Robotics: NXT, Programming - Universiteit Twente · Robotics: NXT, Programming ... Textual commentary: what program is doing (do this!) 18 . Programming NXT ... Robot examples 47

15-9-2015 1

HTHT Science 2 Society Minor Module 1: From Idea to Prototype

Robotics: NXT, Programming

Prof. Frank van der Velde

Cognitive Psychology

& Ergonomics (CPE)

CTIT

Overview

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Mindstorms NXT 2.0: • Robot types • Programming • Installation

21 September: Ing Fjodor van Slooten will give a hands-on lecture on the NXT IO (Application Development and Design) Horstring Noord, N208 ([email protected]) (This lecture is strongly based on his presentations) At another time: Dr. Vicky Charisi will present a one-hour talk on child-robot interaction.

What is Lego Mindstorms NXT 2.0?

Technical Lego + “Computer” + Sensors + Actuators

Different robot types possible

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Brick

Lego Brick NXT

Ports for motors

Ports for sensors

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Lego Brick NXT

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256 Kb memory Display 100x64 Speaker

Lego Brick NXT

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Battery: will be empty Charge battery at least 30 min Continue charging battery during session.

Sensors NXT

Licht sensor Detects light intensity environment And reflection infrared sender

Ultrasonic sensor Determines distances with ultrasound waves

Sound sensor Records sound level (not microphone!)

Touch sensor Responds to: Pressing Release Touch

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start

Ultrasonic sensor NXT

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Ultrasonic sensor does not always operate on port 4! Sensor value is visible when

NXT is linked.

Color sensors NXT

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Lego ColorSensor

HiTechnicColorSensor

RGB

Servo Motors NXT

Tachometer for build-in Rotation

Sensor Motor core Build-in gearing

Attaching a wheel

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Programming NXT

Drag and drop programming 11

Programming NXT


Common: • Move • Record/Play • Sound • Display • Wait • Loop • Switch

Programming NXT


Action: • Motor • Sound • Display • Send message • Color lamp

Programming NXT


Sensor: • Touch • Sound • Light • Ultrasonic • NXT button • Rotation • Timer • Receive message • Color sensor

Programming NXT


Flow: • Wait • Loop • Switch • Stop

Programming NXT


Data: • Logic • Math • Compare • Range • Random • Variable • Constant

Programming NXT


Advanced: • Number to text • Text • Keep alive • File access • Calibrate • Reset motor • Bluetooth connection

Programming NXT

Example: (see “educatieve_bijlage_nxt_binnenstebuiten.pdf”)

Configuration screen:

start

Textual commentary: what program is doing (do this!) 18

Programming NXT



start Wait 2 sec

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Programming NXT


start Wait 2 sec


Move forward

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Programming NXT


start Wait 2 sec


Move forward Move backward

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Programming NXT


start Wait 2 sec Move forward Move backward

Store program

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Programming NXT


Transferring program to brick (PC and NXT need to be linked)

Using either: • USB • Bluetooth

Download and start program

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Stop

Programming NXT


Repeating program parts is usually not good programming!

Repeat program 3 times:

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Programming NXT


Instead, use a ‘loop’ by inserting repeat block


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Programming NXT

Help gives information on programming

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Programming NXT Example: present sensor values on screen

• (Light) sensor block • Number-to-Text block • Display block

Then: Connection with Data Wire

After that: place in Loop

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Programming NXT Example: present sensor values on screen

Loop (Infinite)

Complete palette

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Programming NXT Example: move along wall

Steering parameter gets result calculation

First:

Robot moves straight ahead?

Tip: drive slowly, need time for processing sensor information.

NXT button

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Programming NXT

Example: avoiding collision (Bumper car)

Yes: drive back a bit and make turn (try other direction)

Is Touch sensor pressed? Driving straight ahead

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Programming NXT

Example: using NXT buttons

Switch block (conditional, if .. then)

Condition: True or False

True

False

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Programming NXT

Example: wait until Enter button is pressed

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Programming NXT

Example: using variables

Menu: Edit > Manage variables Variabele name, type

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Programming NXT

Example: using variables

Advanced example

Decision: is TurnOn True?

