R&D use of NXT

We need a controllable “moving platform” for demo purposes in a model urban environment. Since I work with LabVIEW and NI products, the Mindstorms NXT line seems worth considering, but I have a few concerns.
1. Does this product fit into a professional environment, in terms of reliability, strong construction, and (not too much of a) toy-like appearance?
2. Is there a place to get more specs on the various attachments? Right now we need more information on fast the servos can rotate, load vs. speed curves, weight limits, etc.
General comments about and experiences with using this “toy” in a R&D lab would be greatly appreciated.
Jim

Hallo Jim,
I'm working on the NXT in a laboratory. I'm tring to make a different humen-robot interface and try out some different kinds of positioning systems. Very often my supervisor comes in the lab with gasts and shows al the project we are doing here. And also mine, and these gasts never laught at me.
with kind regard,
Andries

Similar Messages

How to use DAQ to control Mindstorms NXT in real time?

I have a project in which I must use a a biosignal to control a Lego robot in real time. My group is using a DAQ to read an EMG signal into the computer. We are trying to use the RMS of this signal to control the power of the Servo motors that drive the robot. However, the DAQ assistant can not be loaded into the NXT (the error message says something about password protection).
Is there any way to read the RMS from another vi and feed it into the vi that is loaded into the NXT?
In general terms, what I would like to do is use the root mean square of a biosignal read by a DAQ to control the power of the Servo motors, in real time.
Any help would be greatly appreciated.
Attachments:
Master File.vi ‏65 KB

You won't be able to run DAQmx VIs on the NXT. The error message is misleading -- the problem is that the DAQ VIs weren't written to run in the NXT's virtual machine.
Instead, you should create two separate VIs. The first VI will run completely on the PC, will acquire the EMG signal, and then pass messages to the NXT over Bluetooth indicating how much power the motors should get.
The second VI will run completely on the NXT, will read messages from one of the Bluetooth mailboxes, and then feed that power value into a motor control VI.
If Bluetooth is not an option for you, you could use just one VI running on the PC, and use the NXT direct command VIs to set motor power over USB. (The drawback is that your NXT is now tethered to the computer.)
James Blair
NI R&D

LEG0 - NXT : Questions from a newcomer

Hello,
Although the box has been standing on my desk for the last 6 months or so, this is the first time I'm giving a serious look at it.
I have connected all the stuf, run the demo application, downloaded the LabVIEW toolbox, verified that the examples were working. I even have a project ! Great !
Of course I could run like that for a while and I'm sure exploration would be fun.
However, I believe that I can also benefit from the experience you have all accumulated on the subject, and considereing this board, avoid reading through most of the exchanges - a serious volume, often obsolete by now.
Would you help me on my track ?
I have a few questions :
1/ What should I read first ?
2/ What should I do first ?
3/ Have you some experience of using LabVIEW on a Macintosh running Windows XP (with VMware or Parallel) ? Specifically about bluetooth connection ?
4/ What kind of accuracy/reproducibility can I expect from the servomotors ?
Thanks for your help !
I can confirm the recent forum update is buggy - This post was intended in the NXT board !
Message Edité par chilly charly le 11-05-2007 03:49 AM
Chilly Charly    (aka CC)
         E-List Master - Kudos glutton - Press the yellow button on the left...

Thanks Bob !
Handling the thing to a young boy is indeed a good idea. That would be a real fun ! Unfortunately I have no kid at hand : mine is already 29 years old. Sure he would enjoy the job, even if a bit too old, but he is too busy presently. And, since he has not founded a familly yet, I don't have a grandson as spare part.
My goals are multiples :
    2/ use Lego NXT as a teaching tool for my bioengineering students. I'm sure they will enjoy it !
   1/ Play for myself.    I would like to take sky night pictures, and to get still images of the stars during the long exposure time required, I wonder if I could build an equatorial mount to hold my DSLR camera and compensate the earth rotation.
Sorry for the multiple posts. Seems the tab bug is still active... Long time no see...
Chilly Charly    (aka CC)
         E-List Master - Kudos glutton - Press the yellow button on the left...

