NXT 2.0 Instructions

12/30/12 NXT 2.0 Instructions

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LEGO Mindstorms NXT 2.0 instructions

Instructions for building the Shooterbot, Robogator, Color Sorter, and Alpha Rex.

Table of contents

IntroductionProgramming the NXT with LinuxCompiling an NXC program

Shooterbot1. Driving base2. Color detection3. Shooter4. Locate objects

Robogator1. Jaws2. Eyes3. Legs4. Tail

Color Sorter1. Dispenser2. Color detector3. Sorting tray4. Color catapult

Alpha Rex1. Legs2. Arms3. Head4. Color sensor

Introduction

The instructions for building the four main LEGO Mindstorms NXT 2.0 models are distributed only on software that doesnot support Linux. The instructions are reproduced here.

Programming the NXT with Linux

The accompanying programs supplied here are written in NXC. NXC is a simple C-like programming languagesupported by NBC. NBC allows you to write NXT programs and download them to the NXT. This configuration guide forNBC on Linux is useful.

Compiling an NXC program

A typical command to compile and download an NXC program by USB would be

nbc -d -S=usb filename.nxc

Shooterbot

Can you build and program a Shooterbot to guard your room while you are away?

1. Driving base

Building guide

http://arbitrarycreations.co.uk/bash/

http://arbitrarycreations.co.uk/c/

http://arbitrarycreations.co.uk/celestial/

http://arbitrarycreations.co.uk/lego/

http://arbitrarycreations.co.uk/various/

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_drivingbase_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_drivingbase_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_drivingbase_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_colordetection_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_colordetection_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_colordetection_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_shooter_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_shooter_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_shooter_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_locateobjects_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_locateobjects_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot_locateobjects_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_jaws_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_jaws_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_jaws_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_eyes_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_eyes_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_eyes_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_legs_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_legs_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_legs_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_tail_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_tail_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator_tail_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_dispenser_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_dispenser_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_dispenser_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_colordetector_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_colordetector_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_colordetector_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_sortingtray_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_sortingtray_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_sortingtray_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_colorcatapult_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_colorcatapult_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#colorsorter_colorcatapult_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_legs_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_legs_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_legs_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_arms_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_arms_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_arms_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_head_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_head_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_head_test

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_colorsensor_build

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_colorsensor_program

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpharex_colorsensor_test

http://arbitrarycreations.co.uk/contact/

http://arbitrarycreations.co.uk/

http://arbitrarycreations.co.uk/search/

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#intro

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#nbc

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#nbc_compile

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#shooterbot

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#robogator

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#color_sorter

http://arbitrarycreations.co.uk/lego/nxt_2_instructions/#alpha_rex

http://en.wikipedia.org/wiki/Lego_Mindstorms_NXT#NXT-G

http://bricxcc.sourceforge.net/nbc/

http://www.eggwall.com/2011/07/setting-up-lego-programming-environment.html



Can you build a Shooterbot to move forward and then move back again?





















Programming guide

Can you program a Shooterbot to move forward on the test pad and then move in reverse to its start position?

// shooterbot_1.nxc// Move forward and then reverse.

task main (){ // Move forward at 75% power for 2 seconds OnFwd (OUT_BC ,75); Wait (2000);

// Reverse at 75% power for 2 seconds OnRev (OUT_BC ,75); Wait (2000);

// Brake Off (OUT_BC);

}



}

Test guide

Download your program. Place the Shooterbot on the test pad and run the program.

2. Color detection

Building guide

Can you build a Shooterbot to test colors on the test pad?



Programming guide

Can you program a Shooterbot to move forward, find the red line, turn around, and then move back to its start

position?

// shooterbot_2.nxc// Move forward to the red line, turn around, and move back to the start// position.

