Tufts Datalogging Book 1

7/30/2019 Tufts Datalogging Book 1

1/34

Find the Light Book DI: NXT Data LoggingLevel 1

Copyright 2009 Tufts University Center for Engineering Education and Outreach

LEGO Engineering Conferences

ROBOLAB and MINDSTORMS EducationVersion 5.0 December 2009

NXT-G Data Logging Book I: Introductory

Robotic Activities for use with the NXT


2/34


Copyright 2009 Tufts University Center for Engineering Education and OutreachD1 - 1

NXT Data Logging Book DI: Introductory

Data Logging Activities for use with the NXT

This purpose of this book is to help you develop a basic understanding of how to collectand graph data using the LEGO MINDSTORMS program and the NXT brick. Each

activity in this book contains learning objectives and step-by-step programminginstructions that illustrate how to conduct data logging experiments. At the end of each

activity, an open-ended Exploration Taskprovides you with the opportunity to practicethe techniques you just learned.

In these introductory activities, the primary focus points include creating data logging

experiments, integrating data logging experiments into NXT programs, and displayingdata in the NXT Data Logging workspace. The Introductory activities involve collecting

data from the NXT touch sensor, NXT light sensor, NXT rotation sensor, and the NXTsound sensor.

Activities in this book assume that the user has experience programming with blocks inLEGO MINDSTORMS. You should also be able to modify the blocks using theconfiguration panel. If you do not have experience programming in LEGO

MINDSTORMS, please reviewNXT-G Software Book I: Introductory.

Activities Level Page

Finding the Light 1 DI - 2

Voting Booth 1 DI - 8

Measuring Wheel 2 DI - 14

Into the Dark 2 DI - 20

Hidden Letter 2 DI - 27

Additional Required Materials

These materials are not provided with the Conference Kits, and must be colletedseparately before attempting any of the activities in this workbook.

Materials Number

Meter or Yard stick 2

Roll of broad black tape (electrical tape) 3Roll of white tape 2

Pair of Scissors 1Power adaptor for charging NXT Brick 2

Large print-out of letters of the alphabet 1

Some sort of construction to hide a letter so that a data collector cannot see what theirNXT vehicle is driving over (chair covered by cloth, cardboard box tunnel, etc)


3/34



Level 1 Data Logging

Find the Light

Learning Objective:

Understand how to collect information from the light sensor using both the NXT brickand theNXT Data Loggingfeature in NXT MINDSTORMS v. 2.0.

Challenge:

In this challenge, you will be asked to use your NXT brick and a light sensor to collectlight sensor information. You will first use the view feature on your NXT to read light

levels in the room to become accustomed to using this sensor to collect data. This datawill be displayed numerically on your NXT screen. You will then attach your NXT and

light sensor to your computer to read light levels in the environment around yourcomputer. With data displayed graphically.

Building Procedure:

NOTE: This activity will not involve building an NXT vehicle.

Step 1: Using a wire, attach an NXT light sensor to your NXT brick via port 2.

Light Sensor:

Using the NXT

Step 1: Turn on the NXT by selecting the orange button. The NXT will turn on to show

the main menu.

Step 2: Using the grey arrow buttons, navigate through the menu until you see the view

icon.


4/34



Step 3: Select View by pressing the orange select button. You will be directed to a listof sensors. Navigate to the ambient light icon using the grey navigation buttons. Select

this menu option by pressing the orange select button.

Note: Ambient light measures the light levels in the environment around the light sensor.Reflected light measures the amount of light that is returned to the light sensor from light

that it generates itself. The Ambient Light option is what you should use when youwant to know about light levels surrounding the NXT. The Reflective Light option is

what to use to measure light reflected off of materials (darker, less shiny materials willnot reflect much light, whereas lighter, more reflective materials will reflect a lot of light)

Step 4: You will be directed to a menu of ports. Navigate to the correct port using the

grey arrow buttons. Select the correct port (input port 2) using the orange select button.

