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Solar Tracker

Build a Sun-Tracking Solar Panel!!

Use

an

Arduino

Pro

Mini,

a

standard

servo,

some

clever

machining,

and

some

photoresistorvoltagedividerstobuildaoneaxisSunTrackingSolarPanel

TheSolarTrackeraimsatmaximizingsolarenergyabsorptionthroughouttheday

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Step 1 Get supplies

You Will Need:

4

x

Photo

Resistors

I

use

4

but

this

could

be

done

with

2

and

better

logic4xResistors willbesizeddependingonphotoresistors

1xArduinoProMini3285v

x a e

1xStandardServo

1

x

Random

Servo

Hardware1xAcr licInch8x3inSheet

1xRollofElectricalTape

1xMiniBreadboard

1xAluminumLShapedMaterial(4x4x6inchsides)

1xSolarPanel

2xIndustrialStrengthVelcro

2xScrewsandNuts3/4inch440thread

8xScrewsandnuts1/2inch440thread

Solder

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Step 2 Tools needed

You Will Need (Power Tools):

Miter

sawSteelimpregnatedpowersander

Drillpresswith1/8inchbits

or zonta an saw

You Will Need (Hand Tools):Assortedfiles

Deburringtool

Adjustablewrench

Soldertool

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Step 3 Project Mount

L-Bracket

Cut

the

L

Bracket

into

a

6inch

length

or

so.

Use

the

sander

to

smooth

it

all

outInthecenterofoneoftheplanes,markanddrilltwoholes.Usesanderandde

burr

Side Back

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Step 3 Project Mount

Servo to L-Bracket Connector

Mountservohardwaretothe1x8inchshank

Takeyourshank,selectheight,markholesfromLBracketanddrill

Rememberthatthesolarpanelwillberotatingalongtheservosaxis soleave

appropr ateroom. an an e urr

Assemble

Servo

hardware

Side Back

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Step 4 Sensor Array

Cant Adapt without them:

Usetheohmmetertomeasuretheresistivityofthephotoresistorsbothinadark

andinasunnyarea.Thenuseavoltagedividertodeterminethemostaccurate

scopebymaximizingthevoltagechangebetweentheresistors

Photo+5v 0V

Maximize the

change inthis voltage

ccResistor

es s or roun

FromTestingDark 12000Ohm (Fingeroverphotoresistor)Ambient 1100Ohm (Classroom)

SimulatedSun 78Ohm (12inchesfrombrightworklight)

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Step 4 Sensor Array

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Step 4 Sensor Array

Results

Goinginseries (VccpRRGND)tiethepRRnodetotheADC

pinmaxo p no e sa out . an m n sa out .

UseRof1kand+/10%willkeepdifferenceingreatestregion

Allresistors

are

0.98xkOhmswhichiswithinstandardsand

willcreatesimilarreadablevoltages

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Step 4 Sensor Array

Build the Servo Array:

Weregoingtouse4sensors.Getoutthatsolderingironandusethisschematic

Usetheelectricaltapetocoveranyexposedwiring

Testwithapowersourceandohmmeter

Photo

Resistor

Resistor

GNDADCVCC

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Step 4 Sensor Array

Assemble the Array:

Takethefoursensorsandattachthemtotheassembledprojectmountandsolar

assembly

Takesomeextrawireandelectricaltapeandbuildsolarblindersforthesensors

e n ersa ow or etterca rat onan sens ng

Servo

Side Front

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Step 5 Microcontroller

Get your program on

SolderleadstoyourArduino

GettheFTDIcableinstalledandfunctional

UploadatestprogramtotheArduino(verifyfunctionality) Arduino Pro Miniarduino.cc

ttac oursensorsto s ana ogto g ta convers on

AttachservotooneofthePWM(pulsewidthmodulation)ports

UsetheUARTtocheckvaluesofADCreadingsthroughSerial.println(sdfsdf);

UsetheServoclasstoinitializeandtest ourservo

Setupaninitializationroutinewheretheservomovesthesolarpanelsothe

sensorarraycandeterminetheangleofmaximumsunlightandthenmovethere

Setuptrackinglogic.Iusedaminimumofa10%differencebetweenanytwo

.

reducesoscillationsduetonoise.

Withfoursensors,thepanelcanmoveinsmallamounts(differencebetweenthe

centerlookingsensors)orlargeamounts(ifthesideviewsensorsindicatealarge

differential)

Becarefulwithcastingandscaling.

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Step 5 Microcontroller

Program more

CloudModeIfcloudsarepresentorthedayisovercast,youcanlookattherate

thesunhasbeenmovingandassoonasitappearsagainmovedirectlytothemaximumangle

Nightmode IfthedeviceisinCloudModeforalongwhileandthepanelis

facingthesettingsun,youcanimplementanotherpredictivecasewherethepanel

caneitherbemovedparalleltothegroundorreflectedacrosstheverticalaxisto

.

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Step 6 Testing

Attach the Solar Panel and Increase Efficiency!

Setupavoltagedividersimilartothesensorsandattachthesolarpaneltooneof

theunusedADCs

Watchthevoltagechangeinproportiontotheangleofthesolarpanel

Isthesystemreallyworthit?Grabacouplemorestationarysolarpanels,build

somemorevoltagedividers,attachtotheADCs,andlookatthedifferencesovera

fewweekperiod.Youbethejudge!

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Sources

Give Credit

fromhttp://arduino.cc/en/Reference/Libraries

servolibrary,andcorrespondingexamplecode Arduino Pro Miniarduino.cc

y, o o x o

variablecastinghttp://www.mkssoftware.com/docs/man3/itoa.3.asp