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2002 LEGO, LEGO Educational Division, LEGO Mindstorms for Schools, and

ROBOLAB are trademarks of the LEGO Group. This page may be photocopied for non-commercial educational use.All other rights reserved.

Visit www.lego.com/education & www.legoengineering.com

RRROOOBBBOOOLLLAAABBBRRReeefffeeerrreeennnccceee

GGGuuuiiidddeeeVVVeeerrrsssiiiooonnn 111...444


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Preface: Getting Help with ROBOLABROBOLAB is a growing application for which users canreceive support in many different ways. Embedded inROBOLAB are context help and extended help information andexamples. A PDF is available on the ROBOLAB CD that focuseson teaching readers how to use different components of thesoftware.

Several books have been written that focus on tips andtricks for using ROBOLAB and LEGO bricks and accompanyingactivities for use with students. These books includePhysics by Design by Barbara Bratzel(http://www.collegehousebooks.com/physics_by_design.htm)and Engineering with LEGO Bricks and ROBOLAB by Eric L.

Wang (http://www.collegehousebooks.com/lego_bricks.htm).

Carnegie Mellons Robotic Institute has developedadditional support. Their NXT Mobile Robotics Curriculumand NXT Engineering Projects Curriculum is available atfrom your LEGO Education distributor.

The web also serves as a means of finding information, newcapabilities, suggested ways to use the software, classroomcurriculum, and additional tutorials on using ROBOLAB. Theweb component is a continually growing environment where we

update and add new material and sample curriculum all thetime.

This guide is designed to serve as an extended referenceresource for the ROBOLAB software. It aims to supplementthe other support and help components that already exist.With nearly 300 pages of information, the ROBOLAB ReferenceGuide is best used as an interactive electronic documentfrom which pages or sections can be printed if needed. TheGuide is a dynamic project, continually growing and beingupdated. The most current version is available for downloadat www.legoengineering.com.

2002 LEGO, LEGO Educational Division, LEGO Mindstorms for Schools, andROBOLAB are trademarks of the LEGO Group. This page may be photocopied for non-commercial educational use.

All other rights reserved.Visit www.lego.com/education & www.legoengineering.com
http://www.collegehousebooks.com/physics_by_design.htmhttp://www.collegehousebooks.com/lego_bricks.htmhttp://www.collegehousebooks.com/lego_bricks.htmhttp://www.collegehousebooks.com/physics_by_design.htm


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Help in ROBOLABThe first place to look for help is within ROBOLAB. Allversions of ROBOLAB have context help for the softwareenvironment. Help can be turned on and off using the HelpButton or via keyboard shortcuts (CTRL-H)

Context HelpBox

Help Button

After turning on the help, placing your mouse over anyobject in a window or icon the context help will present adescription of the item or directions on how to use it.This type of help can be useful for learning how to use theAdministrator, Pilot, or Investigator sections of ROBOLAB.




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The Clihere formore hellink

When programming in Inventor or higher levels ofInvestigator, context help is also available for each ofthe icons. This help that comes up describes thefunctionality of the command, default settings, and theelements of it that can be modified. In ROBOLAB 2.5 andhigher, the Click here for more help link appears in theContext Help window. This brings up extended helpinformation and a sample program that uses the command(that can be opened and downloaded). The extended help

allows the user to see examples.

The Using ROBOLAB guideFor a more detailed introduction to using the software,step by step directions, and more examples and challenges,the Using ROBOLAB guideis very useful. This PDF isavailable through your LEGO Education distributor or inelectronic (pdf) format at www.legoengineering.com.

Topics in the Users Manual Include

The Pilot and Inventor levels of programming in thePROGRAMMER component of ROBOLAB. This is all one needsto program a LEGO robot.




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The INVESTIGATOR component that is used for data logging.This section adds scientific investigation to therobots capabilities, allowing the RCX to become asmart and mobile data logging tool. The Investigator

component also includes a Journal Area for documentinga project in text and photographs or illustrations anda Publish feature for sharing results.

The enhanced Media features: the Piano Player and Cameraavailable in ROBOLAB 2.5.1 and higher. The manual alsoshows how to use some of the higher level capabilitiesincluding Vision Center and subroutines.




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ROBOLAB Web SitesROBOLAB has a growing web based community that hasinformation, ideas, and examples of users in action. Two

web sites that have learning resources, developerinformation and SDKs, new downloads, more documentation andsupport are:

http://www.legoengineering.com

and

http://www.lego.com/education

These sites are a great place to visit for up to the minutepatches, new features, additions, and tutorials. Both sitesalso maintain a large number of links to curriculumresources, activity databases, and information on classroommaterials. The Lego Users Group Network (LUGNET) atwww.lugnet.com (not officially supported by LEGO) alsoprovides a great resource for discussing ROBOLAB and otherLEGO issues and locating additional information.


http://www.legoengineering.com/http://www.lego.com/educationhttp://www.lugnet.com/http://www.lugnet.com/http://www.lego.com/educationhttp://www.legoengineering.com/


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TABLE OF CONTENTSPreface: Getting Help with ROBOLAB ........................ 2Help in ROBOLAB ......................................... 3ROBOLAB Web Sites ....................................... 6

TABLE OF CONTENTS ......................................... 71. About ROBOLAB .......................................... 91. About ROBOLAB .......................................... 9Low Entry --High Ceiling ................................ 9ROBOLAB and LabVIEW .................................... 10

2. Programming Icons and Examples ........................ 15Basic Outputs .......................................... 16Behaviors .............................................. 28Wait Fors .............................................. 39Tasks & Subroutines (Structures) ....................... 67

Forks .................................................. 71Jumps ................................................. 102Loops ................................................. 105Events ................................................ 133Task Priority ......................................... 171Music ................................................. 172Investigator .......................................... 176Reset ................................................. 198Containers ............................................ 212RCX Communications .................................... 255Modifiers ............................................. 264

Direct Functions ...................................... 295Internet .............................................. 300Advanced .............................................. 302Control Lab Interface ................................. 305NXT Commands .......................................... 310G-Code ................................................ 326Multimedia ............................................ 345

3. How To .............................................. 3583.1 Using Vision Sensors Outside of Vision Center ..... 3593.2 Containers in ROBOLAB ............................. 3633.3 User Data in ROBOLAB .............................. 364

4. Customizing ROBOLAB .................................. 3664.1 Editing the Default.prf file ...................... 3674.2 Creating your own Sensor Definition Files ......... 3724.3 Customizing Investigator .......................... 378

5. Help & Idea Sources .................................. 384Appendix ................................................ 387




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Troubleshooting Programming Problems .................. 388Tips and Tricks ....................................... 394Related Web Sites and Resources ....................... 397

Acknowledgements ........................................ 398Index ................................................... 399




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1. About ROBOLABROBOLAB is the software that provides the tools andenvironment for programming, creating, learning andexploring with the LEGO RCX and NXT. With an intuitive,graphical interface, students of all ages are able tocreate autonomous robotic creations, collect data, composemusic, and snap pictures.

