Basil Final

8/8/2019 Basil Final

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MICROCONTROLLERMICROCONTROLLER--

BASEDBASED

SPEEDOMETERSPEEDOMETER--CUMCUM--

ODOMETERODOMETER

Submitted bySubmitted by

BABY BESTINBABY BESTINBASILJOHNSONBASILJOHNSON

THARA VIJAYANTHARA VIJAYAN


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INTRODUCTIONINTRODUCTION

TheThe projectproject comprisescomprises aa dcdc motor motor speedspeed

controllercontroller circuitcircuit withwith reedreed sensorsensor.. ItIt isis beingbeingdetecteddetected byby thisthis andand displaydisplay thethe samesame atat LCDLCD

inin formform ofof speedspeed KmKm../Hr/Hr.. andand alsoalso displaydisplay thethe

distancedistance coveredcovered byby thethe vehiclevehicle..


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FEATURES OF DIGITALFEATURES OF DIGITAL

SPEDOMETERSPEDOMETER

Digital readoutDigital readout

Speed displayed in km/hourSpeed displayed in km/hour

Distance traveled displayed in kilometersDistance traveled displayed in kilometers

Readings saved in nonReadings saved in non--volatile memory (EEPROM)volatile memory (EEPROM) Reliability due to use of the microcontrollerReliability due to use of the microcontroller

No mechanical wear and tearNo mechanical wear and tear

HomeHome--brewed speed transducer/ sensorbrewed speed transducer/ sensor

Self reset to zero after completion of 99,999.9 kmSelf reset to zero after completion of 99,999.9 km Easy to build and fix onto the bikeEasy to build and fix onto the bike


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BLOCK DIAGRAMBLOCK DIAGRAM


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SPEEDOMETER-CUM-

ODOMETER UNIT ON A BIKES

HANDLE BAR


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REED SWITCH AND MAGNET

FIXED ON THE FRONT WHEEL

OF MOTOR BIKE


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CIRCUIT DIAGRAMCIRCUIT DIAGRAM


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CIRCUIT COMPONENTSCIRCUIT COMPONENTS

PIC 16F873APIC 16F873A

LCD MODULE

SPEED SENSOR OPTOCOUPLEROPTOCOUPLER

POWER SUPPLYPOWER SUPPLY


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CIRCUIT DISCRIPTIONCIRCUIT DISCRIPTION

PIC16F873APIC16F873A

Parameter NameParameter Name ValueValue

Program Memory TypeProgram Memory Type FlashFlash

Program Memory (KB)Program Memory (KB) 77

CPU Speed (MIPS)CPU Speed (MIPS) 55 RAM BytesRAM Bytes 192192

Data EEPROM (bytes)Data EEPROM (bytes) 128128

Digital Communication PeripheralsDigital Communication Peripherals 11--A/E/USART, 1A/E/USART, 1--

MSSP(SPI/I2C) Capture/Compare/PWM PeripheralsMSSP(SPI/I2C) Capture/Compare/PWM Peripherals 2 CCP2 CCP

TimersTimers 2 x 82 x 8--bit, 1 x 16bit, 1 x 16--bitbit ADCADC 55 chch, 10, 10--bitbit

ComparatorsComparators 22

Temperature Range (C)Temperature Range (C) --40 to 12540 to 125

Operating Voltage Range (V)Operating Voltage Range (V) 2 to 5.52 to 5.5

Pin CountPin Count 2828


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LCD MODULELCD MODULE

To display the speed and distance traveled, weTo display the speed and distance traveled, we

have used a 16x2 alpha numeric LCD based onhave used a 16x2 alpha numeric LCD based onHD44780 controller. The backlight feature ofHD44780 controller. The backlight feature of

the LCD allows data to be visible even at nightthe LCD allows data to be visible even at night


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SPEED SENSOR.

For this project, we make use of a simpleFor this project, we make use of a simple

homehome--made speed transducer. The rotation ofmade speed transducer. The rotation ofthe wheel is sensed by the combined action ofthe wheel is sensed by the combined action of

a reed switch and a magnet fixed on the wheel.a reed switch and a magnet fixed on the wheel.

The sensor sends a pulse to the microcontrollerThe sensor sends a pulse to the microcontroller

each time a revolution is madeeach time a revolution is made


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OPTOCOUPLER.

An optocoupler is used to counter the effects ofAn optocoupler is used to counter the effects of

bouncing when the contact of reed switch isbouncing when the contact of reed switch isclosed.closed.


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POWER SUPPLY.POWER SUPPLY.

The power supply for various parts of theThe power supply for various parts of the

circuit is drawn from the vehicles 12V batterycircuit is drawn from the vehicles 12V batteryafter reducing it to 5V using a threeafter reducing it to 5V using a three--terminalterminal

voltage.voltage.


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WORKINGWORKING

ReedReed switch,switch, whichwhich isis aa electroelectro mechanicalmechanical switchswitch ,,

whenwhen comescomes inin contactcontact withwith thethe magnet,magnet, getsgets closedclosed..

AsAs aa resultresult optocoupler,optocoupler, whichwhich interfacesinterfaces reedreed switchswitch

withwith thethe PICPIC microcontrollermicrocontroller getsgets activatedactivated resultingresultinganan interruptinterrupt signalsignal toto thethe microcontrollermicrocontroller.. NumberNumber ofof

interruptsinterrupts multipliedmultiplied withwith thethe perimeterperimeter ofof thethe wheelwheel

providesprovides thethe distancedistance coveredcovered.. AndAnd thethe numbernumber ofof

interruptsinterrupts withwith inin aa particularparticular timetime givesgives thethe speedspeed..

DistanceDistance andand speedspeed areare shownshown inin thethe LCDLCD displaydisplay


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CALCULATIONCALCULATION

Circumference of the wheel= 2rCircumference of the wheel= 2r

(where r is in cm)(where r is in cm)

= 2= 23.143.143030

= 188.4 cm or 1.884 metres= 188.4 cm or 1.884 metres

Speed in km/hour:Speed in km/hour:

NN1.881.883600/10003600/1000

= N= N6.784 or N6.784 or N6.86.8

Distance :Distance :

The odometer is updated every 100 metres. To cover 100 metres,

the wheel is required to make approximately 53 revolutions

(100/1.88).


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CONCLUSIONCONCLUSION

Normally,Normally, digitaldigital speedometersspeedometers areare foundfound onlyonly inin luxuryluxury

carscars andand highhigh--endend motorbikesmotorbikes.. EvenEven ifif youryour motorbikemotorbike

hashas aa mechanicalmechanical speedometer,speedometer, whatwhat willwill youyou dodo whenwhen

itit getsgets damaged?damaged? First,First, youyou needneed toto replacereplace thethemechanicalmechanical wormworm geargear andand thenthen thethe cablecable..


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REFERENCEREFERENCE

Electronics for you . November 2008Electronics for you . November 2008 http://www.wikipedia.org/http://www.wikipedia.org/


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Basil Final

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