Step 5: At this point, you will be able to view the light levels that your light sensor is

measuring. Walk around the room to find the darkest spot you can and the lightest spotyou can. The NXT measures light levels on a scale of 0 100, with 0 being the darkest,

100 being the lightest.

Step 6:Notice the value of light in different areas of the room. You will useNXT dataloggingto measure light levels at your desk, so keep in mind the values to see if you can

replicate the highest and lowest values when sitting at your desk.

Programming Procedure:

Step 1: Open up NXT MINDSTORMS v. 2.0.

Step 2: Access the NXT Data Loggingmenu by clicking on the button at thetop of theNXT Programmingmenu.


5/34



Step 3: You will be directed to theNXT Data Loggingmenu shown below:

Step 4: Type the name of your experiment into theNXT Data Loggingmenu in the StartNew Experimenttitle box.

Step 5: Click the button to the right of the orange Start New Experimenttitlebox to continue.

Step 6: The Experiment Configuration panel will appear. You will be collecting light

sensor data from a light sensor wired to port 2, for 10 seconds, at a rate of 5 light sensorsamples a second. This will give you a total of 50 data points. Configure the experiment

as shown below:

Step 7: In the Experiment Configuration panel, the experiment will automatically look

for reflected light, for this experiment you want to collect ambient light data. To do this,uncheck the reflected light option in the experiment configuration panel. Shown below:

Step 8: TheNXT Data Logging workspace should now appear andlook similar to the image below:

Note: You are measuring light levelsin the environment, which is why you

want to measure ambient rather thanreflected light.


6/34



There are five main areas in the Data Logging workspace:

Area 1 The Data Logging toolbar, which contains tools for manipulating data.Area 2 The Navigation Space, used to select different experiment tabs.

Area 3 The Data Logging Graph, which displays collected data as line graphs.

Area 4 The Data Logging Controller, which allows for information transfer

between the computer and the NXT Brick.Area 5 The Dataset Table, which displays the collected data as numbers.

Data Collection:

Step 1: Attach your NXT brick to your computer via the USB cable.

Step 2: Now you are ready to run your experiment. To collect data, click on the play

button in the center of the Data Logging Controller at the lower right corner of your datalogging workspace (Area 4). This button will collect the data from your NXT brick as

you sit at your desk.


7/34



Step 3: While the experiment is running, examine the environment at your desk by

pointing your light sensor in different directions. Try to find the darkest and the lightestareas around your computer, can you replicate the numbers you got when you walked

around the room examining light sensor values on your NXT? Remember that you onlyhave 10 seconds to collect your data.

Data Analysis:

Step 1: Your graph should look similar to the graph shown below. The peaks will

indicate when the light sensor was in the lightest area(s) and the valleys indicate when thelight sensor was in the darkest area(s):

Step 2: To analyze your graph you can use the section analysis tool located in the toptoolbar:


8/34



Step 3: This tool will automatically place a section on your graph. Move the section by

selecting the left or right edges and dragging them to the spot that you want to start or endthe analysis. Use the section analysis tool to find the minimum value and maximum value

on your graph as shown below:

Step 4: You can also analyze your data in the data set table below your graph. You canlook at the amount of light the sensor was detecting at each interval of your experiment,

as shown below:

Further Experimentation:

Data logging allows you to collect and store information over a period of time. You canreconfigure this experiment to collect data on light levels over much longer periods of

time, say 24 hours. This type of experiment would show how the light levels in a roomwould change over the course of a day as the lights are turned on/off and as the sun goes

up and down.


9/34

Voting Booth Book DI: NXT Data LoggingLevel 1



Voting Booth

Learning Objective:

Understanding how to collect and analyze data from two touch sensors inNXT DataLogging.

Challenge:

In this challenge, you will write an experiment to collect data from two touch sensorswired to your NXT brick to make a voting booth. You will think of a yes/no question

for the group/class to vote on. Other people will vote on your question by pressing one oftwo sensors on your voting booth to give their answer(s). You will total the number of

votes by counting peaks on your graph.