// Adjust this number to suit your surface / battery power#define TURN_TIME 1750

task main (){ long t0, t1;

// Bring the color sensor on-line



// Bring the color sensor on-line SetSensorColorFull (S3);

// Record the time when the forward movement starts t0 = CurrentTick ();

// Move forward to the red line OnFwd (OUT_BC ,75); until (INPUT_REDCOLOR == SENSOR_3); t1 = CurrentTick (); // Record the time when the forward movement finishes Off (OUT_BC);

// Turn 180 degrees to the right OnFwd (OUT_C, 75); OnRev (OUT_B, 75); Wait (TURN_TIME); Off (OUT_BC);

// Move back to the start OnFwd (OUT_BC ,75); Wait (t1 - t0); Off (OUT_BC);}

Test guide

Download your program. Place the Shooterbot on the test pad and run the program.

3. Shooter

Building guide

Can you build the Shooterbot to shoot balls at objects? You will have to build the shooter on the front of your

Shooterbot.













Programming guide

Can you program Shooterbot to drive around and shoot while showing different colored lights?

// shooterbot_3.nxc// Drive around and shoot while showing different colored lights.

#define BULLETS 7#define FLASH_DURATION 300#define TURN_TIME 3000

int bullets_remaining = BULLETS;bool fire = false;

task flashing_lights (){ int red_flashes;

while (bullets_remaining > 0) { // Alternate between the red, green, and blue lamps SetSensorColorRed (IN_3); Wait (FLASH_DURATION); SetSensorColorGreen (IN_3); Wait (FLASH_DURATION); SetSensorColorBlue (IN_3); Wait (FLASH_DURATION); }

// Indicate that no bullets remain for (red_flashes = 1; red_flashes <= 10; red_flashes++) { SetSensorColorRed (IN_3); Wait (FLASH_DURATION / 2); SetSensorColorNone (IN_3); Wait (FLASH_DURATION / 2); }

// Stop the program StopAllTasks ();}

task shoot (){ while (true) { // Check whether to fire a bullet if (true == fire) { // Reset the 'fire a bullet' flag to false fire = false;



// Decrement the number of bullets remaining bullets_remaining--;

// To fire, make motor A do a single 360 degree rotation RotateMotorEx (OUT_A, 75, 360, 0, false, true); } }}

task move (){ while (bullets_remaining > 0) { // Do a random turn if (0 == Random (2)) { // Left turn OnFwd (OUT_B, 75); OnRev (OUT_C, 75); Wait (Random (TURN_TIME)); Off (OUT_BC); Wait (1000); fire = true; Wait (1000); } else { // Right turn OnFwd (OUT_C, 75); OnRev (OUT_B, 75); Wait (Random (TURN_TIME)); Off (OUT_BC); Wait (1000); fire = true; Wait (1000); } }

}

task main (){ // Make these tasks execute simultaneously after main () is finished Precedes (flashing_lights, shoot, move);}

Test guide

Download the program. Place the Shooterbot in the middle of the test pad and run the program.

4. Locate objects

Building guide

Can you build the Shooterbot to protect your room? You will have to add the Ultrasonic Sensor to your Shooterbot.



Programming guide

Can you program the Shooterbot to scan your room and detect objects? If an object is closer than 40cm, the

Shooterbot should shine a warning light and then shoot if the object does not move away.

// shooterbot_4.nxc// If an object is to close, shine a warning light and then shoot if// the object does not move away.

#define BULLETS 7#define FLASH_DURATION 200#define THRESHOLD 40#define WARNING_TIME 4000

#define start_turning(power) OnFwd (OUT_C, power); OnRev (OUT_B, power);

task main ()



task main (){ long t0; int bullets_remaining = BULLETS;

SetSensorLowspeed (S4); // Bring the ultrasonic sensor on-line SetSensorColorGreen (S3); // Set the lamp to show all-clear

while (bullets_remaining > 0) { start_turning (50); until (SensorUS (S4) < THRESHOLD); // Scan for close objects Off (OUT_BC); // Stop turning t0 = CurrentTick ();

while ((CurrentTick () - t0) < WARNING_TIME) { // Emit the warning - a flashing red lamp SetSensorColorNone (S3); Wait (FLASH_DURATION); SetSensorColorRed (S3); Wait (FLASH_DURATION); }

if (SensorUS (S4) < THRESHOLD) { bullets_remaining--; RotateMotorEx (OUT_A, 75, 360, 0, false, true); // Shoot Wait (1000); // Give motor A time to shoot }

SetSensorColorGreen (S3); // Set the lamp to show all-clear }

Off (OUT_BC); // Stop turning TextOut (8, LCD_LINE4, "OUT OF BULLETS", true); Wait (7000); StopAllTasks (); // Stop the program}

Test guide

Download the program. Place the Shooterbot in the middle of the test pad and run the program.