The RCX & NXT The Programmable LEGO Bricks

Low Entry --High CeilingLEGO elements can be a powerful teaching tool for studentsof all ages. Using LEGO bricks a kindergarten student canexplore the concept of numbers and sorting. Add a fewmotors and sensors to those LEGO bricks and a collegestudent can learn about engineering and physics by buildinga robot or a set-up to measure spring constants. Having

students from 5 - 25 use the same toolset to learn allowsmore time to be focused on learning and exploring and lesson learning how to use software.




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ROBOLAB and LabVIEWROBOLAB is built on top of a robust piece of software

called LabVIEW. LabVIEW is a powerful programmingenvironment used by engineers and scientists in collegesand industry. It is the leading software development toolfor measurement and control. Created by NationalInstruments (Texas, US) in 1997, LabVIEW is used to analyzeand compute real results for biomedical, aerospace, energyresearch applications and numerous other applications.NASA, for example, monitored the Mars Sojourner Rover'slocation and position in relation to the landing craft, itsorientation to the ground, its overall physical health andmore using LabVIEW.

LabVIEW is a graphical programming development environmentthat allows scientists and engineers to write programs andcreate user interfaces. A basic LabVIEW program, called avirtual instrument (vi) has 2 components to it a frontpanel and a diagram. The front panel is where standarduser interface options like buttons, dials, and graphs aredisplayed.




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Run Button

A Simple LabVIEW Front Panel

The simple LabVIEW front panel for the vi,addtwonumbers.vi, above allows the user to enter twonumbers (Number 1 and Number 2) when the program isexecuted by pressing the run button. What happens when therun button is pressed is defined in the diagram. Thediagram defines the logic and operations of the vi (LabVIEWprogram).




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A Simple LabVIEW Diagram

The diagram above takes Number 1 and Number 2 and adds themtogether and displays the result in Answer.Addtwonumbers.vi is an overly simple example of LabVIEWs

capabilities but helps to demonstrate the graphicalinterface and basic concepts.

ROBOLAB makes use of LabVIEWs capabilities and interfacein several ways. LabVIEWs intuitive graphical interfacemakes it easy for the developers of ROBOLAB to programquickly and easily. All the customized screens andtemplates, including the Administrator, the Pilot Levels,Investigator, Vision Center, and Piano Player are LabVIEWfront panels. Behind those front panels are diagrams thatcontain the complicated programming that provides their

functionality.




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The Pilot 1 Front Panel

The Pilot 1 Diagram




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At the Inventor Level and the higher programming levels ofInvestigator, users are actually doing modified LabVIEWprogramming. The bottom purple window that appears isactually a LabVIEW diagram.

FrontPanel

Diagram

When the run button is pressed, the code is compiled andsent to the RCX or NXT. A window will pop-up asking if youare using the RCX, the NXT, or theControl Lab? The

majority of ROBOLAB programming doesnt require the frontpanel so it is presented in a smaller format and used todisplay additional directions and information (like theWelcome to Inventor message).

The similarities between the upper levels of ROBOLAB andLabVIEW mean that ROBOLAB users have much of the power ofLabVIEW at their disposal allowing them to perform nearlyany task or challenge they can conceive. It also meansthat users who wish to go further with programming have asolid foundation in this type of graphical programming

environment and can easily transition to using LabVIEW.




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2. Programming Icons and ExamplesThis chapter provides additional hints and example programsfor all of the ROBOLAB icons (excluding a few higher levelpalettes). The examples can also be accessed through theextended help in ROBOLAB 2.5 and higher (using the Clickhere for more help link in the Help Window). The sectionswere created using the highest, most comprehensive level ofROBOLAB (Investigator Program Level 5). Hence, if youare using lower levels of Inventor or Investigator some ofthe icons listed may not appear on your Functions Palette.




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Basic Outputs

BeginAlways start an Inventor program with thiscommand.

Example

This piece of code would turn on motor A for one second and

then turn it off.

EndAlways end an Inventor program with this command.Each task will need its own end command.

Example

This piece of code would turn on motor A for one second andthen turn it off.




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Motor AForward

Motor AReverse

Motor BForward

Motor BReverse

Motor CForward

Motor CReverse

Use this if you have a motor connected to port A, B,or C that will be spinning in the forward or reversedirection. Use the power level modifier to change howfast the motor spins, from 1 (slow) to 5 (fast).Without a modifier, the power level will be 5 (fast).

Example

This piece of code would turn on motor A in the forwarddirection for one second and then turn it off.

Lamp A Lamp B Lamp C

Use this if you want the lamps connected to port A, B,or C to turn on. Use the power level modifier tochange it from bright (5) to dim (1). Without amodifier, the power level will be 5 (bright).

Example

This piece of code would turn on the lamp connected to portA for one second and then turn it off.




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Stop A Stop B Stop C Stop allOutputs

Use this to stop the motor or lamp connected to portsA, B, and C by braking (abrupt stop). To get a moregradual stop, use the float command.

Example

This piece of code would turn on the lamp connected to port

A for one second and then turn it off.

PlaySoundUse this command to get an audio response fromthe RCX. Change sounds using the sound typemodifier. This modifier must be an integer from 1to 6. Each represents a pre-programmed sound. 1:Key-click, 2: Beep Beep, 3: Descending Sweep, 4:Rising Sweep, 5: Buzz, 6: Fast Rising Sweep.

