101

Arm and Gripper Overview

Preparation:•Cleartheworkstation.•OrganizetheTETRIX®andMINDSTORMS®sets.

•ChargetheTETRIXandNXTbatteries.

Materials: •CompletedRangerBotfromLesson3

•TETRIXEducationBaseSet(739143)•LEGO®MINDSTORMS®EducationNXTBaseSet(W979797)

•Software(ROBOTC®orLabVIEW™forLEGOMINDSTORMS)installedoneachcomputer

Resources:•EngineeringJournalWorksheet•ArmandGripperExtensionOverview

•ArmandGripperExtensionBuildingGuide

•ArmandGripperExtensionProgrammingGuide

•ArmandGripperExtensionReferenceGuide

•ArmandGripperExtensionSampleProgram

•Arm and Gripper Extension – How It Should Workvideo

•ArmandGripperExtension3-DModel

Building Objectives:•LearnhowtowireandattachaTETRIXServoMotor.

•IntegrateaMINDSTORMStouchsensorintoaMINDSTORMSwithTETRIXrobot.

Programming Objectives:•LearnhowtoprogramaTETRIXServoMotorinordertopickupandplaceanobject.

•Usesensorinputstosenseobjectsandnavigatetherobot.

Best Practices:BesuretoreviewtheGeneralBestPracticesGuideintheIntroductionsectionoftheTETRIXGettingStartedGuide.

Building

•UsethesmallblackscrewtosecurethehornontheServoMotor.•Useabronzebushinganytimeanaxleisused.•Useaxlespacerstokeepcomponentsinplaceandcorrectlyaligned.

Programming

•Becarefulwhensettingtheopen/closevaluesfortheservo.Itshouldopenfarenoughtofitaroundanobjectandclosetightlyenoughtosecurelyholdtheobject.

•NotethattheWaitfunctionusesmilliseconds.•Notethatfordebuggingpurposes,theNXTBrickdisplaysthesensorvalueswhenrunningtheprovidedsampleprograms.

•Becausedifferentsensorsmayhavedifferentvaluesforthesameobjects,thethresholdvaluesoftheultrasonicsensorandthelightsensormayneedtobechangedandtested.

•Thresholdvaluesfortheservosmayrequiresomeadjustment,dependingonthealignmentandthepositionoftheservo.

Programming (LabVIEW for LEGO MINDSTORMS)

•Makesurethattheportsusedintheprogramcorrespondwiththeschematiceditor.Formoreinformation,consulttheSchematicEditorGuideontheTETRIXGettingStartedGuideDVD.

•Trytokeepthecodelinearandwellorganized.Thismakesthecodemucheasiertofollowanddebug.

Inthisextension,anarmandgripperwillbeassembledandattachedtotheRangerBot.TheRangerBotwillbeprogrammedtofollowaline,pickupacup,andputthecupinabox.

Estimated Time: 90minutes

TETRIX®GettingStartedGuideExtensions