Building Procedure:

Step 1: Think of a yes/no question that you would like to survey other people in the room

about. Write this question on an index card.

Step 2: Wire one touch sensor to port 1 on your NXT brick and label this sensor Yeswith a piece of masking tape or half of an index card. You should secure the sensor using

a beam and pegs so that it is mounted on one side of the NXT brick.

Step 3: Wire the other touch sensor to port 3. Secure the touch sensor to the other side of

your NXT brick using beams and pegs. Label this touch sensor No.


Step 1: Open up NXT MINDSTORMS v. 2.0. Click on the icon in the upper

left.

Whats your vote?

YES NO


10/34



Step 2: You will be directed to the Start Data Loggingwindow. Type the name of yourexperiment in the Start New Experimentbox.

Step 3: Click the button to the right of the orange Start New Experimenttitle

box to continue.

Step 4: The Experiment Configuration Panel will now appear. Configure the experiment

as shown below. You will be collecting data for 300 seconds at a rate of 5 samples persecond from two separate touch sensors, one wired to port 1 and the other to port 3.

Step 5: Click to proceed to the data logging workspace.

Data Collection:

Step 1: Connect your voting booth (NXT brick) to your computer via the USB cable.Step 2: You will leave your experiment at your computer while you walk around the

room to vote at other groups voting booths. Place your voting booth next to yourcomputer and set it up so that people can read the question on the index card and vote on

the question using your NXT voting machine while you are away.

Step 3: When everyone in the class is ready to vote, begin your experiment by clickingon the play button in the center of your data logging control panel at the lower rightcorner of the graphing space, as shown below:

Step 4: You will have 5 minutes (300 seconds) for your experiment to run, collecting

votes, while you vote on other groups questions. At the end of the 5 minutes, return toyour computer to analyze your data.

Data Analysis:

Step 1: Your graphs should look similar to the graph shown below. There should be twoseparate graphs, one for each sensor. A value of 1.0 indicates that the touch sensor was

depressed by someone voting on at your voting booth. It may be difficult to see thedifference between the two separate graphs.


11/34



Step 2: To make it easier to differentiate the two graphs, you can change the color of the

graph by clicking on the Plot Color/Style in the Dataset Table area below the graph:

Step 3: Choose two contrasting colors for your graph, like the graph shown below:

Step 4: Next you will hide one graph, so that you can examine the number of peaks on

the other. This will allow you to count how many yes votes, and how many no votesthere were. To hide a graph, click on the eye icon,as shown below:

Step 5: Count the peaks on the graph for touch sensor 1:


12/34



1 2 3 4 5 6 7 8 9 10

Touch sensor 1 votes: 10

Step 6: Hide the graph for touch sensor 1 and show the graph for touch sensor 3. Count

the number of peaks on the touch sensor 3 graph.


13/34



1 2 3 4 5 6 7

Touch sensor 3 votes: 7

Step 7: You can also analyze your data by examining your Dataset Table. A value of 1.0indicates the sensor is pressed and a value of 0.0 indicates that the touch sensor is not

being depressed.

Reflection:

This activity shows how data collection can be automated and used to collect data frommultiple sensors while you are not actually by your NXT, producing visible results.

Think of other experiments that could be set up in a similar way.


14/34

Test Your Knowledge Book DI: NXT Data LoggingLevel 1


Explore What You Have Learned

Challenge: Below are some suggestions of ways that you can use what you have learned

about data logging to do further exploration. Can you think of any other ways to test yourknowledge?

What is the lowest and highest light level readings you can get when you sit atyour computer?

What light level readings do you get when you cover the light sensor with yourhand?

Think of other questions to vote on using your touch sensors.

What values to do get when you check the reflected light option and point thelight sensor at different materials?

TestYourKnowledge


15/34

Measuring Wheel Book DI: NXT Data LoggingLevel 2



Measuring Wheel

Lesson Objectives:

In this lesson you will use your NXT vehicle to figure out how many rotations yourwheels make over a certain distance.

