Coding for the FIRST Tech Challenge:

RobotC

Presented by:Audrey Yeoh

Acknowledgements: Team Unlimited FTC 0001

Why RobotC?

SpeedRobotC runs quicker on the NXTDifferences in speed are small until larger code is written

Control In RobotC you have control over almost everythingReal Time Debugger to allow viewing of code line by line while

running Personal Preference

Text base controlAdvanced math functionsTeam Decision

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Hardware Review

ServoCan only go 180 degrees In code, it is from 0 to 255

DC MotorContinuousControlled by power rather than degree (+100

forward to -100 backward)

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0 255

180°

Plan the Code

Get a diagram of the field Draw the general routine w/ arrows and numbers Make side notes noting what happens at each time interval Start your first draft of the code

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Coding Basics

Comments:“//” is used as a line comment“/*” is the beginning of a group comment“*/” ends a group commentComments never affect the function of codeAlways comment code so your team members

understand it!

Example:

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Dead Reckoning vs. Sensing

Dead ReckoningA prewritten routineCode flows A to B to C If interrupted, will only try to continueEasier to write

Sensing Routine that can adaptCode flows, but can respond If interrupted, can attempt to correctMore complicated

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Reacting to the Environment

Sense the world and react to itTouch switch is pressed, against somethingUltrasonic rapidly changes, something crossed pathsLight sensor spikes, on a line or off a line

Useful to be able to change course Code “thinks” for itself Only as smart as YOU code it!

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Flow of the Code

Flow from place to placeDON’T JUMP ALL OVER THE PLACE!Structure the code ahead of time, plan it out

Make things easy to fixMake your code neat and clean

Plan the code out ahead of timeDon’t haphazardly place code in

Order your codeDo you want an interrupt? Is there an importance to the steps?

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Commenting

Use comments to remind yourselfOften you will forget why something is in the codeExplains to the JUDGES what you were thinkingAllows for easy correctionsWrite complete thoughts

“Checks for a touch sensor being pressed, if not, continue”Use them LIBERALLY

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RobotC Home Screen

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RobotC Basics

Make sure you are on version 3.00 If not, uninstall RobotC COMPLETELY before installing the newest

version Use the Sample codes included in RobotC

Access by File > Open Sample Programs Save RobotC files in separate location on Hard Drive Download and watch coding presentations at Robotics

Academy

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Connect NXT

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Select NXT Brick

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Selecting the Firmware

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Download and Complete

Make sure this message appears before exiting

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Rename NXT

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Name Your NXT

Type in the name for your NXT (default is NXT) Recommended name is your team number to four

digits (i.e FTC #0001 is 0001 If you have more than one NXT, place an A, B, etc. after

the number

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Connecting to Bluetooth

1. Go to Robot > NXT Brick > Link Setup

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Connecting to Bluetooth

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2. Make sure that this box is checked to perform a bluetooth search

2. Select here to make a pair between the NXT and your laptop

Bluetooth at the Competition

Take from the Field Preparation Guide (you can find it here)

Remember to always do these steps at the Playing Field

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Bluetooth at the Competition

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RobotC Menu

Compile and DownloadCompiles and downloads

Compile ProgramCompiles locally

DebuggerScans code for errors

Motor & Sensor SetupSet up Motor and Sensors

Download firmwareDownload firmware to NXT

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RobotC Menu

Link SetupUsed to establish a link

between NXT and Computer

Poll Brick “Online Window”

File ManagementManage files on the NXT

Joystick Control“FTC Controller Station”

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RobotC Debugger

Allows for program control wirelessly

Allows to view where the code is currently

Allows to view errors in your code while running

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RobotC Debugger Buttons

Start/Stop – Starts or Aborts Program Suspend – Pauses code Step Into – Pauses code and proceeds to next line Step Over – Pauses code and skips over next

procedure Step Out - Pauses code and exits procedure Clear All – Resets all values to default Refresh Rate

Once – Refreshes values manually Continuous/Stop – Switch between continuous

and stop updating

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RobotC Debugger Joystick Control

“FTC Controller Station”

Allows control over Teleoperator and Autonomous

Views controller data

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RobotC “Loops”

While statementPerforms code as long as the statement is true

I.e. while (ServoValue[Servo1] < 255) If statement

Performs entirety of code if statement is trueI.e. if (sensorValue[Touch] == 0)

Else statementPerforms entirety of code if “If Statement” is false

i.e. else

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RobotC Punctuation

Brackets { }Used to control flow of code

Semicolons ;Used after lines to denote an end

Square Brackets [ ]Used for sensors and motor declarations

Parenthesis ()Used for time and math functions

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RobotC Operators

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== (test a condition)i.e. while (sensorValue[Touch] == 0)

= (equals)i.e. motor[motorD] = 0;

< , > (less than, greater than)i.e. if ( -10 < joystick.joy1_y1 < 10 )

|| (or)i.e. if ( joy1Btn(1) || joystick.joy2_TopHat == 0 )

RobotC Commenting

// TEXTComments out a single line of text

/* TEXT */Comments out all text within the /* and */

/*Comments out all text after

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RobotC Simple Program

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Sample Code

FTC Template Joystick Control DC Drive Motor sample NXT Motor sample Servo sample Touch Sensor sample Light Sensor sample Ultrasonic Sensor sample Compass Sensor sample

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Teleop Template

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Autonomous Template

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Joystick Control Sample

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DC Motor Sample

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NXT Motor Sample

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Servo Sample

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Touch Center Sample

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Light Sensor Sample

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Light Sensor Sample

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Ultrasonic Sensor Sample

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Compass Sensor Sample

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Field Diagram

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RobotC Resources

RobotC RobotC Forums Robotics Academy FTC Function Guide (From Robotics Academy) Setting up Dual Template Mode Field Procedures for Bluetooth Software Information (Links at our website) Code and Software Presentation

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RobotC Resources

RobotC Sample codeProgram files > Robotics Academy > RobotC for Mindstorms >

Sample Programs > NXTFile > Open Sample Programs (if RobotC is open)

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Coding for the FIRST Tech Challenge:

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Questions?

Programming Structures

Clean codeReadable to humansComment and MethodsReiteration

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Variables

What are variables?They are things you store in the program that

you may want to useHow are they made?They are made according to their ‘types’ eg.

Integer (int)Example Structure:

int apple = 0; If they occur outside { } of any methods, they

are instance variables

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Variables Continued…

Variables are ‘alive’ only in the highest method they are in

‘Dead’ Variables can be used againEg.

Void appleCount {int apple = 3;

}

Void pearCount{int apple = 4

}

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Variables continued…

So why have different variable names?To avoid confusion!

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Camel Casing

thisIsCamelCasingCapitalizing the first letter of a word in a

sentence starting from the second wordLooks like camel humpsWhy? Not to confuse with other commandsCamel Casing is used for variables you make

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For Loop

Does the loop for a specific number of timesKnown repeat numberStructure:

for(int i=0; i< (number of times you want to repeat it; i++){

//code

}

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While Loop

Want to repeat itUnknown number of times of repeatExample Structure:

while ( sensorVal < 100){

// code

}

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If … Else… Statements

If something is true, do this, or else do something else

Example Structure:

if ( sensorVal == 4){//code for dance happy dance

} else{//code for go forward

}

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Methods

What are methods?Methods are things that you can call to do over

and over again (eg. Move forward 5 cm)Why use methods? Reiteration Robot Code example (activity)Example Structure:

void danceRobotDance{// make robot dance

}

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