Works in Main Application mode but not the orange NXT mode for some NXT's

A simple Labview program designed using only NXT VI's worked in the Main Application but not in NXT mode. For some NXT's it worked in both modes but for others, just in Main Application mode. I've tried updating the firmware and plugging and unplugging the USB. Any thoughts?

I see. The problem is probably that when you are switching to the NXT Target mode, it is expecting to target the other brick to which you already deployed. If you right-click on the orange banner menu in the lower left corner, you should be able to select the other NXT, or use "Find NXT..." to scan/search for bricks.
Also, I reccommend giving all your NXTs unique names so this is more obvious. (you can use the NXT Terminal tool to do that).
If you still can't get the VI to run in target mode, restart labview.

LabVIEW NXT toolkit and Vista

Hi All,
This is not a burning problem, but have folks tried out the NXT toolkit with Vista? I've installed Vista Business Edition under our MSDNAA license on a development machine to start slogging through compatability issues with our current suite of software, and it appears the LabVIEW NXT toolkit may be an early casualty.
The toolkit installs fine under Vista BusEd, but the NXT console application crashes when I try to run it from the LabVIEW IDE menu.
Any thoughts/experiences with this?
Best regards,
-Bill =]

Hi Joel,
Thanks for your reply. The specifics of my development system are below:
OS: Windows Vista Business
Proc: Intel Pentium 4 CPU 2.80 GHZ
RAM: 1014 MB
Type: 32-bit OS
I chose to use the Vista UPGRADE of WinXPsp2 rather than a wipe and clean install. Before upgrading the OS I removed all previous versions of LabVIEW (7.1 and 8.0) and also removed the Mindstorms NXT-G system.
After the OS upgrade to 32-bit VistaBusEd, I installed LabVIEW 8.20, then Mindstorms NXT-G, several LabVIEW Toolkits and finally the LabVIEW NXT Toolkit.
When I try to load LabVIEW code that uses (for example) the sendDirectCommand.vi from the FantomSDK, I get the following block diagram error:
"Call Library Function Node 'fantom.dll:nFANTOM100_iNXT_sendDirectCommand': function not found in library
Details: The function name specified for this node cannot be found in the library. Right-click the Call Library Function node and select Configure, then choose the correct function name.
When I follow the Details procedure, I specify the exact location of the fantom.dll, select nFANTOM100_iNXT_sendDirectCommand from the Function name dropdown listbox, the Thread is set to Reentrant and the Calling convention is set to "C".........after closing the dialog I get:
Error loading "C:\.....path.....\fantom.dll".
A dynamic link library (DLL) initialization routine failed.
Also, when I create a blank vi and drop a function from the LabVIEW NXT toolkit, such as NXTToolkit.DC.FindNXT.vi on the block diagram, I imediately get the following similar error:
Error loading "fantom.dll".
A dynamic line library (DLL) initialization routine failed.
Does this help?
Many thanks,
-Bill =]
p.s. - BTW, the Minstorms NXT-G system works as expected under the 32-bit VistaBusEd using both USB and Bluetooth.....so I guess VistaBusEd is able to intialize and communicate through the fantom.dll when used by NXT-G.
Message Edited by qswitch on 12-19-2006 08:36 AM

LABVIEW NXT LEGO firmware problem

hi everybody
i am trying to connect LEGO NXT mindstorm robot with labview, i installed the latest version of LABVIEW toolkit. but when i tried to connect the NXT it gives me this error which i dont understand why, because i have latest version of toolkit installed in my PC with LABVIEW 8.6, and the upgraded firmware in NXT i.e 1.05 . even though i tried with 1.04 and 1.02 but it is still giving me the same error(attached). some one has idea whats wrong on my side?
thanks
looking forward
Regards
hussain..
Solved!
Go to Solution.
Attachments:
LEGO error.JPG ‏84 KB

The latest NXT toolkit release is 2.0, which has been posted recently. If you are using this version of the toolkit, the firware version should be 1.26. If you have installed NXT toolkit 2.0, you can update your firmware to 1.26 using Tools>>NXT Modules>>Update firmware.
To download 2.0, please follow the instructures on this page:
http://zone.ni.com/devzone/cda/tut/p/id/4435
Please let us know if this solves the problem.