Robogator

Can you build and program a Robogator that attacks objects and protects its territory?

1. Jaws

Building guide

Can you build a robot with jaws that open and close?



















Programming guide

Can you program your robot to open and close its jaws?

// robogator_1.nxc// Open and close the jaws

// Sample the motor rotation speed every this number of milliseconds#define ROTATION_SAMPLE_RESOLUTION 50

// The approximate 'degrees per second' rotation of motor Along dps_a = 0;

task motor_speed_monitor (){ long mrc_a_0, mrc_a_1; // mrc == motor rotation count unsigned long t_a_0, t_a_1;



while (true) { // Record the rotation count and the time mrc_a_0 = MotorRotationCount (OUT_A); t_a_0 = CurrentTick ();

Wait (ROTATION_SAMPLE_RESOLUTION);

// Again, record the rotation count and the time mrc_a_1 = MotorRotationCount (OUT_A); t_a_1 = CurrentTick ();

// Calculate the average rotation rate over that time interval dps_a = ((mrc_a_1 - mrc_a_0) * 1000) / (t_a_1 - t_a_0); }}

task bite (){ while (true) { // Assume the jaws are closed to begin with - open them OnFwd (OUT_A, 40); Wait (100); // Wait > ROTATION_SAMPLE_RESOLUTION until (10 > dps_a); // Wait until the jaws have opened and are practically still Off (OUT_A);

// Close the jaws OnRev (OUT_A, 40); Wait (100); until (-10 < dps_a); // Reverse rotations are negative Off (OUT_A); }}

task main (){ Precedes (bite, motor_speed_monitor);}

Test guide

Download and run the program. Your Robogator jaws should open and close.

2. Eyes

Building guide

Can you make your Robogator see objects and attack them if they get too close?





Programming guide

Can you program your robot to bite when objects get too close?

// robogator_2.nxc// Open and close the jaws when objects are close


// Bite objects which come closer than this#define THRESHOLD 40


task motor_speed_monitor ()

{



{ long mrc_a_0, mrc_a_1; // mrc == motor rotation count unsigned long t_a_0, t_a_1;

while (true) { mrc_a_0 = MotorRotationCount (OUT_A); t_a_0 = CurrentTick ();


mrc_a_1 = MotorRotationCount (OUT_A); t_a_1 = CurrentTick ();

dps_a = ((mrc_a_1 - mrc_a_0) * 1000) / (t_a_1 - t_a_0); }}

task bite (){ SetSensorLowspeed (S4); // Bring the ultrasonic sensor on-line

while (true) { until (SensorUS (S4) < THRESHOLD); // Scan for close objects

// Assume the jaws are closed to begin with - open them OnFwd (OUT_A, 40); Wait (100); // Wait > ROTATION_SAMPLE_RESOLUTION until (10 > dps_a); // Wait until the motor stops Off (OUT_A);

// Close the jaws OnRev (OUT_A, 40); Wait (100); until (-10 < dps_a); // Reverse rotations are negative Off (OUT_A); }}

task main (){ Precedes (bite, motor_speed_monitor);}

Test guide

Download and run the program. Move your hand towards the Robogator's eyes. The Robogator's jaws shouldstart biting. Move your hand away and the Robogator should stop biting.

3. Legs

Building guide

Can you build a robot that can walk?





























































Programming guide

Can you program the Robogator to walk forward and start biting when objects get too close?