Challenge:

In this challenge, you will configure an experiment inNXT Data Loggingto performremote data collection of rotation sensor data. You will download this experiment to your

NXT brick and disconnect it from the computer. You will then physically push yourvehicle along the ground over a specified distance to perform the experiment. You will

upload this rotation sensor data to decipher how many rotations your wheels make as thecar is rolled a specific distance. You can use this data to figure out how many rotations it

will take your car to drive a mystery distance.

Building Procedure:

Step 1: Build an NXT two-motor vehicle.

Step 2: Wire one motor to output port B and the other to output port C.


Step 1: Open up NXT MINDSTORMS v. 2.0. Click on in the upper left.

Step 2: You will be directed to the StartData Loggingmenu. Type the name of yourexperiment in the Start New Experimentbox.


16/34



Step 3: Click the button to the right of the orange Start New Experimenttitle

box to continue.Step 4: The Experiment Configuration Panel will appear. Configure your experiment to

collect rotation sensor data from output port B for 10 seconds at a rate of 5 samples asecond. Shown below:

Step 5: Click ok to open your new experiment.

Data Collection:

Step 1: Unlike the previous two data logging activities, you will download your programto your NXT and disconnect the vehicle from the computer to collect data. To do this,

connect your NXT vehicle to your computer via the USB cable. Click the downloadbutton (shown below) to transfer your experiment from the computer to the NXT brick.

Step 2: Disconnect your NXT vehicle from the USB cable. Bring the vehicle to a tape

measure or ruler on the floor.

Step 3: Run the experiment on your NXT. Navigate to the software file of your

experiment by selecting the orange button. Select the file and click Run to start yourexperiment. Once your program is running, physically roll your NXT vehicle along the

ground for a measurable distance (e.g.1 meter, 5 feet, 16 inches).

Step 4: Return to your computer and reconnect the USB cable to the NXT brick. Click onthe upload button to transfer the data from your NXT brick to the computer.


17/34



Step 5: The following box will appear and will list all the experiments that are stored onyour NXT:

Note: All logs that are stored on your NXT will be displayed here. The most recent logwill be at the very top of the logs that are listed. You can delete logs to make space on

your NXT by clicking on a log and then clicking the delete button in the lower leftcorner.

Step 6: Click on the experiment(s) you would like to upload, they should be highlighted

(shown below):


18/34



Step 7: In the lower right-hand corner of the screen you should select open log in theAfter Upload dialog box. This will open the data set selected in a new window. If you

select import log, you can open multiple data sets in the same window. For thisexperiment you will only need to open one data set.

Step 8: Click ok to open your graph and begin analysis.

Data Analysis:

Step 1: The graph of your rotation sensor data should appear in the graphing space andlook similar to the graph shown below:

Step 2: To change the y-axis of your graph so that you have a better view of your graph

click on in the lower left-hand corner.

Step 3 (Point Analysis): You can find the total number of rotations using two different

analysis tools, point analysis and section analysis. First select the point analysis tool fromthe tool bar at the top of the graphing window:


19/34



Step 4 (Point Analysis): When you select this tool, the computer will automaticallyplace the point analysis bar onto your graph. You should move this point to the highest

point on your graph by clicking on the yellow line and holding down your mouse to movethe line.

Step 5 (Section Analysis): Use the section analysis tool to accomplish the same task.When you select the section analysis tool it will automatically place a grey bar on your

graph:

Step 6: Move the grey bar to cover the entire graph. The maximum value will be the total

number of rotations that the wheel on your NXT vehicle made over the distance youpushed it.

Optional Challenge:

Step 1: The instructor will give a mystery distance for your vehicle to travel.