NXT Flatten to String Not Working with Clusters and Arrays

Hello,
My name is Joshua and I am from the FIRST Tech Challenge Team 4318, Green Machine. We are trying to write a program that will write to a configuration file and read it back. The idea is that we will be able to write to a config file from our computer that will be read by our autonomous program when it runs. This will define what the autonomous program does.
The easiest way to do this seems to be flattening a data structure to a string, saving it to a file, and then reading back and unflattening it. The issue is that the flatten to string and unflatten from string VIs don't seem to work with arrays and clusters on the NXT. It does work when running on the computer. We've tried arrays, clusters, clusters in arrays and arrays in clusters, none seem to work. Thinking it was something to do with reading the string from a file, we tried bypassing the file functionality, still not working. It does work with basic data types though, such as strings and numbers.
No error is thrown from what we can tell. All you get is a blank data structure out of the unflatten VI.
The program attached is a test program I've been working on to get this functionality to work. It will display the hex content of what is going into the file, coming out of the file, and then the resulting data from the unflatten string, as well as any errors that have been thrown. The data type we are using simulates what we would like to store. There is also a file length in and out counter. The out file is a little larger because the NXT write file VI adds a new line character on to the end (thus the use of the strip white space VI). This character was corrupting even basic data types saved to file.
I would like to know if there is a problem with what we are doing, or if it is simply not possible to flatten arrays on the NXT. Please ask if you have any questions about the code. Thank you in advanced!
Joshua
Attachments:
ReadableTest.vi ‏20 KB

Hi jfireball,
This is a very interesting situation. Take a look at what kbbersch said. I also urge you to post in the FTC Forums. You posted your question to the general LabVIEW forums, but by posting to the FTC Forums, you will have access to others that are using the NXT hardware.
David B.
Applications Engineer
National Instruments

NXT Mindstorm Display Malfunction

I am running a class using the NXT Toolkit in LabVIEW. We used these same units last year in the same course. This year six of the Mindstorms work, but the display does not work. I've tried changing batteries to see if there is a voltage problem, but aside from that I do not have any ideas.
Suggestions?

You may be interested in the details of the discussion here:
http://forums.nxtasy.org/index.php?showtopic=2713
To summarize: if you're brave and have the right tools and knowledge, resoldering some capacitors will likely fix your problem. If not, calling the LEGO Education customer support line is also a good option.
[edit: added hyperlink to URL text]
Message Edited by James B. on 09-18-2008 04:45 PM
James Blair
NI R&D

Linux labview eval version for lego mindstorms nxt

Hi,
I'm a high school teacher in Tamil Nadu, India. Our school recently purchased 4 lego mindstorm NXT kits. We were happy to find that the new software was powered by labview, because it runs on linux. Our school runs on an Edubuntu LTSP network. So we were sad when we discovered the installation disk only supported MacOS and Windows.
I looked at the labview site for NXT and saw that we could get a student evaluation copy for use with NXT - so I filled out the forms, but when the link to the FTP site was given, it only provided a Windows and MacOS copy.
Can we obtain a student copy of labview for Linux for use with our NXT kits?
Thank you, Jason Stewart.

Hello Jason,
I'm sorry I didn't make this more clear in my previous post, but the LabVIEW Student Edition for use with LEGO® MINDSTORMS® NXT is only available for Windows. This will provide you with the LabVIEW 7.1 Student Edition and then you can download the LabVIEW Toolkit for LEGO® MINDSTORMS® NXT. This will give you the ability to create custom NXT blocks in LabVIEW.
Another option would be to purchase the latest LabVIEW Student Edition and then download the LabVIEW Toolkit for NXT. However, this edition is also only available for Windows. The customers that are downloading the LabVIEW Toolkit for LEGO® MINDSTORMS® NXT on a Mac OS have purchased the full version of LabVIEW for Mac.
Your best option would be to contact the NI India Sales Office at [email protected] or 91 80-4119 0000. They would be able to help you best with this.
Regards,
Clint M