// robogator_3.nxc// Open and close the jaws and walk forward when objects are close



// Walk forward for up to this many steps when an object is close#define MAX_STEPS_FORWARD 3







task bite (){ while (true) { until (SensorUS (S4) < THRESHOLD); // Scan for close objects

// Assume the jaws are closed to begin with OnFwd (OUT_A, 40); Wait (100); // Wait > ROTATION_SAMPLE_RESOLUTION until (10 > dps_a); // Wait until the motor stops Off (OUT_A);

OnRev (OUT_A, 40); Wait (100);



OnRev (OUT_A, 40); Wait (100); until (-10 < dps_a); // Reverse rotations are negative Off (OUT_A); }}

task walk (){ int steps;

while (true) { until (SensorUS (S4) < THRESHOLD); // Scan for close objects

// Walk forward while an object is close steps = 0; while (SensorUS (S4) < THRESHOLD && steps < MAX_STEPS_FORWARD) { RotateMotorEx (OUT_BC, -100, 360, 0, true, true); steps += 1; } }}

task main (){ SetSensorLowspeed (S4); // Bring the ultrasonic sensor on-line

Precedes (bite, motor_speed_monitor, walk);}

Test guide

Download the program. Place your alligator on the test pad and run the program.

4. Tail

Building guide

Can you build the tail and add sensors to the Robogator so it knows where its legs are?

















Programming guide

Can you program Robogator to protect its territory: lunge forward, bite, and crawl back?

// robogator_4.nxc// When an object is close: open and close the jaws, walk forward,// and then move back



// Walk forward for up to this many steps when an object is close#define MAX_STEPS_FORWARD 3

// The approximate 'degrees per second' rotation of motor A









task bite (){ while (true) { until (SensorUS (S4) < THRESHOLD); // Scan for close objects

// Assume the jaws are closed to begin with OnFwd (OUT_A, 40); Wait (100); // Wait > ROTATION_SAMPLE_RESOLUTION until (10 > dps_a); // Wait until the motor stops Off (OUT_A); OnRev (OUT_A, 40); Wait (100); until (-10 < dps_a); // Reverse rotations are negative Off (OUT_A); }}

task walk (){ int i, steps;

// Use the touch sensors to align the legs initially OnFwd (OUT_B, -100); until (1 == SENSOR_1); Off (OUT_B); RotateMotor (OUT_B, -100, 45);

OnFwd (OUT_C, -100); until (1 == SENSOR_2); Off (OUT_C); RotateMotor (OUT_C, -100, 45);

while (true) { // Walk forward while an object is close steps = 0; while (SensorUS (S4) < THRESHOLD && steps < MAX_STEPS_FORWARD) { RotateMotorEx (OUT_BC, -100, 360, 0, true, true); steps += 1; }

// Walk back to the original position Wait (1000); while (steps > 0) { RotateMotorEx (OUT_BC, 90, 360, 0, true, true); steps -= 1; } }

}

task main (){ SetSensorLowspeed (S4); // Bring the ultrasonic sensor on-line SetSensorTouch (S1); // Bring the touch sensors on-line SetSensorTouch (S2);



Precedes (bite, motor_speed_monitor, walk);}

Test guide

Download the program. Place Robogator on the test pad and run the program.

Color Sorter

Can you build and program the Color Sorter to sort balls by color?

1. Dispenser

Building guide

Can you build a dispenser that separates balls one by one?































































































Programming guide

Can you program the dispenser to tilt and dispense one ball at a time?

// colorsorter_1.nxc// Dispense one ball at a time

// The number of balls to be sorted#define BALLS 4

// Get the dispenser in a standard positionvoid reset_dispenser (){ OnRev (OUT_B, 80); until (1 == SENSOR_1); Off (OUT_B); Wait (1000);}

// Dispense one ballvoid dispense_ball (){ reset_dispenser (); RotateMotor (OUT_B, 60, 720); Wait (1000);}

task main (){ int i;

// Bring the tilting mechanism's touch sensor on-line SetSensorTouch (S1);

i = 0; while (i++ < BALLS) { dispense_ball (); }

}

Test guide



Download your program. Place the Color Sorter in the middle of the test pad. Put a couple of balls in thedispenser and run the program.