Step 2: Click to open up a new program where you will tell your car to drive

(separate from your experiment). Call your new program drive:


20/34



Step 3: click Go to open up the programming window. Place a move block into your

drive program:

Step 4: Using the information collected in your graph, figure out how many rotationsyour wheels must make to travel the distance specified by the instructor. Use the

proportion you came up with in your experiment (e.g. 2 rotations for 6 inches or 2 rot/6in) Cross multiply to figure out the number of rotations you will need to travel the

distance specified by the teacher

# of rotations from experiment = ? RotationsDistance from experiment mystery distance

Example:

2.75 Rotations = ? Rotations1 Foot 3 Feet

= 2.75 x 3 = 8.25 Rotations

Step 5: In the configuration panel of the move block, enter this number of rotations youcalculated:

Step 6: Connect your vehicle to the computer via the USB cable. Download yourprogram by clicking on the download button in the lower right corner of the

programming workspace.

Step 7: Disconnect your vehicle from the USB cable, and run your program by selectingit with the orange button the NXT brick. Measure how far your car travels when you run

the program. Did it travel the distance the instructor specified?

Conclusion:

This activity can be connected to the Going the Distance programming activity in

which you program your car to travel for several different times, measure the distanceyour vehicle travels, and create a distance-time graph. The graph is then used to predict

how long you must program your vehicle to drive to stop after a mystery distance. Thinkabout the pros and cons of using time or rotation measurements to program your vehicle

to travel a given distance.


21/34




Into the Dark

Lesson Objectives:

To understand how to collect data from a moving NXT vehicle. This lesson requires theuse of both NXT Data Logging and programming.

Challenge:

In this challenge, you will combineNXT Data Loggingand Programming to accomplish atask. You will write an experiment to collect light sensor data. You will incorporate this

experiment into a program so that you can collect data as your car drives. You will thenupload the data to analyze how the environment around the car changes as it drives.

Building Procedure:

Step 1: Construct a two-motor NXT vehicle. Attach a light sensor to the front of the car.Orient the light sensor so that it is pointed horizontally.

Step 2: Wire one motor to output port B and the other to output port C.

Step 3: Wire the light sensor to input port 2.


Step 1: Open NXT MINDSTORMS v. 2.0. Click in the upper left corner ofthe window to openNXT data logging.

Step 2: Type the name of your experiment in the Start New Experimentbox.


22/34



Step 3: Click the button in the Start New Experimenttitle box to continue.

Step 4: The Experiment Configuration Panel will appear. Configure your experiment tocollect light sensor data from input port 2, for 10 seconds, at a rate of 5 samples a second.

You should collect ambient light conditions. Therefore, uncheck the reflected lightoption. Shown below:

Step 5: Click ok at the bottom of the Experiment Configuration panel to open the

graphing workspace.

Step 6: You will now use the experiment that you configured in step 4 in a program thatwill collect this information as the NXT vehicle performs other actions. In the Tools

menu option on the top bar of your computer, select Create Data Logging Program

Step 7: The NXT programming window will appear with a programming block already

in the workspace. This programming block is a Start Datalog block, which signals your

NXT to record information from the environment depending on how your experiment isconfigured.

Step 8: Add a Move Block to the program so that your car will drive as it collects data.Place this block before the Start Datalog Block. The Move Block is found in the common

menu.

Step 9: Configure the Move Block as shown below. The block should signal the car todrive straight for an unlimited amount of time. Because the NXT brick reads programs


23/34



from left to right, it will read the Move Block, tell the motors to turn, and then read theStart Datalog block to begin the experiment as the car is driving.

Step 10: Configure the Start Datalog block like the one shown below. You should be surethat the wait for completion option is checked. This ensures that the program will not

move to the next block until the data logging has taken place.

Step 11: Add a Move Block after the Start Datalog block to stop the car after theexperiment is complete:

Step 12: Configure this Move Block as shown below:

Step 13: Click on File in the top tool bar and save your file as lightdrive.

Step 14: Connect your NXT vehicle to the computer via the USB cable. Download the

program to your NXT vehicle by clicking the download button in the lower right corner.


24/34



Data Collection:

Step 1: Disconnect your NXT vehicle from your computer and bring it to an area of the

room with enough space for your car to drive forward for 10 seconds, but so that it will

drive into a darker area, like under a desk, or away from a light source.

