supply (anything from 9VDC to24VDC) to theInput pin, connect thenegativelead to the Common pin and then whenyou turn onthe power,youget a 5 volt supplyfrom the outputpin.
LPC2148MICROCONTROLLER :
.ARM is theindustry's leading provider of32-bit embedded microprocessors, offeringawide rangeofprocessorsbasedonacommonarchitecture thatdeliverhigh performance, industryleading power efficiency and reduced system cost. Combined with the broadestecosystem intheindustrywithover900Partnersdeliveringsilicon, toolsandsoftware,thewide portfolioof more than20processorsare abletomeetevery applicationchallenge.Withmorethan25billion processorsalready createdandinexcess of16 million shipped everyday.
Itisworthwhiletogooverthisconceptsince RISCisimpliedinthename!Italso lendsitselftothediscussionofwheresomeofthehardwarechoices,aswellasclaims that aremadeon this typeof processor's performance, came from.
1. RISCisanacronymstandingfor"ReducedInstructionSetComputer",contrasted with a CISC machine(ComplexInstruction Set Computer).
2. RISC claims of simplicityin comparison to CISC.
3. Fixed 32-bitinstruction sizeinstead of variable
4. Largeregister bank of GPR 32-bitregister
5. Easierto prototype and put together
6. RISC Organization.
7. Hard-wired instruction decodelogic instead of micro coded ROMs to decode
8. Pipelined execution
9. Possible single cycleexecution
10.RISC Advantages
11.Smallerdie sizes
12.Shorter timeto develop
13.Possible higher performancethan CISC
14.High clock ratewith singlecycle
15.RISC Disadvantages
16.Generallylesscodedensitythan CISC
17.Cannot execute x86 code, at least not without some sort of conversion and performancedrawback.