Example

This piece of code would play a fast rising sweep sound(the default).




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FlipDirectionUse this command to flip the directions of themotors once they are on. Use the ports modifierto flip specific ports. Without a modifier,

this command will flip the direction of allports. This does NOT turn the motor on. Itneeds to be used in combination with a commandthat starts the motor or at a point in yourprogram where the motor is already on.

Example

This piece of code would turn on motor A in the forwarddirection, wait one second, flip the direction of motor A(to reverse), wait one second, and then turn motor A off.

FloatOutputsUse this command if you want motors to come to amore gradual stop. This command will simply stoppowering the motors. Use the ports modifier tofloat specific ports. Without a modifier, thiscommand will float all ports.

Example

This piece of code would turn on motor A in the forwarddirection for one second then it would float the motor.




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LampUse this command to turn on lamps. The portsmodifier allows you to choose which lamps youwant to turn on. If no modifier is used, this

command will turn on all ports. Use the powerlevel command to change from 5 (bright) to 1(dim). Without a modifier, the power level willbe 5.

Example

This piece of code would turn on lamps connected to ports Aand C at power level 3. After 6 seconds, it would turn themoff.

StopOutputsUse this to stop motors or turn off lamps. Thiscommand abruptly stops motors by braking. To geta more gradual stop, use the float command. Usemodifiers to choose which ports to stop. Withouta modifier, this command stops all ports.

Example

This piece of code would turn on motors A and B in theforward direction for two seconds and then stop bothmotors.




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MotorForward MotorReverseUse this to turn on the motor(s) in the forwarddirection. Use the ports modifier to choose whichmotors to turn on. Without a modifier, this commandwill turn on all ports. Use the power level modifierto change how fast the motor spins, from 1 (slow) to 5(fast). Without a modifier, the power level will be 5(fast).

Example

This piece of code would turn on motors connected to portsA and B in the forward direction. After 4 seconds, it would

turn them off.




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MotorRandomUse this icon when you want the motor to turn onin a random direction. This icon DOES turn themotor on. The default is to turn on all ports to

power level 5.

Example

ion.

m

This piece of code turns motor A on in a random direct

otor runs for 10 seconds, and then stops.The


motChangMotorSpeed

Use this icon when you want to change or assignor speeds. This does NOT turn the motor on. It

needs to be used in combination with a commandthat starts the motor or at a point in yourprogram where the motor is already on.

eExample

This piece of code turns on motor A in the forwarddirection at full power for one second, then it changes topower level 3 for ten seconds and turns off.




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Reverse ForwardThis command just sets the direction of the motor toforward or reverse. It does NOT turn the motor on. Itneeds to be used in combination with a command thatstarts the motor or at a point in your program wherethe motor is already on. If the motor is already goingin the reverse or forward direction, there will be nochange.

Example

This piece of code assigns the speed of motor B to 3, andthe direction of motor B to reverse, and then turns it on.After 2 seconds it turns the motor off.




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RandomDirection

Use this icon when you want the direction ofthe motor to be randomly selected. This doesNOT turn the motor on. It needs to be used incombination with a command that starts the

motor or at a point in your program where themotor is already on.

Example

This piece of code turns motor A on in the forwarddirection and then randomly selects a direction for themotor (forward or backward), the motor runs for 10 secondsand is then stopped.

Use this command to turn on motors and lamps withtheir last power and direction settings.TurnOutputs

ample

On

Ex

This piece of code assigns the speed of motor B to 3, andthe direction of motor B to forward, and then turns it on.After 2 seconds it turns motor B off.




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Use this command when you want the speed anddirection of the motor related to positive andnegative numbers.

MotorForwardor BackEx ample

This piece of code puts the value -5 in the red container.It then loops 11 times running the motor at the speed inthe red container for 1 second , beeping and thenaugmenting the value of the container by 1. Hence, themotor runs backwards from speeds 5 - 1, stops while thepower is equal to 0, and the runs forward from speeds 1-5.




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MotorPower

This command will turn on motors at specifiedpower level. Indicate the motors by using theport A, B, or C icons. To specify a power level,string in a numeric constant. 1to 100 are

forward, 0 is stopped (no power), and -1 to -100are backward.

Example

Motors A and C will turn on in the forward direction atspeed 50. After 4 seconds, the motors will be turned off.




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MotorForwardOrBackString

This command will turn on motors at a power levelspecified by a string. Indicate the motors byusing the port A, B, or C icons (or encoder A, B,or C in the NXT commands menu). To specify a

power level, right-click (control-click for Macusers) on the lower right corner and chooseCreate Constant. This will allow you to type inthe name of a string variable to use to controlmotor speed.

Example

In this example, an NXT motor is trying to remain in thesame position. The value of the encoder on NXT motor A isplaced in a string container called rotation. The valuespeed is calculated using the Evaluate Expression command.Then, the variable speed is used as the power level forMotor A. This process repeats indefinitely as it is insidejump commands. Depending on the desired sensitivity anddirection the motor is connected, the values in the speed

expression may need to be modified.




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Behaviors

GoStraight

This behavior is Go Straight. This behavior is

written for a two motor car. In any behavior,you can modify the code to fit your needs.

Example

This code turns motors A and C on in the forward directionond, then turns off the motors.for 1 sec

This behavior is Turn. This behavior is written

Example

for a two motor car. In any behavior, you canmodify the code to fit your needs.Turn

is code turns motor A on forward and motor C on backward.ThAfter 0.25 seconds, the motors are turned off.




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LurchThis behavior is Lurch. It makes the car goforward then stop then go forward again anumber of times. This behavior is written for atwo motor car. In any behavior, you can modifythe code to fit your needs.

Example

one second, then off for one second. This loop repeats 10times.

In this code, motors A and C are set to go in the forwarddirection. Then a loop begins that turns the motors on for




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SnakeThis behavior is Snake. It makes the car turnfrom side to side a number of times. Thisbehavior is written for a two motor car. In anybehavior, you can modify the code to fit your

needs.