NXT communication mailbox fails

Hi everyone,
I'm working with the Mindstorms 2.0 kit and using Labview 2009 SP1. I'm trying to get a message from my computer to the next using the mailbox VI. I've connected the NXT using USB. Now I'm trying the color sensor demo downloaded from here:
http://decibel.ni.com/content/docs/DOC-11109
Now I've uploaded NXT_Client using the NXT [USB] instance. It says its 'running'. Now I load the PC_Host, switch back to Main Application Instance, and run. Then PC_Host gives me the message below.
Now I'm not sure why it says this, since the NXT_client is running.
It does however seems to work somewhat!? It gives me the right color, it just displays this error in every iteration of the loop.
I tried starting the NXT Shell, however, that just displays <0> when I run the PC_Host, and if I run the NXT_Client after the NXT Shell it just replaces it...
I'm not sure how this should work, but I'm not getting it to work. Anyone has any ideas what I'm doing wrong?
Regards,
Vincent

I have futher looked into this problem.
To me, it seems there is a bug in the labview VI's. During the program it will run into 'BlueTooth_Write_String.vi'. (Even though I'm communicating through USB... however, this doesn't seem to be an error). Which in turn invokes SendCmdToDebug.vi.
Now, send SendCmdToDebug has 'Request Reply' boolean, which is True by default. As you can see in the diagram True means also then checks for whether or not the NXTShell is running, and give an error if it isn't! Now it is unwired in BT_Write_String, meaning it always checks whether or not NXTShell is running. But its not! my own program is trying to receive the command.
Did anyone else experience this problem? Is it not a bug? Please let me know.
Regards,
Vincent

Differences between LabVIEW Education Edition and LabVIEW 2009 + NXT Module

Recently saw the announcement regarding LabVIEW Education Edition.
From the information available at this time it's hard to tell the difference between this product and just adding the NXT module to standard LabVIEW 2009 if your only interest in LabVIEW is for NXT programming. Anymore details about this new product would be appreciated as well as info on how it's different from the alternative. Are there some unique VIs not present in the standard NXT module? Obviously the pricing is very different, but for a student the academic version of LabVIEW is actually lower cost than this new Education Edition.

Inh-
LabVIEW Education Edition (LVEE) includes the NXT Module and the API to interface with Vernier products. LVEE is geared towards middle school and high school classrooms to get students interested in math and science. It includes curriculum for teachers that may not be familiar with programming and LabVIEW in general to use the NXT bricks and the LabVIEW environment.
LabVIEW with the NXT module only has the NXT API and not the Vernier API. It will not include the course work and as extensive example programming useful for teaching.
For additional information on LVEE, please take a look at the Getting Started with LabVIEW Education Edition or go to ni.com and search for “labview education edition”.
Regards,
Mike S
NI AE

Teaching LabVIEW to engineering students: is the NXT Toolkit recommended?

We have used NXT kits in our freshmen engineering design course with great success. We may overhaul our curriculum to replace ROBOLAB with the LabVIEW NXT Toolkit (our second choice would be NXT-G). We would like to give our students an early exposure to LabVIEW. We are hesitant about the sparse documentation and programming sophistication needed to effectively use the Toolkit. However, we believe we can overcome these concerns by locating and/or developing appropriate teaching materials.
We would appreciate hearing comments and/or experiences regarding the suitability of the Toolkit for this purpose. We are especially interested in knowing if further documentation (beyond the three PDF’s on the NI website) is available or planned. If anyone else is teaching the Toolkit in engineering courses, we would be very interested in a mutual exchange of course materials.
Thank you in advance for any guidance!
Matthew G. Green (w/ Greg Reynolds)
School of Engineering & Engineering Technology, LeTourneau University, Longview, TX