2. Color detector

Building guide

Can you build a color detector that can recognise the different ball colors?





Programming guide

Can you make a program that can tell the difference between the colors of the balls?

// colorsorter_2.nxc// Dispense one ball at a time - display the color of each ball

// The number of balls to be sorted#define BALLS 4

// Get the dispenser in a standard positionvoid reset_dispenser (){ OnRev (OUT_B, 80); until (1 == SENSOR_1); Off (OUT_B); Wait (1000);

}

}

// Get a ball into the dispenser slotvoid load_ball (){ RotateMotor (OUT_B, 60, 360); Wait (1000);}

void dispense_ball (){ RotateMotor (OUT_B, 60, 360); Wait (1000);}

void show_color (){ string ball_color = "";

switch (SENSOR_3) { case INPUT_BLUECOLOR: ball_color = "BLUE"; break; case INPUT_REDCOLOR: ball_color = "RED"; break; case INPUT_GREENCOLOR: ball_color = "GREEN"; break; case INPUT_YELLOWCOLOR: ball_color = "YELLOW"; break; default: ball_color = "NONE"; break; }

// Show the ball color TextOut (30, LCD_LINE3, ball_color, true); Wait (1000);}

task main (){ int i;

// Bring the tilting mechanism's touch sensor on-line SetSensorTouch (S1);


i = 0; while (i++ < BALLS) { // Show the number of balls left to sort TextOut (0, LCD_LINE1, "Balls remaining: ", true); NumOut (50, LCD_LINE3, BALLS - (i-1));

reset_dispenser (); load_ball (); show_color (); dispense_ball (); }

}

Test guide

Download your program. Place the Color Sorter in the middle of the test pad. Run the program.

3. Sorting tray

Building guide

Can you build a sorting tray that allows the Color Sorter to sort the four different colored balls into their own

basket?

















Programming guide

Can you program the sorting tray to spin around and place balls of the same color in the same basket?

// colorsorter_3.nxc// Place balls of the same color in the same basket

// Assume there are no balls remaining after this number of retries#define RETRIES 2

// Reset the dispensing tray and the basket when these are set to truebool reset_dispenser_flag = false;bool reset_basket_flag = false;

// Get a ball into the dispenser slotvoid load_ball (){

Wait (2000);



Wait (2000); // Shake up the balls in the dispenser RotateMotor (OUT_B, 90, 400); RotateMotor (OUT_B, -90, 400); Wait (500);}

void dispense_ball (){ RotateMotor (OUT_B, -90, 360); Wait (1000);}

// Show the color of the ball on the NXT display// Return the value of the color of the ball to the calling taskstring show_color (){ string ball_color = "";


// Show the ball color TextOut (30, LCD_LINE3, ball_color, true); Wait (500);

return ball_color;}

void align_basket (string ball_color){ // RED, YELLOW, GREEN, BLUE if (ball_color == "YELLOW") { RotateMotor (OUT_C, 30, 90); }else if (ball_color == "GREEN") { RotateMotor (OUT_C, 30, 180); }else if (ball_color == "BLUE") { RotateMotor (OUT_C, -30, 90); }}

// Get the dispenser in a standard positiontask reset_dispenser (){ while (true) { if (true == reset_dispenser_flag) { // Get the dispenser into a standard position using the touch sensor OnRev (OUT_B, 80); until (1 == SENSOR_1); Off (OUT_B); reset_dispenser_flag = false; } }}

task reset_basket (){ while (true)



{ if (true == reset_basket_flag) { // Get the basket into a standard position using the touch sensor OnFwd (OUT_C, 30); until (0 == SENSOR_2); // Unset the touch sensor if it is set until (1 == SENSOR_2); Off (OUT_C); RotateMotor (OUT_C, -30, 30); reset_basket_flag = false; } }}

task main (){ int i; string ball_color;