Example

This code first sets the motors for a power level of 5 (thedefault). Then it sets motor A's direction to backward andmotor C's direction to forward. It then enters a loop whichturns the motors on for one second, then reverses theirdirections. This loop repeats 10 times.




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Drive ToBump

This behavior is Drive to Bump. It makes thecar drive forward until a touch sensor ispushed. This behavior is written for a two

motor car. In any behavior, you can modify thecode to fit your needs.

Example

This code turns on motors A and C in the forward direction.When touch sensor 1 is pushed, motors A and C turn off.




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Drive ToDark

This behavior is Drive to Dark. It makes the cardrive forward until the light sensor readingdrops. This behavior is written for a two motorcar. In any behavior, you can modify the code to

fit your needs.

Example

This code turns on motors A and C in the forward direction.When the light sensor reading falls by five (the default),motors A and C turn off.




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TwoButtonRemote

This behavior is Two Button Remote. It allows youto control the direction your car drives with twotouch sensors. This behavior is written for a twomotor car. In any behavior, you can modify the

code to fit your needs.

Example

This code is written for the motors to be connected toports A and C and touch sensors to be connected to ports 1

task split is used so that each motor iscontrolled by one touch sensor in a separate task. Eachtask consists of a forever loop and a touch sensor fork.When a touch sensor is pressed, that motor turns on in the

forward direction. So, when both touch sensors are pressed,both motors go forward, causing the car to drive straight.When neither touch sensor is pressed, both motors arestopped, causing the car to stay still. If only touchsensor 1 is pressed, then only motor A is on, causing thecar to turn.

and 2. A





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StayStill

This behavior is Stay Still. It makes the carstay in the same place. If you push it, it willreturn to the original spot. This behavior iswritten for a one motor car with an angle sensor

attached to a second set of wheels. In anybehavior, you can modify the code to fit yourneeds.

Example

This program begins by resetting the angle sensor (whichsets the original spot the car will try to return to). Thena forever loop begins. In this loop, The value of therotation sensor is multiplied by 5, and this value is usedfor motor speed. In this way, the car will return to theoriginal spot (0 r

otations, moving at speed 0, or stopped)if it is pushed. If you find that your car runs away fromyou - reverse the direction of the motor of change thecontainer multiplier to a negative number. You can adjustthe sensitivity of the proportional control by adjusting

the multiplier.




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Drive AndSing

This behavior is Drive and Sing. It makes the cardrive forward while playing a song. This behavioris written for a two motor car. In any behavior,you can modify the code to fit your needs.

Example

This program uses a task split so that the car can driveand play a song at the same time. The top task turns onmotors A and C in the forward direction. After 5 seconds,it turns the motors off. The bottom task plays the redscroll. After the red scroll finishes, all outputs (thedefault) are turned off.




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SingUntilDark

This behavior is Sing until Dark. It causes theRCX to repeat a song until the light sensorreading drops below a specified value. The codeuses an event to monitor for the drop in light

sensor reading. Therefore, the reading must beginor rise above the cutoff before an event can betriggered by the drop in light sensor reading. Inany behavior, you can modify the code to fit yourneeds.

Example

This program uses an event to trigger the end of the song.A light sensor event is set up as the red event and islooking for the light sensor reading to fall below 55.Next, the program begins monitoring for the red event. Thered scroll is played in a forever loop. When the lightsensor reading falls below 55, the event will be triggered,ending the program and the song.




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SampleLight

This behavior is Sample Light. Use this tobehavior to collect light sensor data. In anybehavior, you can modify the code to fit yourneeds.

Example

This program initializes light sensor data logging, thenlogs data every 0.1 seconds. This continues until 50 datapoints have been collected, then data logging stops.

mpleAnd Dt light sensor data while

driving. This behavior is written for a two motor. In any behavior, you can modify the code to

fit your needs.

ample

This behavior is Sample and Drive. Use this tobehavior to collec

Sa rive car

Ex

This program turns on motors A and C in the forwarddirection. It then initializes light sensor data logging,and logs data every 0.1 seconds. This continues until 50data points have been collected, then data logging stops.Finally, the outputs are turned off.




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PositionControl

This behavior is Position Control. It allows formuch greater precision in car movement. Theconstant and distance can be varied. Thisbehavior is written for a one motor car. In any

behavior, you can modify the code to fit yourneeds.

Example

This program begins by optimizing RCX behavior andresetting the angle sensor. The proportionality constant,Kp, is set up as 10.5. Then a loop begins in which thevalue of the angle sensor is placed in the red container,and motor A is turned on by a power level that is computedby subtracting the red contained from 32 and multiplying bythe proportionality constant, Kp. After a 0.05 delay, theloop is repeated. The loop repeats 400 times and then motorA is turned off.




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Wait Fors

Wait for1 second Wait for2secondsWait for4seconds

Wait for6secondsWait for8seconds

Wait for10secondsUse these icons if you want to wait for the specifiedamount of time before moving on to the next command.Useful to choose duration of motor and lamp activity.

Example

This piece of code would turn on motor A in the reversedirection for 2 seconds, and then turn it off.


Wait forTimeto choose duration of motor and

lamp activity.

ample

Use this icon if you want to specify the numberof seconds to wait before moving on to the nextcommand. Useful

Ex

itThis piece of code would turn on motor A for the number ofseconoff.

ds specified on the control panel and then turn




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Wait forRandomTime

this if you want to wait a random amount oftime before moving on to the next command. Usemodifier to change the max random time from 5

seconds. Useful to choose duration of motor and

e

Use

lamp activity.

Exampl

of code would turn on motor A for a randomieceamount of time between 0 and 5 seconds and then turn itThis p

off.

Wait fornthousandthsof asecon

Use this if you want to wait a certain numberof thousandths of seconds before moving on tothe next command. Useful to choose durationof motor and lamp activity.

dExample

ece of code would turn on Motor A and C for a thef thousandths of seconds specified on the control

sor was pressed, in which case both motors wouldrn off.

This pinumber opanel, then run Motor A forward and B backward until a

touch sentu




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it for Nhundredthsof a second

dths of seconds before moving on tothe next command. Useful to choose durationof motor and lamp activity.

Example

Use this if you want to wait a certain numberof hundre

Wa

This piece of code would turn on motor A for the number ofhundredths of seconds specified on the control panel and

then turn it off.