Matthew,
I am currently in the process of getting some resources together that might prove very helpful for you. If you look at this site,
http://zone.ni.com/devzone/cda/epd/p/id/5221
you'll see some labs that were made in the NXT-G software for a high-profile university. They were used in a freshman entry-level engineering lab and they proved highly successful for all involved.
I'm working on getting them ported over to a LabVIEW version that uses the NXT toolkit, but by looking at the labs you'll see that this is a process that could probably be done on your end without much of a time investment.
I'll try to let you know when I'm done with the project and can share the labs with you!
-Pete
Peter L.
Applications Engineer
National Instruments
www.ni.com/support/

Nxt with touch sensor

Hi I'm looking for some help. I want the touch sensor when pressed to run a loop that causes 1 motor of the nxt to run moving a certain distance at a certain power and then stop. Then I want it to run again when the sensor is pressed (running the same loop) but only running on the press of the sensor when the sensors pressed. I have tried using a case structure and by putting the same circuit I the true and false case I thought it might work but it doesn't and it wasn't a very practical solution
Can you help??
Ailish

Hi Paul
Since I posted this I have changed my mind about what I am looking for the nxt to do. I will give you some background info an hopefully you can help.
Firstly I am using two NXT motors. The first one I have built an arm onto the motor, I want to move a set degree (egg 1degrees) at a set speed. As the NXT move further down( by 1 degrees ) it will apply pressure on a FSR. The FSR will be zero until the arm moves down(by 1degree) an applies the smallest pressure. But when the pressure on the FSR changes I want the DAQassist which is taking in the FSR signal to record the pressure applied at 1degree an output it to the user on the front panel showing the number. Then as the NXT moves down again the FSR resistance changes again and a new number is logged.. Is it possible to do this?? I will attach my code at present.
If I could get that working correctly it would be excellent
Secondly the other NXT motor has another arm built on it where I am placing an Accelerometer. I need this motor to move 180degrees at a speed of 20 forward and then move 180degrees at a speed of 60 (given a ratio of 3:1) backwards. carrying out this motion continuously. The accelerometer will also be attached to the DAQ and then I want the same DAQassist (because I tink you can only have one DAQassist per program) to out the accelerometers movement on a graph. Is this possible??
Thank you Ailish
Attachments:
xyzacc.vi ‏165 KB

Integration with the Lego NXT

I have a Gyroscope which I have connected up to the NXT and I am now trying to find the angle that it is operating at from the starting position. I was wondering if anybody knows howto carry out integration using the NXT toolkit. Or even if there is an icon of one of the sensor blocks which alows me to see the angle from starting possition.

Hi skinheadi...,
there should be a vi to read the sensor position. Search in the input section.
Mike

NXT custom output

I'm constructing a robot for a school project in which I am needing to use custom NXT inputs and outputs. For my input I am needing the NXT to recognize a voltage sent to it from a metal detector (between 1.5 and 1.9 volts) and then rotate a motor, to specific degrees that correspond to a sorting device I have made. Secondly I need a custom output that will send a voltage to a solednoid to life a plunger to allow a coin to fall through a hole. I am having troubles creating code that will succesfully run, and perform the actions desired....any help will be much appreciated.
Solved!
Go to Solution.

Hi LracNayr,
I'm not familiar with the NXT. What I can offer is going to be more of a top
level approach to trouble shooting. I would recommend that you visit the Lego
FAQ webpage for more specific trouble shooting steps.
If you are having an issue with reading in the input, the first step I would
take is to read the raw voltage output from the metal detector using a DMM.
Your metal detector may not be outputting the correct voltage for each of the
corresponding coins. Once you have verified that the output voltage is correct,
I would go on to test the raw voltage reading with the NXT hardware. With NI
products, you can accomplish this using Measurement and Automation (MAX). I do
not know if this is possible with NXT, however, the general principle will be
the same. You want to verify the output voltage from the hardware first before trouble
shooting the software. When that's done, it's unlikely that you will see an
error assuming that you are using the appropriate functions.
I hope this helps. As stated before, NI does not support this particular
product. I strongly recommend that you visit the link I send you with a
previous post.
Regards,
Josh L.
Applications Engineer
National Instruments

R&D use of NXT

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