Step 2: Select the lightdrive program from the software files, and select Run using the

orange button to begin your program. Your car should drive forward for 10 seconds,collecting light sensor data as it drives.

Step 3: Make multiple runs (2 3) of different areas in the room, you will compare these

samples as graphs in NXT data logging.

Data Analysis:

Step 1: Return to your computer and reconnect your NXT vehicle to the USB cable.Return toNXT data loggingby clicking on the icon in the upper left corner:

Step 2: Click on the upload button in the lower right corner of your graphing space:

Step 3: Your log files will appear. If you only want to open one of your logs, highlight

the log file by clicking on it. At the bottom right of the screen, select open log and clickon upload

Step 4: To upload multiple log files, select the log files, check the option import log,and click the upload button:


25/34



Step 5: You will be directed to the graphing workspace inNXT data logging. The graphs

of the log files that you just imported should appear. Change the color of these graphs sothat you can easily identify them by clicking on the change color/plot icon.

Step 6: Zoom into the graphs by clicking in the lower left corner of your graph,

below the y-axis. Your resulting graph should look similar to the graph below:

Step 7: You can use the analysis tools to examine differences between your two graphs.Click on the section analysis tool from the toolbar about your graphing space:

Step 8: Drag the section analysis tool to cover the entire 10 seconds of your logs by

clicking on either side of the bar and dragging it to the edge of the graph. You can viewthe minimum and maximum values for each graph and compare these values:


26/34



Step 9: Select the Show Linear Fit option at the bottom of the section analysis box.This will place two linear fit lines on your graph and give you the equation for these

lines. Compare the slope of these graphs. Which situation did the light levels change thefastest? Which situation did it change the slowest?


27/34

Test Your Knowledge Book DI: NXT Data LoggingLevel 2


Explore What You Have Learned

Challenge: Below are some suggestions of ways that you can use what you have learned

about data logging to do further exploration. Can you think of any other ways to test yourknowledge?

Can you program the car to turn while it collects light sensor data rather thandriving in a straight line?

Program your car to drive while it collects light sensor data. And then drive backto you so that you do not have to go retrieve it.

Program your car to collect rotation sensor data as it drives. How many rotationsper second is your car driving? What if you change the power level? Run multipletrials to test different power levels.

Test

YourKnowledge


28/34

Hidden Letter Book I: NXT-G Data LoggingLevel 2

DI - 27Copyright 2009 Tufts University Center for Engineering Education and Outreach


Hidden Letter

Learning Objective:

To understand how to collect data from a moving NXT vehicle, and how to interpret thisdata usingNXT Data Logging.

Student Challenge:

In this challenge, you will program your NXT vehicle to collect light sensor data while itis driving. The vehicle will drive over a letter of the alphabet that is hidden from view in

different positions to collect light sensor data. You will use this data to decipher whichletter of the alphabet your NXT has driven over.

Building Procedure:

Step 1: Build a NXT two-motor car with a light sensor mounted vertically so that it canmeasure reflected light levels off of the floor.

Step 2: Wire one motor to output port B and the other motor to output port C.

Step 3: Wire the light sensor to input port 1.


Step 1: Open NXT MINDSTORMS v. 2.0. Click t o access theDataLoggingmenu.

Step 2: In theData Loggingmenu, type the name of your experiment Hidden Letter -into the orange Start New Experimenttitle box.


29/34



Step 3: Click the button to the right of the Start New Experimenttitle box.

Step 4: The experiment configuration panel will appear. Configure your experiment like

shown below. Collect reflective light sensor data for a period of 10 seconds at a rate of 5samples per second.

Step 5: You should be sure that the reflected light option is checked. Since you arecollecting information from a piece of paper that may be hidden in a dark space, it is

important that your light sensor is generating light. The NXT will measure the amount of

light that is reflected back from the light that it is generating. This will be useful indetecting the differences between the white and black areas on the paper.