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Wait forTime(min)

Use this if you want to wait a certain number ofminutes before moving on to the next command.Useful to choose duration of motor and lampactivity.

Example

This piece of code would turn on motor A for the number of

minutes specified on the control panel and then turn itff.o

Wait for 100Points Wait for 500PointsWaitintfor 10so

ul in Investigator. Use these icons when youollect the specified number of data points

Most usefant to cw

before moving on to the next command.

Example

This piece of code clears the data memory, then logs 500points of rotation sensor data.




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Wait forN Points

Most useful in Investigator. Use this icon whenyou want to collect a certain number of datapoints before moving on to the next command.

Example

mailb

This piece of code would take 50 data points from theox.

WaitPush

Use this icon to wait for something to push inthe touch sensor before moving on to the next

mand.

ample

for com

Ex

If an IP number was strung onto the Begin icon, this pieceof code would be sent over the Internet. It would turn onmotor A until a touch sensor was pressed and then shut itoff.




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Wait forLet Go

Use this icon to wait for something to releasethe touch sensor before moving on to the nextcommand. If the touch sensor is not pressed tobegin with, the touch sensor must be pressed then

released.

Example

If an IP number was strung onto the Begin direct icon, thispiece of code would control an RCX in direct mode over theInternet. It would turn on motor A on the remote RCX untila touch sensor was released and then turn it off.


Wait forghtain value before moving

on to the next command.

ample

Use this icon to wait for the light reading tobecome greater than a cert

LiEx

This piece of code turns on motor A, then waits for thelight sensor to read a value greater than 55 (the default).Then, it turns off the motor.




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Wait forDark

Use this icon to wait for the light reading tobecome less than a certain value before moving onto the next command.

Example

This piece of code turns on motor A, then waits for thelight sensor to read a value less than 55 (the default).Then, it turns off the motor.


Wait forBrighertain value before moving to the

next command.

ample

Use this icon to wait for the light reading toincrease by a c

terEx

This piece of code turns on motor A, then waits for thelight reading to increase by 5 (the default). Then, itturns off the motor.




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Wait forDarker

Use this icon to wait for the light reading todecrease by a certain value before moving to thenext command.

Example

This piece of code turns on motor A, then waits for thelight reading to decrease by 5 (the default). Then, itturns off the motor.

Wait forRotationw/o Reset

e

teenths, so a reading of 16is one rotation.

Use this icon to wait for a number ofrotations (or a fraction of a rotation) to bcompleted but do NOT want to reset therotation sensor to 0. (The general wait forrotation sensor resets to 0 and then waits forthe cutoff rotation.) The angle sensor valueis measured in six

Example

This piece of code turns on lamp A, waits for 1 rotation (areading of 16, the default) from the sensor, then turnslamp A off.




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Wait forAngle

Use this icon to wait for the angle sensor valueto be greater than the cutoff value before movingon to the next command. The rotation can beeither forward or backward. The default is 180

degrees, or half a rotation.

Example

This piece of code turns on lamp A. Once the angle sensorreads a value of greater than 180 degrees (the default),lamp A turns off.


Wait forRotation sixteenths, so a reading of

ample

Use this icon to wait for the angle sensor valueto be greater than the value specified beforemoving on to the next command. The angle sensorvalue is measured in16 is one rotation.

Ex

This piece of code turns on lamp A. Once the angle sensorvalue reaches 16 (or one rotation, the default), lamp Aturns off.




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NXTWaitforPush

Use this icon to wait for something to push inthe touch sensor before moving on to the nextcommand.

Example

This piece of code waits until the NXT touch sensor on Port

for 2

1 is pressed, in which case Motors A and C go forward untilthe touch sensor is pressed again. When it is pressed,Motor A will continue forward and Motor C will go backward

seconds, then both motors will stop.


the new NXT touch sensor before moving on to thenexXTWaitForLet

Go

Use this icon to wait for something to release

t command. If the touch sensor is not pressedto begin with, the touch sensor must be pressedthen released.

Example




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released, Motor A will continue forward and Motor Cwill go backward for 2 seconds, then both motors will stop.

This piece of code waits until the NXT touch sensor on Port1 is pressed. While it is pressed, Motors A and C goforward until the touch sensor is released. When it is

Use this icon to wait for the light reading tobecome greater than a certain value beforeoving on to the next comm

XTaitLight

and.

Example

Wform

This piece of code turns on Motor A, then waits for thelight sensor on Port 1 to read a value greater than 36.Then, it turns off the motor.




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NXTWaitforDark

Use this icon to wait for the light reading tobecome less than a

certain value before moving on to the nextcommand.

Example

This piece of code turns on motor A, then waits for thelight sensor to read a value less than 30. Then, it turnsoff the motor.


NXTWaitforBrighter

increase by a certain value before moving to the

ample

Use this icon to wait for the light reading to

next command.

Ex

This piece of code turns on motor A, then waits for thelight reading to increase by 10. Then, it turns off the




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.motor

NXT WaitforDarke

Use this icon to wait for the light reading todecrease by a certain value before moving to thenext command.

rExample

This piece of code turns on motor A, then waits for thelight reading to decrease by 10. Then, it turns off themotor.




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NXTForwardDistanceX

Use this icon to wait for the distance sensor to

read a distance (in cm) that is greater than thenumber specified before moving onto the nextcommand.

Example

ece of code turns on Motor A, then waiThis pidistance

ts for thesensor to have a value of greater than 10, in

which case it stops. It then waits for the distance sensorto read a value less than 10. Next, it jumps back to thebeginning of the program and starts again.




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NXTReverseDistanceX

Use this icon to wait for the distance sensor toread a distance (in cm) that is less than the

number specified before moving onto the nextcommand.

Example

ece of code turns on Motor A, then waiThis pidistance

ts for thesensor to have a value of greater than 10, in

which case it stops. It then waits for the distance sensorto read a value less than 10. Next, it jumps back to thebeginn

ing of the program and starts again.