// Bring the tilting mechanism's touch sensor on-line SetSensorTouch (S1); // Bring the sorting mechanism's touch sensor on-line SetSensorTouch (S2);


StartTask (reset_basket); StartTask (reset_dispenser);

while (true) { // Clear the display ResetScreen ();

i = 0; do { // Reset the positions of the dispenser and the baskets in parallel reset_dispenser_flag = true; reset_basket_flag = true;

// Wait until the reset tasks are both finished until (false == reset_dispenser_flag && false == reset_basket_flag);

load_ball (); // Place a ball in the dispenser exit slot ball_color = show_color ();

// Check for a ball in the dispenser exit slot } while (++i < RETRIES && "NONE" == ball_color)

if ("NONE" == ball_color) { // Assume no balls are remaining TextOut (0, LCD_LINE3, "*** FINISHED ***", true); Wait (4000); break; }

align_basket (ball_color); dispense_ball (); }

StopAllTasks ();}

Test guide

Download your program. Place the Color Sorter in the middle of the test pad. Run the program.

4. Color catapult

Building guide



Can you build a color catapult that throws balls in different directions?

















Programming guide

Can you program the color catapult to throw balls of the same color in the same direction?

// colorsorter_4.nxc// Chuck balls of the same color in the same direction

// Assume there are no balls remaining after this number of retries#define RETRIES 2

// Reset the dispensing tray and the catapult when these are set to truebool reset_dispenser_flag = false;bool reset_catapult_flag = false;

// Get a ball into the dispenser slotvoid load_ball (){

Wait (2000);



Wait (2000); // Shake up the balls in the dispenser RotateMotor (OUT_B, 90, 400); RotateMotor (OUT_B, -90, 400); Wait (500);}

void dispense_ball (){ RotateMotor (OUT_B, -90, 360); Wait (1000);}

// Show the color of the ball on the NXT display// Return the value of the color of the ball to the calling taskstring show_color (){ string ball_color = "";


// Show the ball color TextOut (30, LCD_LINE3, ball_color, true); Wait (500);

return ball_color;}

void align_catapult (string ball_color){ // RED, YELLOW, GREEN, BLUE if (ball_color == "RED") { RotateMotor (OUT_C, 30, 45); }else if (ball_color == "YELLOW") { RotateMotor (OUT_C, 30, 90); }else if (ball_color == "GREEN") { RotateMotor (OUT_C, -30, 45); }else if (ball_color == "BLUE") { RotateMotor (OUT_C, -30, 90); }}

// Get the dispenser in a standard positiontask reset_dispenser (){ while (true) { if (true == reset_dispenser_flag) { // Get the dispenser into a standard position using the touch sensor OnRev (OUT_B, 80); until (1 == SENSOR_1); Off (OUT_B); reset_dispenser_flag = false; } }}

task reset_catapult ()



{ while (true) { if (true == reset_catapult_flag) { // Get the catapult into a standard position using the touch sensor OnFwd (OUT_C, 30); // Unset the touch sensor if it is set by moving toward the front side until (0 == SENSOR_2);

OnFwd (OUT_C, -30); // Move back until the touch sensor activates until (1 == SENSOR_2); Off (OUT_C);

RotateMotor (OUT_C, -30, 15); // A slight adjustment for perfect alignment reset_catapult_flag = false; } }}

task main (){ int i; string ball_color;

// Bring the tilting mechanism's touch sensor on-line SetSensorTouch (S1); // Bring the sorting mechanism's touch sensor on-line SetSensorTouch (S2);


StartTask (reset_catapult); StartTask (reset_dispenser);

while (true) { // Clear the display ResetScreen ();

i = 0; do { // Reset the positions of the dispenser and the catapult in parallel reset_dispenser_flag = true; reset_catapult_flag = true;

// Wait until the reset tasks are both finished until (false == reset_dispenser_flag && false == reset_catapult_flag);

load_ball (); // Place a ball in the dispenser exit slot ball_color = show_color ();