Value variable enters Decision via data wire

TurnOn=False

MotorRunning=True

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Programming NXT

Example: multiple tasks

• Tasks in sequence • Disadvantage: if something happens in one task, it could be ignored in other

Task 1 Task 2

Loop

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Programming NXT

Example: multiple tasks

• Tasks simultanously • Disadvantage: programming more difficult • E.g., cannot just use same sensor • Solution: variables

Task 1

Task 2 Pull ends to make connections

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Programming NXT

Example: using timer

There are 3 timers. Start with 0 at beginning of program

Have 5 sec passed?

Reset timer

Timer 1

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Programming NXT


Is someone gone for longer as 30 sec?

Task 1

Reset timer if close So, timer runs as long as far away

Keep repeating loop

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Programming NXT


Is someone gone for longer as 30 sec?

Task 1

Use result (logical) comparison to see if timer has ‘turned on’ (if 30 sec have passed)

Reset timer

Task 2 Keep repeating loop

Timer passed: play sound

and reset timer

Programming NXT

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For using Lego software: Possibly Java firmware installed on NXT Install also Lego Firmware on NXT Zip-file, map lego\firmware\1.31 See INSTALLATIE.TXT

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Programming NXT

More complicated and flexible programming: • Use programming language LeJOS. • Based on JAVA, suited for NXT

Software and documentation can be found on Website APPLICATIEBOUW http://module4.io.utwente.nl/applicatiebouw/

Lectures (Dutch)

Download

http://module4.io.utwente.nl/applicatiebouw/





Programming NXT

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Download: http://module4.io.utwente.nl/applicatiebouw/index.php?dir=download

Installation instructions and zip file

Zip file (> 1 GB)

Unpack zip file

See info:

http://module4.io.utwente.nl/applicatiebouw/index.php?dir=download







Programming NXT

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Unpack zip file

See info:

Programming NXT

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Unpack zip file

See info:

Building robots

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Unpack zip file

See info:

Lego parts:

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Unpack zip file

See info:

Working with Lego parts:

Lego parts: Box Box is owned by the UT. Use is carefully! Use lock for the box! Check content of box Fill in list: http://module4.io.utwente.nl/aftekenlijst/ If parts are missing: Mail Fjodor van Slooten

Building robots

http://module4.io.utwente.nl/aftekenlijst/





Robot examples

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Unpack zip file

See info:

Ultrasonic sensor: detects object

Instructions for building this robot

Sound sensor: reacts to commands

Touch sensor: detects object

between claws

Claws to grasp and transport

object

Light sensor: stay within area

Robot examples

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Castor Bot

Instructions for building this robot: nxtprograms.com

Robot examples

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Castor Bot


Robot examples

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Castor Bot


Simple design

Extra sensors can be

added easily

Two separately

driving wheels

Assistance wheel

Robot examples

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Robot Arm


Robot examples

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Turns around

an axis

Moves up and down

Robot Gripper: Grabbing and moving object

Light sensor detects colour of object

Claw can open and close

Touch sensor detects presence of object

Robot examples

Information about robots can be found in: • In Lego software: building guides • Zip file Applicatiebouw • nxtprograms.com • Books (contact Fjodor van Slooten,

Horstring Noord, N208 ([email protected])

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Installation of programmes

See: See: “Installatie” (For Mac and Windows) Windows: Start script install.bat by right clicking mouse. Choose Run as Administrator. You need the following programmes (in this order!) - Java Development Kit (JDK), 32 bits versie - Eclipse IDE for Java Developers, 32 bits versie - Lego Mindstorms NXT software - LeJOS - Eclipse plugin voor LeJOS


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Java Development Kit (JDK) Go to Unpacket Zip map To map 'Java'. Dubbelclick on: jdk-8u45-windows-i586.exe Wizard installs JDK and Java Runtime environment (JRE, version 8) Installation via Next (a number of times) Close


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Eclipse: IDE


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Eclipse: IDE

Eclipse can run without installation For this copy the folder Eclipse to: "C:\Program Files (x86)" or "C:\Program Files". Doubleclick on Eclipse to see its content Click on file “eclipse.exe”with right mousebutton Select "Send to > Desktop (create shortcut)"


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Start Eclipse: First time program asks for making a Workspace Use your Documents folder "Make New folder". Give distinctive name eg. “EclipseWorkspace”. Activate option "Use this as the default ..." OK.