TWaitforLoud

Use this icon to wait for the sound sensor tonotice a volume greater than the specified cutoffbefore moving onto the next command.NX

Example

This piece of code turns on Motors A and C, then waits for




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the sound sensor to notice a volume greater than 70, inwhich case Motors A and C reverse. It then waits for thesound sensor to read a value less than 35. Next, itjumps back to the beginning of the program and startsain.

ag

NXTWaitforQuiet

Use this icon to wait for the sound sensor tonotice a volume less than the specified cutoffbefore moving onto the next command.

Example

This piece of code turns on Motors A and C, then waits forthe sound sensor to notice a volume greater than 70, inwhich case Motors A and C reverse. It then waits for the

sound sensor to read a value less than 35. Next, it jumpsback to the beginning of the program and starts again.




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NXTLouderUse this icon to wait for the volume to increase

by the cutoff value before moving onto the nextcommand.

Example

This piece of code turns on Motors A and C, then waits fothe volume to in

rcrease by 15, in which case Motors A and C

It then waits for the volume to decrease by 20.Next, it jumps back to the beginning of the program andstarts again.

reverse.

NXTQuieter

icon to wait for the volume to decreaseby the cutoff value, before moving onto the next

command.

ample

Use this

Ex

This piece of code turns on Motors A and C, then waits forthe volume to increase by 15, in which case Motors A and Creverse. It then waits for the volume to decrease by 20.Next, it jumps back to the beginning of the program andtartss again.




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be completed but do NOT want to reset therotation sensor to 0. (The general wXT

rRotationw/oReset

Use this icon to wait for a number of degrees to

ait fortation sensor resets to 0 and then waits for

the cutoff degree.)

Example

Wait rofo

This piece of code turns on Lamp A, waits for 720 degreesfrom the sensor, then turns Lamp A off.




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Wait forDecreasingTemp (C)Wait forIncreasingTemp (C)

Wait forDecreasingTemp (F)Wait forIncreasingTemp (F)

Use these icons to wait for the temperature sensor toread a value less (Wait for Increase) or greater than(Wait for Decrease) than the cutoff temperaturespecified before moving on to the next command.

Example

This piece of code turns on lamp A,then waits for thetemperature sensor to read above 30 degrees Celsius (thedefault). After that it plays a sound and turns off thelamp.




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Use this icon to wait for the value of acontainer to be equal to some number beforemoving on to the next command.Wait for

Conta ampleinerEx

This piece of code empties the red (default) container.

Then it turns on motor A. It waits for the container valueto equal 1 (the default), and when it does, it turns offmotor A and stops all tasks. At the same time, a secondtask is filling the container with the value of the touchsensor. In essence, this program waits for the

touch sensorto be pressed, and then turns off the motor.


Wait forMail

for mail before moving onto the next command.

Example

Use this icon to wait

mail. Once the mail is received, it turns off motor A.This piece of code turns on motor A and waits to receive




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Wait forClock

Use this icon to wait for the clock on the RCX toreach a certain time value in minutes beforemoving on to the next command. Useful if you do

not want the RCX to stay on too long to conservebatteries.

Example

This piece of code turns on lamp A and waits for the RCXclock to reach 1 minute (the default), then turns off thelamp.




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Use this icon to wait until the clock reaches acertain time (measured in tenths of seconds)before moving on to the next command. Always usea zero timer command prior to this command.

Wait forTimerExample

This program zeros the red timer and turns on motor A. Thenit waits for the red timer to reach 1 second (the default),after which it stops motor A.

WaitforTimer

Use this icon to wait until the timer (read inhundredths of seconds) reaches a certain timebefore moving on to the next command. Always usea zero timer command prior to this command.

Example

This program zeros the red timer then it waits for the redtimer to reach 600 hundredths of seconds, after which itbeeps.




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Wait for Increasein Camera Sensor

Wait for Decreasein Camera Sensor

Use these icons to wait until the camera sensor readsa value higher (Increase icon) or lower (Decreaseicon) than the compare to number before moving on tothe next command.

Example

This piece of code would turn on motor A. When the camerasensor reads a value of greater than 55 (the default), Themotor would turn off and the RCX would play a sound.




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Wait for Decreasein Voltage(Generic)

Wait for Incin Voltage rease(Generic)

Use these icons to wait until the sensor reads avoltage of less than (Wait for Decrease icon) orgreater than (Wait for Increase icon) the cutoffvoltage specified before moving on to the nextcommand.

Example

This piece of code would turn on motor A. When the sensorreads a value of less than 2 Volts (the default), motor Awould turn off.

Wait forDecreasingHumidityWait forIncreasingHumidity

Use these icons to wait until the sensor reads a valueof less than (Wait for Decrease icon) or a value ofgreater than (Wait for Increase icon) the cutoffhumidity percentage before moving on to the nextcommand.

Example

This piece of code would turn on motor A. When the sensoreads a value of less than 5

r0% humidity (the default),

motor A would be shut off.




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Wait forDecreasing pH Wait for DecreasingpH

the cutoff pH before moving on to the

ample

Use these icons to wait until the sensor reads a valueof less than (Wait for Decrease) or greater than (Waifor Increase) tnext command.

Ex

r

ater than 7 (the default), motor Awould be shut off.

This piece of code would turn on motor A. When the sensoreads a value of gre

Wait for PositionIncrease Wait for PositionDecreaselue

cutoff position before moving on to the next command.

ample

Use these icons to wait until the sensor reads a va

of less than (Wait for Position Increase icon) orgreater than (Wait for Position Decrease icon) the

Ex

This piece of code would turn on motor A. When the sensorreads a value of less than 180 degrees (the default), the

motor would be shut off.




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Wait forIncreasingPressure

Wait forDecreasingPressure

Use these icons to wait until the sensor reads a valueof less than the cutoff pressure before moving on tothe next command.

Example

This piece of code would turn on motor A. When the sensorreads a value of less than 100 kPa (the default), the motorwould be shut off.

Wait forIncreasing SoundLevelWait forDecreasing SoundLevel

Use these icons to wait until the sensor reads a valueof less than (Wait for Increase icon) or greater than(Wait for Decrease icon) the cutoff sound level beforemoving on to the next command.

Example

This piece of code would turn on motor A. When the sensor

reads a value of less than 60 decibels (the default), themotor would be shut off.