// Check for a ball in the dispenser exit slot } while (++i < RETRIES && "NONE" == ball_color)

if ("NONE" == ball_color) { // Assume no balls are remaining TextOut (0, LCD_LINE3, "*** FINISHED ***", true); Wait (4000); break; }

dispense_ball (); align_catapult (ball_color);

// Fire the catapult OnFwd (OUT_A, 100); Wait (500); Off (OUT_A); OnFwd (OUT_A, -100); Wait (500); Off (OUT_A);

// Move the catapult back over to the front side, ready for resetting its position if (ball_color == "GREEN") { RotateMotor (OUT_C, 30, 45+90); }else if (ball_color == "BLUE") { RotateMotor (OUT_C, 30, 90+90);



}

}

StopAllTasks ();}

Test guide

Download your program. Place the Color Sorter in the middle of the test pad and make sure the axle isplaced in the centre. Run the program.

Alpha Rex

Can you build and program the Alpha Rex to walk?

1. Legs

Building guide

Can you build a pair of legs that can walk?































































Programming guide

Can you build a pair of legs that test walk in place, and then walk forwards and backwards?

// alpharex_1.nxc// Walk in place, and forwards, and backwards.

// Three directions for walking#define INPLACE 0#define FORWARDS 1#define BACKWARDS 2

// Get the legs in a standard position// Motor B & touch sensor 1 ---> right leg// Motor C & touch sensor 2 ---> left legvoid reset_legs ()

{



{ if (1 == SENSOR_1) { OnFwd (OUT_B, 50); Wait (300); until (0 == SENSOR_1); Off (OUT_B); } OnFwd (OUT_B, 50); until (1 == SENSOR_1); Off (OUT_B);

if (1 == SENSOR_2) { OnFwd (OUT_C, 50); Wait (300); until (0 == SENSOR_2); Off (OUT_C); } OnFwd (OUT_C, 50); until (1 == SENSOR_2); Off (OUT_C);}

void walk (int direction, unsigned long duration){ unsigned long t0;

reset_legs (); Wait (2000);

RotateMotor (OUT_B, 70, 45); // Put right leg down RotateMotor (OUT_C, -70, 150); // Put left leg up

t0 = CurrentTick ();

switch (direction) { case INPLACE:

while (CurrentTick () - t0 < duration) { OnFwd (OUT_B, 70); OnFwd (OUT_C, -70); } break;

case FORWARDS:

while (CurrentTick () - t0 < duration) { OnFwdSync (OUT_BC, 50, 0); } break;

case BACKWARDS:

while (CurrentTick () - t0 < duration) { OnRevSync (OUT_BC, 50, 0); } break; }

Off (OUT_BC);}

task main (){ // Bring the touch sensors on-line SetSensorTouch (S1); SetSensorTouch (S2);

walk (INPLACE, 5000); Wait (2000); walk (BACKWARDS, 5000); Wait (2000); walk (FORWARDS, 5000); Wait (2000);

}



Test guide

Download the program. Place the Alpha Rex on the test pad. Run the program.

2. Arms

Building guide

Can you build the Alpha Rex with a pair of arms and moveable hands?















































Programming guide

Can you program the arms to move back and forth while the hands open and close?

// alpharex_2.nxc// Move the arms back and forth

task main (){ while (true) { // turn right - open left hand RotateMotor (OUT_A, 100, 2*60);

// back to center RotateMotor (OUT_A, -100, 2*60);

Wait (1000);

// turn left - open right hand RotateMotor (OUT_A, -100, 2*60);

// back to center RotateMotor (OUT_A, 100, 2*60);

Wait (1000); }}

Test guide


3. Head

Building guide

Can you build the Alpha Rex to see? You will have to build a head on it!















Programming guide

Can you program the Alpha Rex to move forward when it sees an object?