Step 6: To collect data while your NXT vehicle is driving, you must convert theexperiment that you just configured (Hidden Letter) into a programming block.

Select the Create Data Logging Program under the Tools menu in the top toolbar.

Step 7: The NXT programming interface will appear with a programming block already

in the workspace. This programming block is a Start Datalog block, which is configuredto collect data depending on how you configured your experiment inNXT Data Logging.


30/34



Step 8: You will add two programming blocks to complete your program. Place oneMove block before the Start Datalog block and the other one after. The Move block is

located in the Common submenu on the left hand side of the programming workspace.

Step 9: Program the first block to drive for an unlimited amount of time at a low power.Since your NXT will read the program from left to right, the program will jump from the

first programming block immediately to the Start Datalog block. As the car is driving itwill perform the experiment as it is configured in the Start Datalog block. You should

check the wait for completion option in the Start Datalog block to ensure that the NXTdoes not jump to the last programming block before the experiment is complete. The last

programming block will signal the NXT vehicle to stop driving before the program ends.

Each block should be configured as shown below:

NOTE: In the Start Datalog block, the Wait for Completion option should be checked This will ensure that the car will continue to drive while the experiment is taking place.

Step 10: Save this program with the titleHidden Letter.


31/34



Step 11: Connect your NXT brick to your computer via the USB cable. Download yourprogram to the NXT brick using the Download Button. When the program download is

complete, disconnect your NXT from the USB cable.

Data Collection:

Step 1: Unplug your NXT vehicle from the USB cable and place it so that it will drive

over the letter of the alphabet that is hidden from view.

Step 2: Run theHidden Letterprogram by selecting Run using the orange button.

Step 3: Have your vehicle drive over the hidden letter several times at slightly differentlocations to collect multiple logs. (see diagram below)

Data Analysis

Step 1: Reconnect your NXT brick to the USB cable. Be certain the NXT is on.

Step 2: Return to theNXT data loggingby clicking the button at the top left

corner of the programming workspace.

Step 3: You will be directed to the graphing workspace inNXT Data Logging. Click theUpload Button in the Data Logging Controller in the lower right corner to transfer your

data from the NXT brick to the computer.


32/34



Step 4: The log files that are stored on your NXT will appear in the log upload window.The files are organized by the time that they occurred, with the most recent log at the top

of the list. For this activity, you will want to import multiple logs. Select multiple logs byclicking on a log and holding down the CTRL button to select others.

Step 5: After you have selected the files that you will upload, select the option ImportLog after upload. This option will open up all of your logs in the graphing workspace.

Click upload to open these files.

Note: Depending on the number of trials you perform, or the number of other program(s)

stored on your NXT, you may need to delete files to make space for more. You can dothis in several ways. You must have your NXT connected to perform these actions

Option 1 Upload Menu: After you select the upload icon you can not only

import logs, but also delete them. Highlight the logs that you would like to delete,and select delete at the bottom of the screen.


33/34



Option 2 NXT Data Window: Select the NXT Data button in the DataController at the lower right corner of the graphing workspace:

A window containing data specific to your NXT will appear. Select the Memorytab. Select Programs next to the bar on the left of the window, which shows the

memory allocation, to view programs that are stored on your NXT. Select anyprograms that you would like to delete, or delete all your programs by selecting

Delete All

Step 6: All of your graphs will open at once in the graphing workspace.

Step 7: Examine each graph one at a time using the hide/show button in the Dataset

Table space. Keep in mind the order that you performed your trials and the orientationthat the car was pointed. The most recent log should be at the top of the list:


34/34


Step 8: Each graph will look similar to the graph shown below. There will be areas ofdark and areas of light. Dark areas will be lower values than light areas. Use this

information to try to figure out the letter that your car was driving over.

Example: For the following scenario (the letter A), the graphs may look as follows:

Off the

paper, onthe floor

On the white part

of the paper

Driving over black

ink (letter)

A

A

3

2

1

1 2 3

A B C

A B

C

Documents

Tufts Datalogging Book 1