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Wait forIncreasingTemperature (C)Wait for Decrease

icon) or greater than

to the next command.

Example

in Temperature (C)

Use these icons to wait until the sensor reads a valueof less than (Wait for Increase(Wait for Decrease icon) the cutoff temperature beforemoving on

This piece of code would turn on motor A. When the sensorreads a value of less than 30 degrees Celsius (thedefault), the motor would be shut off.

Wait for Increasein Voltage Wait for Decreasein VoltageUse these icons to wait until the sensor reads a valof less than (Wait for Increase

ueicon) or greater than

to the next command.(Wait for Decrease icon) the cutoff voltage beforemoving on

Example

This piece of code would turn on motor A. When the sensorreads a value of less than 2V (the default), the motorwould be shut off.




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Tasks & Subroutines(Structures)Use this icon to start a new task. The tasks runsimultaneously. Each task needs an End icon(stoplight).TaskSplit ampleEx

This piece of code turns on motor A. After 2 seconds itflips directions, and after 4 seconds from the beginning (2seconds from flip) it turns off motor A.

artTaskis

o restart a

Example

Use this to restart tasks after they have beencompleted or stopped. The Task Number modifier

only necessary if you only wish tSt certain task and not all tasks.

This piece of code turns on motor A and lamp B. If 6seconds pass and the touch sensor has not been pressed, theRCX will play a noise and turn off lamp B. Then both taskswill be restarted from the task split. If the touch sensoris pressed within 6 seconds, both tasks will be stopped and




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the program ends.

Delete eber modifier is only necessary if youwant to delete only a certain task and not all

ks.

Example

Use this in direct mode ONLY. Use this icon to

clear the RCX of any tasks it previously had. ThTask NumTaskstas

This piece of code deletes all tasks then turns on motor A

for 2 seconds and turns it off.

opTaskssk Number modifier is only

necessary if you want to stop a certain task andall ta

Example

Use this to stop tasks that may still be inprogress. The Ta

St not sks.

This piece of code turns on motor A and lamp B. If 6seconds pass and the touch sensor has not been pressed, theRCX will play a noise and turn off lamp B. Then both taskswill be restarted from the task split. If the touch sensoris pressed within 6 seconds, both tasks will be stopped andthe program ends.




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CreateSubroutine

Use this to define a subroutine. This does NOTstart the subroutine. Each subroutine needsits own end (stoplight) icon. The main taskwill continue running by itself until a Run

Subcommand is reached.

Example

This piece of code turns on motor A. After 4 seconds it

plays 3 notes and then turns off the motor.

Use this to start a subroutine. You mustdefine the subroutine before using thiscommand.

StartSubroutineExample

This piece of code turns on motor A. After 4 seconds itplays 3 notes and then turns off the motor.




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Use this in direct mode ONLY. Use this icon toclear the RCX of any subroutines it previouslyhad.

DeleteSubroutineExample

This piece of code clears the RCX of any subroutines andthen turns on motor A for 2 seconds and turns it off.




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Forks

TouchSensorFork

Use this fork if you want to take differentcourses of action based on a touch sensor. A forkmerge is required at some point after this icon.

Example

This piece of code would turn on motor A. If, after 4seconds, the touch sensor is pushed, the RCX will play asound and shut off the motor. Otherwise, the motor willjust be turned off (no sound).




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NXTSoundSensorFork

Use this fork if you want to take differentcourses of action based on volume, as read by the

NXT sound sensor fork. A fork merge is requiredat some point after this icon.

Example

This piece of code checks the volume of a room as read by the sound sensor. If the volume is greater than 40, a sound is playit is less than 40, Motor A runs in reverse for two seconds. Ijumps back to the beginning of the code to start again.




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NXTDistanceSensorFork

Use this fork if you want to take differentcourses of action based on distance from thesensor (in cm), as read by the NXT distance

sensor fork. A fork merge is required at somepoint after this icon.

Example

This piece of code runs Motor A in reverse if the distancesensor reads a value of less than 10. It continues goingbackward (because of the red jump and land) until thedistance sensor reads a value greater than 10, in whichcase it will run Motor A forward until a distance of 10 isreached again. This process continues over-and-over.




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NXTRotationSensorFork

Use this fork if you want to take differentcourses of action based on the NXT rotationsensor. A fork merge is required at some point

after this icon.

Example

This program waits 1 second, then if the rotation sensor onPort A reads less than 720 degrees, Motor A goes forward.This continues (because of the red jump and land) until the

rotation sensor reads above 720 degrees, in which case itwill stop Motor A, play a sound, and reset the angle sensorto zero.




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NXT LightSensorFork

Use this fork if you want to take differentcourses of action based on a light sensor. A forkmerge is required at some point after this icon.

Example

This piece of code turns on Motor A for 4 seconds if theNXT light sensor (on Port 2) reads a value of below 55. Ifthe value is greater than 55, a sound is played.




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NXT ClickFork

Use this fork if you want to take differentcourses of action based on the number of clickson a touch sensor. A fork merge is required atsome point after this icon. Also, a zero clicks

sensor command should be used sometime beforethis icon.

Example

This piece of code first resets the click counter to zero.It then turns on Motor A for 10 seconds, and will shut itoff for two seconds if the click counter has a value ofless than 5. If it is greater than five, it plays a sound.It then jumps back to the beginning and starts again.




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Use this fork if you want to take differentcourses of action based on the value of a timer.A fork merge is required atTFoimerrk

some point after thisicon.

Example

This piece of code turns on lamp A for a random amount oftime, and then turns it off. If the time is less than 3seconds, the RCX plays a sound.




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ClickFork

Use this fork if you want to take differentcourses of action based on the number of clickson a touch sensor. A fork merge is required atsome point after this icon. Also, a zero clicks

sensor command should be used sometime beforethis icon.

Example

This piece of code turns on motor A for 10 seconds, then

shuts it off. If after 10 seconds the touch sensor has beenlickc ed more than 10 times, it plays a sound.


TouchandReleaFork

mber of touchesand releases on a touch sensor. A fork merge is

uired at some point after this icon. Also, azero touch and release sensor command should beused sometime before this icon.