After OK:

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You can click this away to start using Eclipse


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Lego Mindstorms NXT software Start by activating setup.exe in folder 'Lego\LegoMindstorms2.0'. Ignore ‘wrong Windows-version’ or ‘lack of memory’ (continue with Next) After installation install 2 updates: Install first patch 2.0f3 in folder Lego\2.0f3_patch via setup.exe in that folder. Install latest version Lego Mindstorms NXT driver in folder Lego\driver_1.1.3 via setup.exe in that folder


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LeJOS installation: Remove old version with uninstall.exe (then restart computer) Driver of Lego Mindstorms NXT must be installed (see previous slide) Installation of LeJOS: doubleclick leJOS_NXJ_0.9.1beta-3_win32_setup.exe in folder 'LeJOS' After Next select Java Development Kit. Select latest version (jdk1.7.0_51 or higher).


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LeJOS installation: Location: standard Continue with Next


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LeJOS installation: Select "Sample and Example Projects" Leave other options as they are Continue with Next.


LeJOS installation: In other screens leave it as it is. Continue with Next (a number of times) Press Install to start installation.

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LeJOS installation: After installation start NXJ Flash utility by selecting "Launch NXJ Flash utility" Press Finish If LeJOS firmware is not on NXT, install with NXJ Flash utility: Connect NXT to computer and turn it on Wait until driver is installed. Press button 'Flash LeJOS firmware'. After 'Ok' en 'Yes' LeJOS firmware is installed on NXT More information (Dutch) In file TIPS.txt (in folder 'LeJOS‘)


Eclipse plugin for LeJOS Is ‘enclosed’ in Eclipse (based on ZIP-file Applicatiebouw) Hence installation of the plugin is not needed. Ckeck and control the options of the Eclipse plugin for LeJOS: Select in Eclipse: Window > Preferences from menu Then select "LeJOS NXJ". If under NXJ_HOME you find the folder where LeJOS geinstalleerd is installed, the plugin is fine.

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Eclipse plugin for LeJOS Otherwise: Browse to find path to LeJOS (NXJ_HOME). This is folder where LeJOS is installed. Is usually: C:\Program Files\LeJOS NXJ or C:\Program Files (x86)\LeJOS NXJ

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Eclipse plugin for LeJOS After installation you find the LeJOS icon in menu bar of Eclipse

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New LeJOS project in Eclipse

See: http://www.lejos.org/nxt/nxj/tutorial/Preliminaries/UsingEclipse.htm

Go the "File" menu of Eclipse and select "New" and then "Project...""

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See: http://www.lejos.org/nxt/nxj/tutorial/Preliminaries/UsingEclipse.htm

Then:

Two options:

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This opens the wizard for creating new leJOS PC projects:

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Enter name e.g., NewPCProject (but use more informative names for yourself) Press Finish


In Eclipse, you will see your new project: NewPCProject And JAR files from Libraries (JAR: Java Archive)

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Right click the src folder and select "New" and then "Class" in the context menu

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"Src“: folder where the project's source files are located. In a Java project, src folder and its sub folders hold the .java files.


This opens the wizard for creating new Java classes

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Press Finish: Editor opens You can type in program

The package name com.mydomain (lowercase!) corresponds to the DNS domain "mydomain.com". Make sure to chose appropriate names.

Source folder name: NewPCProject

Package name (= namespace)

File name: HelloWorld


Example program ”HelloWorld.java”

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Notice order: • package

• import (if any)

• class

• void main

Appear when opening file (except import) File name = class name + .java



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Run program: right-click on the class which contains the main method. Select "Run As"→"Java Application" in the context menu.



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Run program: Output on the local console in Eclipse.