// alpharex_3.nxc// Move forward when an object is visible

// Walk forward when objects come closer than this#define THRESHOLD 50

// Three directions for walking#define INPLACE 0#define FORWARDS 1#define BACKWARDS 2

// Get the legs in a standard position// Motor B & touch sensor 1 ---> right leg// Motor C & touch sensor 2 ---> left legvoid reset_legs (){ if (1 == SENSOR_1) { OnFwd (OUT_B, 50); Wait (300); until (0 == SENSOR_1); Off (OUT_B); } OnFwd (OUT_B, 50); until (1 == SENSOR_1); Off (OUT_B);



RotateMotor (OUT_B, 70, 45); // Put right leg down




OnFwd (OUT_B, 50); OnFwd (OUT_C, -50); until (CurrentTick () - t0 > duration); break;

case FORWARDS:

OnFwdSync (OUT_BC, 50, 0); until (CurrentTick () - t0 > duration); break;

case BACKWARDS:

OnRevSync (OUT_BC, 50, 0); until (CurrentTick () - t0 > duration); break; }

Off (OUT_BC); reset_legs ();}

task main (){ SetSensorTouch (S1); SetSensorTouch (S2); // Bring the touch sensors on-line

SetSensorLowspeed (S4); // Bring the ultrasonic sensor on-line


while (true) { until (SensorUS (S4) < THRESHOLD); walk (FORWARDS, 5000); Wait (2000); }

}

Test guide


4. Color sensor

Building guide

Can you make the Alpha Rex detect colors by adding the Color Sensor?



Programming guide

Can you program the Alpha Rex to ask for the green ball and then identify it? The Alpha Rex should identify andreject balls in other colors.

// alpharex_4.nxc// Ask for a green ball

// TODO Use a voice to ask for a green ball when nxc adds// support for sound files on Linux

// Ask for a ball when an object is closer than this#define THRESHOLD 50

// Three directions for walking#define INPLACE 0

#define FORWARDS 1



#define FORWARDS 1#define BACKWARDS 2

void drop_ball (){ RotateMotor (OUT_A, -100, 2*60); Wait (800); // back to center RotateMotor (OUT_A, 100, 2*60);}

// Get the legs in a standard position// Motor B & touch sensor 1 ---> right leg// Motor C & touch sensor 2 ---> left legvoid reset_legs (){ if (1 == SENSOR_1) { OnFwd (OUT_B, 50); Wait (300); until (0 == SENSOR_1); Off (OUT_B); } OnFwd (OUT_B, 50); until (1 == SENSOR_1); Off (OUT_B);






OnFwd (OUT_B, 50); OnFwd (OUT_C, -50); until (CurrentTick () - t0 > duration); break;

case FORWARDS:

OnFwdSync (OUT_BC, 50, 0); until (CurrentTick () - t0 > duration); break;

case BACKWARDS:

OnRevSync (OUT_BC, 50, 0); until (CurrentTick () - t0 > duration); break; }

Off (OUT_BC); reset_legs ();}

task main (){ SetSensorTouch (S1); SetSensorTouch (S2); // Bring the touch sensors on-line SetSensorLowspeed (S4); // Bring the ultrasonic sensor on-line SetSensorColorFull (S3); // Bring the color sensor on-line




while (true) { until (SensorUS (S4) < THRESHOLD);

// Display a message TextOut (0, LCD_LINE1, " GIVE ME A ", true); TextOut (0, LCD_LINE3, " *** GREEN *** ", false); TextOut (0, LCD_LINE5, " BALL ", false);

// Wait until a ball is placed in the right hand until (INPUT_BLACKCOLOR != SENSOR_3);

Wait (2000); ResetScreen ();

if (INPUT_GREENCOLOR == SENSOR_3) { // Do a dance walk (INPLACE, 5000); // Release the ball drop_ball (); } else { // Move forward walk (FORWARDS, 5000); // Drop the ball drop_ball (); // Move back walk (BACKWARDS, 5000); }

Wait (1000); }}

Test guide

Download the program. Place the Alpha Rex on the test pad. Before running the program, the Alpha Rex'shands should be closed and pointed forward (do this by turning the gear on the right side of its back). Run theprogram.

Documents

NXT 2.0 Instructions