Use this fork if you want to take differentcourses of action based on the nu

se req

Example

This piece of code turns on motor A for 10 seconds, andthen shuts it off. If after 10 seconds the touch sensor hasbeen touched and releases more than 10 times, it plays asound.




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DataPointsFork

Use with Investigator commands. Use this fork ifyou want to take different courses of actionbased on the number of points gathered. A forkmerge is required at some point after this icon.

Example

This piece of code logs light sensor data points for a

random time. If after that time there are 5 (the default)or fewer data points, it logs data for 2 more secondsbefore stopping. If after the random time there are greaterhant 5 data points, it stops logging points.


lockFork

Use this fork if you want to take differentrses of action based on the value of the RCX

clock. A fork merge is required at some pointafter this icon.

cou

Example

This piece of code would check the value of the RCX clock.If the clock read 1 minute (the default) or less, thenmotor A would turn on for 8 seconds.




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HumiditySensor Fork pH SensorFork PressureSensorFork

Sound LevelSensor Fork

TemperatureSensor Fork PositionSensorForkVoltage Fork

fk

merge is required at some point after this icon.

ample

Use this fork if you want to take different courses oaction based on the value of a LogIT sensor. A for

Ex

This piece of code would play a sound if the value of thehumidity sensor was less than or equal to 50% (thedefault).




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CelsiusEqualFork

Use this fork if you want to take differentcourses of action based on a temperature sensor.A fork merge is required at some point after thisicon.

Example

This pi

e

ece of code waits one second and reads the

fault), it will play a sound.temperature. If the temperature is not 30 degrees Celsius(the d

cocontainer. A fork merge is required at someContainerEqual Fork

Use this fork if you want to take differenturses of action based on the value of a

point after this icon.

Example

This piece of code fills a container with a random number.If that number is not equal to 1 (the default), the RCXplays a sound.




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FahrenheitEqual Fork

Use this fork if you want to take differentcourses of action based on a temperaturesensor. A fork merge is required at somepoint after this icon.

Example

This piece of code waits one second and reads thetemperature. If the temperature is not 80 degrees

ahreF nheit (the default), it will play a sound.


ilbEqualForkcourses of action based on the value of the

lbox. A fork merge is required at some pointafter this icon. Also, an empty mailbox commandshould be used sometime before this icon.

Use this fork if you want to take different

Ma oxmai

Example

of 1 (the default), the RCX plays a sound.

This piece of code empties the mailbox and then waits 10seconds. If after those 10 seconds the mailbox has a value




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RotationSensorEqualFork

Use this fork if you want to take differentcourses of action based on a rotation sensor. Afork merge is required at some point after thisicon. Also, a zero angle sensor command should be

used sometime before this icon. Reminder:rotation sensor reads in sixteenths, so a readingof 16 equals one rotation. Rotation can be eitherforward or backward.

Example

This piece of code zeros the angle sensor. If after 10seconds the angle sensor reads 16 (one rotation, thedefau

lt), then the RCX plays a sound.


ClickualForkensor. A fork merge is required at

some point after this icon. Also, a zero clickssor command should be used sometime before

this icon.

ample

Use this fork if you want to take differentcourses of action based on the number of clickson a touch s

Eqsen

Ex

This piece of code zeros the click sensor. If after 10seconds the click sensor reads 10 (the default), the RCXplays a sound.




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TouchandReleaseEqualFork

Use this fork if you want to take differentcourses of action based on the number of touchesand releases on a touch sensor. A fork merge is

required at some point after this icon. Also, azero touch and release sensor command should beused sometime before this icon.

Example

This piece of code zeros the touch and release sensor. Ifafter 10 seconds the touch and release sensor reads 10 (thedefault), the RCX plays a sound.

NXTSound


SensorEqualFork

courses of action based on the volume of a room,as measured by the NXT sound sensor. A fork mergeis required at some point after this icon.

ample

Use this fork if you want to take different

Ex

iece of code turns on motor A. If the sound sensorot read a value of 55, then the RCX plays a s

This ps n ound.er 2 seconds, the motor is shut off.

doeAft




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DistanceSensoEqualFork

Use this fork if you want to take differentcourses of action based on the volume of a room,as measured by the NXT sound sensor. A fork merge

Example

NXTr is required at some point after this icon.

This piece of code turns on Motor A in reverse if thevolume is not equal to 10. If the volume is equal to 10, asound is played. The code then jumps back to the beginningto start again.




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NXTLightSensorEqualFork

Use this fork if you want to take differentcourses of action based on a light sensor. Afork merge is required at some point afterthis icon.

This piece of code turns on motor A. If the light sensordoes not read a value of 55, then the RCX plays a sound.After 2 seconds, the motor is shut off.




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NXTClickEqualFork

Use this fork if you want to take differentcourses of action based on the number of clickson a touch sensor. A fork merge is required atsome point after this icon.

Example

This piece of code will turn Motor A on at Power Level 10for 1 second if the value of the click count sensor is notequal to 10. If it is equal to 10, Motor A will stop for 1second, a sound will played, and the click sensor will bereset to zero. This code then jumps back to the beginningto begin again.




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DataPointsEqualFork

Use with Investigator commands. Use this fork ifyou want to take different courses of actionbased on the number of points gathered. A forkmerge is required at some point after this icon.

Example

This piece of code logs light sensor data points for 6seconds. If after that time there are not 5 (the default)data points, the RCX plays a sound before stopping. Ifafter the 6 seconds there are 5 data points, it stopslogging points (no sound).




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ClockEqualFork

Use this fork if you want to take differentcourses of action based on the value of the RCXclock. A fork merge is required at some pointafter this icon.

Example

This piece of code would check the value of the RCX clock.If the clock did not read 1 minute (the default), thenmotor

A would turn on for 8 seconds.


Cameranso rqualFork

camera sensor. A fork merge is required at somepoint after this icon.

ample

Use this fork if you want to take differentcourses of action based on the value of the

SeE

Ex

then turn it off. The direction of the motor is determinedby the value of the camera sensor. If the camera value is55 (the default), the motor goes forward. Otherwise, themotor goes in the reverse direction.

Documents

Rl-ReferenceGuide